U.S. patent number 3,840,752 [Application Number 05/360,834] was granted by the patent office on 1974-10-08 for electronically programable switching system.
This patent grant is currently assigned to U.S. Philips Corporation. Invention is credited to Kamran Eshraghian.
United States Patent |
3,840,752 |
Eshraghian |
October 8, 1974 |
ELECTRONICALLY PROGRAMABLE SWITCHING SYSTEM
Abstract
A switching device comprises a plurality of control points and a
plurality of switching elements, and each control point is
associated with one or more switching elements. The switching
elements are actuated by the presence of actuation information at
the associated control point. A shift register having states
related to the control points supplies actuation information to the
control points in a predetermined sequence under the control of
timing pulses which advance the states of the register whereby a
series of combination of switching functions may be performed.
Inventors: |
Eshraghian; Kamran (Hillcrest,
AU) |
Assignee: |
U.S. Philips Corporation (New
York, NY)
|
Family
ID: |
3737788 |
Appl.
No.: |
05/360,834 |
Filed: |
May 16, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Jan 23, 1973 [AU] |
|
|
51379/73 |
|
Current U.S.
Class: |
307/141;
340/4.3 |
Current CPC
Class: |
D06F
34/06 (20200201); D06F 33/00 (20130101); G05B
19/07 (20130101); D06F 34/08 (20200201); G05B
2219/25267 (20130101) |
Current International
Class: |
D06F
33/02 (20060101); G05B 19/04 (20060101); G05B
19/07 (20060101); H01h 043/00 (); B01f
003/00 () |
Field of
Search: |
;307/141,115 ;340/147P
;134/57R,57D,58R,58D ;317/137,140 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schaefer; Robert K.
Assistant Examiner: Smith; William J.
Attorney, Agent or Firm: Trifari; Frank R.
Claims
What is claimed is:
1. A switching device comprising: a plurality of control points and
a plurality of switching elements, each said control point being
associated with one or more of said switching elements, said
switching elements being actuated by the presence of actuation
information at said associated control point, a shift register
having states related to said control points for supplying
actuation information to said plurality of control points in a
predetermined sequence under the control of timing pulses which
advance the states of the register whereby a series of combinations
of switching functions may be performed, the intervals between
occurrence of consecutive timing pulses determining the period of
time for which actuation information is present at the respective
control points, a pulse supply means capable of supplying to the
shift register timing pulses either recurring at relatively long
intervals or recurring at relatively short intervals, means for
deriving programme information from the actuation information
present at said control points, the derived programme information
being applied to said pulse supply means for determining, in
accordance with a programme, whether the timing pulses supplied to
said shift register recur at relatively long intervals or recur at
relatively short intervals, a multistable programme override
circuit having two stable output states, one output state providing
for continuous supply to the shift register of timing pulses
recurring at relatively short intervals, the other output state
providing for supply to the shift register of timing pulses
recurring at either relatively long intervals or at relatively
short intervals in accordance with the programme, transition of the
output state of the override circuit being controlled by
information derived from one or more control points.
2. A switching device as claimed in claim 1, wherein said pulse
supply means includes a discrete first pulse source for producing
pulses recurring at relatively long intervals, a discrete second
pulse source for producing pulses recurring at relatively short
intervals and further including a selection circuit selectively
making said shift register responsive either to said first pulse
source or said second pulse source, said selection circuit being
responsive to said override circuit output information and when the
output of said override circuit is in said one output state said
selection circuit permits timing pulses to be derived only from the
said second pulse source and when the output of said override
circuit is in the said other state, said selection circuit permits
timing pulses to be derived from either the first or second pulse
source in accordance with said programme information.
3. A switching device as claimed in claim 1, wherein said pulse
supply means includes a pulse source from whence timing pulses may
be derived for supply to the shift register, the pulse source being
adapted to operate in either a first mode of operation or a second
mode of operation, the pulse source producing pulses recurring at
relatively long intervals when operating in the first mode and
producing pulses recurring at relatively short intervals when
operating in the second mode, said override circuit output
information being so applied to control the pulse source that when
the output of said override circuit is in said one output state
said pulse source operates only in the second mode, whereas when
the output of the said override circuit is in the said other state,
the pulse source operates in either the first or second mode in
accordance with the said programme information.
4. A switching device as claimed in claim 3, wherein in that the
said pulse source is in the form of a relaxation oscillator, the
repetition frequency of which is determined by the series
combination of two capacitors one of which is shunted by the
collector-emitter path of a transistor adapted to be rendered
either conductive so that the pulse source operates in the said
first mode or non-conductive so that the pulse source operates in
the said second mode, and further includes pulse source control
means for rendering the transistor conductive when the output of
said override circuit is in said one output state or conductive in
response to the said programme information when the output of said
override circuit is in the said other output state.
5. A switching device as claimed in claim 4 further including
switching means for switching said override circuit into or out of
a non-override condition in which the output of the override
circuit is in the said other output state and transition of the
output state is inhibited.
6. A switching device as claimed in claim 5 wherein a programme
selection means for providing selection information and comparison
means for comparing selection information thus provided with
actuation information present at the said respective control points
of the plurality produces said programme information.
7. A switching device as claimed in claim 6 wherein said programme
override circuit is a triggerable bistable device to which the said
actuation information produced at said predetermined control points
is supplied to trigger the bistable device into an opposite state
and thereby change the output state of the bistable device.
8. A switching device as claimed in claim 6 having said shift
register arranged to be arrested at the completion of a cycle of
the register states and in which the said programme override
circuit is a triggerable multistable device having more than two
stable states, one stable state producing information at an
auxiliary output of the multistable device which prevents the said
shift register from being arrested at the completion of a cycle of
the register states, the said actuation information produced at the
said predetermined control points being supplied to trigger the
multistable device.
9. An electronically programable switching system comprising:
a plurality of control points;
a plurality of switching elements, each said switching element
being operatively responsive to actuation information on at least
one predetermined control point;
A shift register supplying actuation information to said plurality
of control points in a predetermined sequence in response to timing
pulses which advance the states of said register, said shift
register being responsive to the intervals between the occurrence
of consecutive timing pulses to vary the period of time for which
actuation information is present at said plurality of control
points;
pulse supply means for supplying to the shift register timing
pulses at relatively short intervals and also at relatively long
intervals;
means for varying the interval between occurrence of consecutive
timing pulses responsive to the state of said control points.
Description
The present invention relates to switching devices of the kind
comprising a plurality of control points, each control point of the
plurality being associated with a combination of one or more
switching elements whereby the switching elements for each
combination are adapted to be actuated by the presence of actuation
information at the control point associated therewith, a shift
register having states related to the control points of the
plurality for supplying actuation information to the control points
of the plurality in a predetermined sequence under the control of
timing pulses which advance the states of the register whereby a
series of combinations of switching functions may be performed, the
intervals between occurrence of consecutive timing pulses
determining the period of time for which actuation information is
present at the respective control points, pulse supply means
capable of supplying to the shift register timing pulses either
recurring at relatively long intervals or recurring at relatively
short intervals, means for deriving programme information from the
actuation information present at respective control points, the
derived programme information being applied to the pulse supply
means for determining, in accordance with a programme, whether the
timing pulses supplied to the shift register recur at relatively
long intervals or recur at relatively short intervals.
Such switching devices are proposed in the applicant's co-pending
Australian Pat. application Nos. 48775/72 and 49305/72.
In one known kind of switching device, the said pulse supply means
include a first pulse source for producing pulses recurring at
relatively long intervals, a second pulse source for producing
pulses recurring at relatively short intervals and a selection
circuit arrangement permitting timing pulses for supply to the said
shift register to be derived from either the first pulse source or
the second pulse source.
In an alternative known kind of switching device, the said pulse
supply means includes a pulse source from whence timing pulses may
be derived for supply to the shift register, the pulse source being
adapted to operate in either a first mode of operation or a second
mode of operation, the pulse source producing pulses recurring at
relatively long intervals when operating in the first mode and
producing pulses recurring at relatively short intervals when
operating in the second mode. With this kind of switching device
the said pulse source may be in the form of a relaxation
oscillator, the repetition frequency of which is determined by the
series combination of two capacitors one of which is shunted by the
collector-emitter path of a transistor adapted to be rendered
either conductive so that the pulse source operates in the said
first mode or non-conductive so that the pulse source operates in
the said second mode.
A switching device of the kind to which the invention relates
generally also comprises programme selection means for providing
selection information and comparison means for comparing selection
information thus provided with actuation information present at
respective control points of the plurality for determining, during
the course of the selected programme, whether the timing pulses
supplied to the shift register recur at relatively long intervals
or recur at relatively short intervals. Switching devices
comprising programme selection means are described in the
aforementioned Australian Pat. application No. 48775/72.
In a switching device of the kind to which the invention relates
and comprising such selection means, if desired, the said programme
selection means may be adapted to alter one or more of said
combinations of one or more switching elements upon alteration of
programme selection. In addition, or as an alternative thereto, a
manually operable switching element combination alteration means
may be incorporated in the device whereby alteration to one or more
of said combinations of one or more switching elements may be
accomplished independently of the programme selection means.
The programme selection means of a device of the kind to which the
invention relates may be relatively simple or may be complex
depending upon the application for which the switching device is
intended. It will be appreciated that the recurrence period of the
timing pulses recurring at relatively short intervals is chosen to
be only a few milliseconds for most applications and since each
timing pulse produced advances the state of the shift register, the
provision of selection information by the programme selection means
such that during the course of a selected programme a timing pulse
occurs at a relatively short interval after a preceding timing
pulse results in a corresponding state of the shift register being
occupied for a few milliseconds only also or, in other words, the
shift register is rapidly advanced. Under such conditions,
actuation information supplied to the appropriate control points
and the resultant actuation of switching elements related to the
state of the shift register in question is of such short duration
that for many applications of the device it may, for practical
purposes be regarded as an omission of one of the combinations of
switching functions from the series since the duration of the
combination concerned is compressed. For other applications, means
may be provided for inhibiting the actuation of the switching
elements for the total duration of a succession of timing pulses
recurring at relatively short intervals whereby one or more
combinations of switching functions may be omitted from the series
by the supply to the shift register of timing pulses recurring at
relatively short intervals.
As an alternative to providing such means for inhibiting the
actuation of the switching elements for the total duration of a
succession of timing pulses recurring at relatively short
intervals, suppression means may be provided, the suppression means
being responsive to the said programme selection information and/or
to information representing the existence of a physical condition
and/or to the actuation information present at the said control
point and being arranged to either prevent actuation of one or more
of the switching elements of a combination of a series related to
the programme in question or to permit such actuation and
counteract the effect of such actuation.
It is advantageous in some applications for the said programme
selection means to comprise a plurality of programme selection
switching members each associated with a particular programme, each
member being adapted to occupy either a selected state or a
non-selected state and each so related to the other members that
only one of the plurality may occupy the selected state at a given
time, the plurality of switching members collectively providing the
said selection information and, when all members of the plurality
occupy the non-selected state, the selection information so
provided in combination with the said actuation information
supplied to the control points determining the performance of a
basic series of combinations of said switching functions, whereas
when one of the members of the plurality occupies the selected
state the selection information so provided in combination with the
said actuation information supplied to the control points
determines the performance of the basic series of combinations of
said switching functions modified by the omission of one or more of
the combinations from the basic series and/or by the compression of
the duration of one or more of the combinations of the basic series
and/or by the substitution of one or more of the combinations in
the basic series by a different combination. However, for other
applications of the invention it is advantageous for the said
programme selection means to comprise a plurality of switching
members each associated with a portion of a basic series of
combinations of switching functions, each adapted to occupy either
a selected state or a non-selected state, the plurality of
switching members collectively providing the said selection
information and, when all members of the plurality occupy the
selected state, the selection information so provided in
combination with the said actuation information supplied to the
control points determining the performance of a basic series of
switching functions whereas when one of the members of the
plurality occupies the non-selected state the said selection
information so provided in combination with the said actuation
information supplied to the control points determines the
performance of the basic series of combinations of switching
functions modified by the omission from the basic series of that
portion associated with the member occupying the non-selected state
or by the compression of the duration of that portion of the basic
series associated with the member occupying the non-selected
state.
In a switching device where means for inhibiting the actuation of
the switching elements is provided, preferably the said timing
pulses recurring at relatively short intervals are caused to recur
periodically and for every timing pulse supplied to the shift
register, the actuation of the switching elements is inhibited for
a period of time commencing at or prior to the commencement of the
timing pulse and terminating at or after elapsement of a period
equal to the recurrence period of the timing pulses recurring at
relatively short intervals, Still preferably, every timing pulse
applied to the shift register is derived from a reference pulse
generator producing reference pulses of fixed duration, the leading
edges of the reference pulses being employed to determine the
commencement of the period of inhibition of the actuation of the
switching element and the trailing edges of the reference pulses
being employed to determine the instant of triggering the shift
register. With such an arrangement, the reference pulse generator
may be arranged to be triggered either from a source of trigger
pulses recurring at relatively long intervals or from a source of
periodically recurring trigger pulses recurring at relatively short
intervals.
The present invention provides a useful improvement to switching
devices of the kind to which the invention relates.
In accordance with the invention, a multi-stable override circuit
is associated with the said pulse supply means, the multi-stable
programme override circuit having two stable output states, one
output state providing for continuous supply to the shift register
of timing pulses recurring at relatively short intervals, the other
output state providing for supply to the shift register of timing
pulses recurring at either relatively long intervals or at
relatively short intervals in accordance with the programme,
transition of the output state of the override circuit being
controlled by information derived from one or more predetermined
control points of the plurality.
Different forms of the invention are possible. In one form of the
invention, the switching device is such that the said pulse supply
means include a first pulse source for producing pulses recurring
at relatively long intervals, a second pulse source for producing
pulses recurring at relatively short intervals and a selection
circuit arrangement permitting timing pulses for supply to the said
shift register to be derived from either the first pulse source or
the second pulse source, output information from the said override
circuit being so applied to the selection circuit arrangement that
when the output of the said override circuit is in the said one
output state the selection circuit arrangement permits timing
pulses to be derived only from the said second pulse source,
whereas when the output of the said override circuit is in the said
other state, the selection circuit arrangement permits timing
pulses to be derived from either the first or second pulse source
in accordance with the said programme information.
In another form of the invention, the switching device is such that
the said pulse supply means includes a pulse source from whence
timing pulses may be derived for supply to the shift register, the
pulse source being adapted to operate in either a first mode of
operation or a second mode of operation, the pulse source producing
pulses recurring at relatively long intervals when operating in the
first mode and producing pulses recurring at relatively short
intervals when operating in the second mode, output information
from the said override circuit being so applied to control the
pulse source that when the output of the said override circuits is
in the said one output state the pulse source operates only in the
second mode, whereas when the output of the said override circuit
is in the said other state, the pulse source operates in either the
first or second mode in accordance with the said programme
information. In this form, the said pulse source may be in the form
of a relaxation oscillator, the repetition frequency of which is
determined by the series combination of two capacitors one of which
is shunted by the collector-emitter path of a transistor adapted to
be rendered either conductive so that the pulse source operates in
the said first mode or non-conductive so that the pulse source
operates in the said second mode, pulse source contol means being
provided for rendering the transistor conductive when the output of
the said override circuit is in the said one output state or
conductive in response to the said programme information when the
output of the said override circuit is in the said other output
state.
Preferably, a switching device in accordance with the invention is
provided with switching means for switching the said override
circuit into or out of a non-override condition in which the output
of the override circuit is in the said other output state and
transition of the output state is inhibited.
When provided with such switching means, with the override circuit
in the non-override condition, the programme of switching
operations determined by the said programme information is
followed. However, with the override circuit not in the
non-override condition, with transition of the output state
controlled by information derived from predetermined control points
of the plurality, rapid advancement of the shift register through
one or more selected portions of the programme may be achieved. For
this purpose, the override circuit may be in the form of a
relatively simple bistable circuit.
The invention also offers the possibility, when the switching
device is provided with such switching means and with the override
circuit further modified in a manner to be described latter that
with the override circuit not in the non-override condition, with
transition of the output state controlled by information derived
from predetermined control points of the plurality, of the
switching device performing a series of combinations of switching
functions in accordance with a first portion of the programme,
whereupon the shift register is rapidly advanced, whole or part of
the performed programme is repeated and the remaining portion of
the programme is then performed.
If desired, the switching operations of the device may be inhibited
in known manner during such rapid advancement, for example in
accordance with the invention described in Australian Pat.
application No. 48775/72.
Preferably also, a switching device in accordance with the
invention includes programme selection means for providing
selection information and comparison means for comparing selection
information thus provided with actuation information present at the
said respective control points of the plurality to thereby produce
the said programme information.
This invention will now be described with reference to the
accompanying drawings in which:
FIG. 1 is a schematic diagram of a known switching device of the
kind to which the invention relates.
FIG. 2 illustrates wave forms to assist in describing the operation
of a part of the circuit illustrated in FIG. 1.
FIG. 3 illustrates wave forms produced at various parts of the
circuit of FIG. 1 in the course of operation of a particular
programme.
FIG. 4 is a schematic diagram of a switching device embodying the
present invention.
FIG. 5 is a schematic diagram of the multistable programme override
circuit of another switching device embodying the present
invention.
FIG. 6 is a schematic diagram of another known switching device of
the kind to which the invention relates.
FIG. 7 is a chart to assist in describing the operation of FIG.
6.
FIG. 8 is another chart to assist in describing the operation of
the circuit of FIG. 6.
FIG. 9 is a schematic diagram of a further embodiment of the
invention.
FIGS. 1, 2 and 3 of the accompanying drawings are identical with
FIGS. 1, 2 and 3 respectively of the complete specification of the
applicant's co-pending Australian Patent Application No. 48775/72
and FIGS. 6, 7 and 8 of the accompanying drawings are identical
with FIGS. 4, 5 and 6 respectively of that complete
specification.
In FIG. 1, the control points 1, 2, 3, 4, 5, 6, 7 and 8 are each
connected to the output of a stage of the shift register 9 having
stages 9a, 9b, 9c etc., control point 1 being connected to the
output of stage 9a, control point 2 being connected to the output
stage 9b etc. The shift register 9 is driven by timing pulses
supplied via the terminal 10. The shift register 9 is of known kind
and operates in a known manner. In an initial state, the control
point 1 is in the "high" state with the remaining control points
all at the "low" state. The terms "high" and "low" indicate, in the
present instance, a predetermined positive voltage level and a zero
voltage level respectively.
At the occurrence of the first timing pulse supplied via the
terminal 10, the shift register 9 is advanced so that the control
point 2 goes to the "high" state, the control point 1 goes to the
"low" state and terminals 3 to 8 remain in the "low" state. This
condition remains until the occurrence of the next timing pulse
whereupon the control point 3 goes to the "high" state and control
point 2 returns to the "low" state, control point 1 and control
points 4 to 8 remain in the "low" state. The process is continued
with the "high" state being transferred sequentially along the
plurality of control points 1 to 8 at the occurrence of successive
timing pulses. When the control point 8 is at the "high" state, the
next succeeding timing pulse results in the shift register 9 being
returned to its initial state.
The control points 1 to 8 are connected via the matrix 11 to the
switching elements 12, 13, 14 and 15. The switching elements 12,
13, 14 and 15 are each in the form of a transistor provided with a
load in its collector circuit. The load may be in the form of a
relay, a lamp, a resistance etc. The connections from the control
points 2 to 8 to the switching elements 12, 13, 14 and 15 are such
that each of the control points 2 to 8 is associated with a
combination of one or more of the switching elements 12 to 15, each
control point being connected via the matrix 11 to the base
electrodes of the transistors of the switching elements associated
therewith.
Accordingly, if a particular control point is in the "high" state
then the base electrodes of the transistors of the switching
elements with which that particular control point is associated
will also be in the "high" state and if the particular terminal is
in the "low" state, then the base electrodes of the transistors of
the switching elements with which that terminal is associated will
also be in the "low" state. The transistors of the switching
elements are arranged so that each transistor is cut off when its
base electrode is at the "low" state and is conducting when its
base electrode is at the "high" state. Thus, the switching elements
12 to 15 may be regarded as being actuated when the base electrode
of their respective transistors is in the "high" state and the
information provided by the control points 2 to 8 being in either
the "high" or the "low" state may be regarded as actuating
information.
The emitter electrodes of the transistors of the respective
switching elements 12 to 15 are connected to earth via the
collector emitter path of a single transistor TR4 to the base
electrode of which is supplied a control potential in a manner to
be discussed later. The foregoing description of the operation of
the switching elements 12 to 15 assumes that the control potential
at the base of the transistor 16 is such that the transistor 16 in
the "on" state.
Two programme selection switches S1 and S2 are provided. One side
of each of the switches S1 and S2 is connected to the positive
supply line 17. The other side of the switch S1 is connected to an
input of the "and" gate G1, whereas the other side of the switch S2
is connected to an input of the "and" gate G2. Control points 2, 3,
7 and 8 are connected to the other input of the "and" gate G1
whereas control points 3 and 8 are connected to the other input of
the "and" gate G2. The output of the "and" gates G1 and G2 are
connected to separate inputs of the "or" gate G3. The output of the
"or" gate G3 is fed via the terminal 18 to both the gating network
19 and to the timing generator 20. The timing generator 20 consists
of a simple relaxation oscillator denoted generally by the numeral
28 and comprising the silicon controlled switch SCS1, the
resistances 21, 22, 23, 24 and the capacitance 25. The values of
the resistances 21, 22 and 23 and that of the capacitance 25 are so
chosen that the period of the oscillator 28 is approximately 2
minutes, i.e., at 2 minute intervals after initiation of the
oscillator 28, a pulse of short duration is produced at the cathode
of the switch SCS1. The capacitance 25 is bridged by the
collector/emitter path of the transistor 26 which is provided for
disabling or resetting the oscillator 28. If the base electrode of
the transistor 26 is high, the collector/emitter path of the
transistor 26 conducts and short circuits the capacitance 25.
Accordingly, a positive pulse applied via the terminal 27 resets
the oscillator 28 by discharging the capacitance 25. Alternatively,
if the control point 1 is high or the terminal 18 is low, the
oscillator 28 is disabled since capacitance 25 is short
circuited.
The output of the oscillator 28 is fed to an input of the "and"
gate G4, the other input of which is connected to the terminal 18.
Accordingly, if the terminal 18 is high then the oscillator 28
functions and the oscillator output is applied via the gate G4 and
the "or" gate G5 to the reference pulse oscillator 29 for
triggering purposes.
The shaping network 30 is connected to a source of alternating
voltage (not shown) having a frequency of 50 cycles per second to
convert the alternating voltage into a square wave pulse train,
having the same frequency. The output of the network 30 is
continuously supplied to one of the inputs of the "and" gate G6.
The other input of the "and" gate G6 is connected to the output of
the "nor" gate G7 which has two inputs. One of the inputs of the
gate G7 is connected to the terminal 18 and the other input of the
gate G7 is connected to the control point 1. The control point 1
may be connected to earth by operation of the starting switch S3.
If both of the inputs of the "nor" gate G7 are in the "low" state
then the output of the gate G7 is "high" and the square wave output
of the network 30 will be produced at the output of the "and" gate
G6 and will be fed to the input of the reference pulse generator 29
via the "or" gate G5. However, if either or both of the inputs of
the "nor" gate G7 are in the "high" state then the output of the
gate G7 will be "low" and the gate G6 will remain closed thus
disconnecting the output of the shaping network 30 from the
generator 29.
The reference pulse generator 29 comprises a monostable
multivibrator constituted by the transistors TR1 and TR2 which
delivers a positive going fixed width output pulse at the collector
electrode of the transistor TR2 each time the generator is
triggered. In known manner, the width of the output pulse is
determined by the value of the resistance 31 and that of the
capacitance 32. The generator is triggered whenever a triggering
pulse appears at the output of the gate G5, such a triggering pulse
being conveyed to the base electrode of the transistor TR1 via the
differentiating network constituted by the capacitance 33 and the
resistance 34. The pulse 40 of FIG. 2a depicts a typical positive
going reference pulse produced at the collector electrode of the
transistor TR2. The pulse 40 has a duration of 5 milliseconds.
Output pulses from the collector of the transistor TR2 are supplied
to the terminal 27, to the inhibiting circuit 35 and to the base of
the transistor TR3. The transistor TR3 functions as an inverter and
for each reference pulse 40 applied to its base electrode, a
negative going pulse 41, of FIG. 2b, also having a duration of 5
milliseconds is produced at the collector electrode of the
transistor TR3.
The trailing edge 42 of each negative going pulse 41 is employed to
advance the state of the shift register 9. As mentioned, the output
pulse produced at the collector electrode of the transistor TR2 is
also applied to the inhibiting circuit 35. The inhibiting circuit
35 comprises a re-triggable monostable multivibrator including the
transistors TR5 and TR6. The operation of such a monostable
multivibrator is well known and briefly is as follows. The
capacitance 36 is connected to be charged from the positive supply
line 37 via the resistance 38 so that when the apparatus is
switched on, the capacitance 36 becomes charged after approximately
30 milliseconds with the transistor TR6 conducting and the
transistor TR5 cut off. The capacitance 36 is charged to a
predetermined voltage determined by the value of the resistance 39
and the voltage drop across the base emitter path of the transistor
TR6. At the occurrence of a positive going input pulse at the base
of the transistor TR5, the transistor TR5 will conduct thereby
rapidly discharging the capacitance 36 and cutting off the
transistor TR6. At cessation of the input pulse, the capacitance 36
commences to charge again. Whilst the transistor TR6 is conducting,
a positive voltage is supplied to the base electrode of the
transistor TR4 from the base resistance of the transistor TR6
causing the former to conduct but when the transistor TR6 is cut
off, owing to the discharge of the capacitance 36, the voltage
across the emitter resistance 39 falls, causing the transistor TR4
also to be cut off. The values of the resistance 38 and that of the
capacitance 36 are chosen so that for every input pulse applied to
the transistor TR5, the transistor TR6 will remain cut off for 30
milliseconds following each input pulse whilst the capacitance 36
is recharged to the predetermined value. Accordingly, if a further
input pulse is applied before termination of the 30 milliseconds
cut off period (i.e., before the capacitance 36 has sufficiently
recharged for the transistor TR6 to recommence conduction), the
capacitance 36 is discharged once more and the charging process is
repeated.
Accordingly, each time a positive going pulse 40 is produced at the
collector electrode of the transistor TR2, the transistor TR4 is
cut off and the switching elements 12, 13, 14 and 15 are inhibited
for a period commencing with the occurrence of the leading edge of
the pulse 40 which lasts for a period of at least 30 milliseconds
after the termination of the pulse 40. The pulse 43 of FIG. 2c
shows the negative going pulse produced at the base electrode of
the transistor TR4 for every generated reference pulse 40. Whereas
the duration of the pulse 40 is 5 milliseconds, the duration of the
pulse 43 is 35 milliseconds. Both pulses commence at the same
instant. Of course, the pulse 43 denotes the period of time for
which the transistor TR4 is in the cut-off state.
The operation of the circuit of FIG. 1 can be explained in
association with FIG. 3 as follows. With the power supplies to the
circuit switched on and assuming the switch S1 is closed to select
the desired programme, the shift register 9 is in its initial state
with the control point 1 in the "high" state and the remainder of
the control points 2 to 8 in the "low" state. The "high" state of
the control point 1 ensures that the transistor 26 is conducting
and the oscillator 28 is disabled.
Under these conditions, the switch S1, being closed, has no effect
at the initial state of the register 9 although the positive
potential of supply line 17 is connected to an input of the gate
G1, the output of the gate G1 remains "low " because the other
input of the gate G1 (derived from the respective control points)
is in the "low" state. Thus, the output of the "or" gate G3 is
"low" so that the input of the "nor" gate G7 connected to the gate
G3 is "low" and the input of G7 connected to the control point 1 is
"high." Accordingly, the output of the gate G7 is also "low"
ensuring that the "and" gate G6 is closed and the output of the
shaping network 30 cannot be supplied to the reference pulse
generator 29. Since no triggering information is supplied to the
reference pulse generator 29 from either the oscillator 28 or from
the shaping network 30, no timing pulses are produced by the
generator 29 and the shift register 9 remains in the initial
state.
If now the start switch S2 is operated, the programme associated
with the switch S1 is commenced and, in this regard, the wave forms
of FIG. 3 illustrate the wave forms produced at the various parts
of the circuit of FIG. 1 as follows:
FIG. 3a.sub.1 to 3a.sub.8 illustrate respectively the voltage wave
forms present at the control points 1 to 8.
FIG. 3b illustrates the wave forms present at the base electrode of
the transistor TR1.
FIG. 3c illustrates the wave forms present at the collector of the
transistor TR2.
FIG. 3d illustrates the wave forms present at the collector of the
transistor TR3.
FIG. 3e illustrates the wave forms present at the base of the
transistor TR4.
FIG. 3f illustrates the wave forms present at the cathode of the
silicon control rectifier SCS1.
FIG. 3g illustrates the wave forms present at the output of the
gate G6.
With the operation of the start switch S3, the control point 1 is
momentarily shorted to earth and the output of the "nor" gate G7
becomes "high," momentarily opening the gate G6 and allowing the
single pulse 50 of FIG. 3g to be applied via the gate G6 and the
gate G5 to the reference pulse generator 29 resulting in the
differentiated pulse 51 of FIG. 3b being produced at the base of
the transistor TR1. The fixed duration pulse 52 is thus generated
at the collector electrode of the transistor TR2 so that the
inhibiting circuit 35 is triggered and the switching elements 12 to
15 are inhibited from the instant coinciding with the leading edge
of the pulse 52. The inhibition period is illustrated by the pulses
54 of FIG. 3e in which the time t1 is approximately 35
milliseconds. Although the pulse 52 is also applied to the terminal
27, it has no effect since the transistor 26 is already in the "on"
state. The trailing edge of the negative going pulse 53 of FIG. 3d,
generated simultaneously with the pulse 52, advances the shift
register 9 to the second state. It will be appreciated that the
trailing edge of the pulse 53 occurs 5 milliseconds later than the
leading edge of the pulse 52 so that the switching elements 12 to
15 are in a state of inhibition during advancement of the state of
the register 9.
Advancement of the shift register 9 to the second state results in
the "high" state formerly present at the control point 1 to be
transferred to the control point 2 and since the switch S1 is
alreacy closed, both inputs of the gate G1 are now "high," the
output of gates G1 and G3 also become "high" and the output of the
gate G7 becomes "low " immediately closing the gate G6 again to
prevent any further pulses from the network 30 from reaching the
generator 29. Simultaneously, since the terminal 18 is now "high,"
the transistor 26 is cut off and the oscillator 28 commences a
cycle of oscillation. Since also the control point 2 is now in the
"high" state, the base electrodes of the transistors of the
respective switching elements 12 to 15 associated with the control
point 2 are also placed in the "high" state so that the switching
elements concerned will be actuated when the inhibition period
terminates and the transistor TR4 is switched on again.
As mentioned, the period of oscillation of the oscillator 28 is
approximately 2 minutes. Accordingly, the shift register 9 remains
in the second state for an equivalent period. At the end of the 2
minute period, the oscillator 28 produces a positive going output
pulse 55 of short duration at the cathode of the silicon control
switch SCS1. As the terminal 81 is "high," the gate G4 is open and
the pulse 55 is conveyed via the gates G4 and G5 to the input of
the reference pulse generator 29 whereupon another pulse 52 is
generated again resulting in inhibition of the switching elements
12 to 15 and the triggering of the shift register 9 into the third
state.
The process described in relation to the second state is thus
repeated once more except that since the "high" state has been
transferred to the control point 3, the switching elements
associated with the control point 3 are actuated when the second
period of inhibition is completed. At the completion of the third
state of the shift register 9, another pulse 55 is produced by the
oscillator 28, triggering the register 9 into its fourth state.
In the fourth state, the control point 4 becomes "high" and the
gate G1 is closed so that the oscillator 28 is disabled and the
gate G6 is opened so that the output of the network 30 is supplied
to the generator 29.
The fourth state of the register 9 follows a similar pattern of
operations to that of the first or initial state except that the
gate G6 is not closed at the termination of the fourth state
because, unlike the control point 2, the control point 5 is not
connected to an input of the gate G1. Under these conditions, the
oscillator 28 remains disabled and the gate G6 remains open whilst
allowing further pulses recurring at relatively short intervals to
be supplied from the network 30 to the generator 29 thereby
advancing the state of the shift register rapidly to progress
through the fifth state and the sixth state. In the seventh state,
the control point 7 is, of course, "high" so that the gate G6 is
closed and the oscillator 28 is enabled to commence a further cycle
of oscillation. Thus, the seventh state and the eighth state of the
register 9 follow a similar pattern of operations to the second and
third states. At the conclusion of the eighth state, the register 9
is returned to its initial state completing the programme
associated with the switch S1.
It will be appreciated that the reference pulses 52 associated with
the commencement of the fourth, fifth and sixth states of the
register each initiate a period of inhibition of the switching
elements 12 to 15 which is of greater duration than the interval
between those pulses so that the switching elements 12 to 15 remain
inhibited for the total duration of the succession of the relevant
reference pulses and the shift register 9 is therefore "rapidly
advanced" through the fourth, fifth and sixth states without the
switching elements associated with the control points 4, 5 and 6
being actuated for the selected programme under discussion (i.e.,
the programme associated with the switch S1). Of course, during the
programme there is no rapid advance of the shift register 9 in the
case of the second, third, seventh and eighth states of the
register 9. Each of these states has a duration of 2 minutes during
which the combinations of the switching elements 12 to 15
associated with the respective control points 2, 3, 7 and 9 are
actuated.
Now, in the programme associated with the switch S2, the initial
state of the register 9 would be similar to the initial state in
the case of the programme associated with the switch S1. However,
there would be a rapid advancement of the register through the
second state, accompanied by inhibition of the switching elements
12 to 15, the third state would be for a duration of 2 minutes with
the switching elements associated with the control point 3
actuated, there would be rapid advancement through the fourth,
fifth, sixth and seventh states accompanied by inhibition of the
switching elements 12 to 15 and the eighth state would be for a
period of two minutes with the switching elements associated with
the control point 8 actuated.
The switching device diagrammatically illustrated in FIG. 4 has
many parts identical to those of the known switching device of FIG.
1 and such parts are denoted by a similar reference number in each
case. The difference between the switching device of FIG. 4 and
that of FIG. 1 is that the device of FIG. 4 incorporates a bistable
control circuit 60, an "or" gate G8 and an inverter G9. The input
terminals 61 and 62 of the bistable circuit 60 are connected
respectively to the control terminals 2 and 7 and the reset
terminal 63 is connected to the control terminal 1. The output
terminal 64 of the bistable circuit 60 is connected to one of the
inputs of the "or" gate G8, the other input being from the output
of "nor" gate G7. As distinct from FIG. 1, in FIG. 4 the terminal
18 is connected to the timing generator 20 via the diode D2 for the
purpose of disabling the latter and, in addition, in similar manner
and for the same purpose, the output terminal 64 is also connected
to the timing generator 20 via the diode D1, and inverter G9, the
diodes D1 and D2 isolating the terminal 18 from the output of
G9.
The bistable circuit 60 is in the form of a conventional flip-flop
circuit which in a first stable state causes the terminal 64 to be
"low" and in the second stable state causes the terminal 64 to be
"high." In a known manner, application of a "high" voltage to the
terminal 63 sets the bistable circuit 60 in the first state whereas
application of a "high" voltage to the terminal 61 causes the state
of the circuit 60 to be changed from the first state to the second
state and application of a "high" voltage to the terminal 62 causes
the state of the circuit 60 to be changed from the second state to
the first. The bistable circuit 60 is only operative when the
switch S4 is closed. When the circuit 60 is inoperative, the output
terminal 64 is in the "low" state.
When the switch S4 is in the open position, since the bistable
circuit is inoperative the operation of the circuit of FIG. 4 is
substantially the same as the operation of the circuit of FIG. 1 as
described in the specification of Australian Pat. application P.A.
No. 7205/71. The output of the gate G8 is not affected by the
bistable circuit 60 since the terminal 64 is "low" under such
conditions. Accordingly, whenever the start switch S2 is closed,
the programme of switching operations then followed by the circuit
depends upon which of the switches S1 and S2 is closed.
On the other hand, with the switch S4 in the closed position so
that the bistable circuit 60 is operative, the operation of the
circuit of FIG. 4 is no longer substantially the same as that of
FIG. 1. Upon closure of the start switch S3 under such conditions,
the device follows a switching programme in which, regardless of
which of the switches S1 or S2 is closed, there is rapid advance of
the switching device through the states associated with the control
points 2, 3, 4, 5 and 6.
Assuming for instance that the programme selection switch S1 is
closed and that the switch S4 is open to make the bistable circuit
60 inoperative, upon closure of the start switch S3, the programme
of switching operations followed by the device of FIG. 4 would be
substantially the same as the programme of switching operations
described in relation to FIG. 3 of the present specification. If,
upon completion of the programme, the switch S4 is closed to make
the bistable circuit 60 operative and the start switch S3 is closed
once more, the same programme would be repeated except that there
would be a rapid advance through the second, third, fourth, fifth
and sixth states. In other words, there would be a repetition only
of the combination of switching functions associated with the
control points 7 and 8. In the programme followed, the second,
third, fourth, fifth and sixth states would be "skipped."
As an example, if the combination of switching functions associated
with the control points 7 and 8 coincided respectively with the
rinse and the spindry functions in an automatic washing machine
incorporating the device of the invention, then an operator would
be able to readily repeat the rinse and the spindry functions only.
Of course, connection of the terminals 61 and 62 is not restricted
to the control points 2 and 7 respectively but may be to any of the
control terminals appropriate for the register state of which
skipping is desired. Whilst the device of FIG. 4 is a relatively
simple one, the principles of the invention may be incorporated in
a more complicated device of the same general kind, for instance in
a device provided with a shift register having more than eight
states and hence more than eight control points and associated
combinations of switching functions.
The bistable device 60 may be replaced by the bistable control
circuit of FIG. 5 constituted by the "and" gate G13 the inputs of
which are interconnected, as illustrated, with the flip-flop
circuits FF1 and FF2 and the "nand" gates G11 and G12. In FIG. 5,
the terminals 61, 62 and 64 respectively correspond with the
terminals 61, 62 and 64 of FIG. 4.
When the bistable device 60 is replaced by the control circuit of
FIG. 5, the information at the control point 2 is applied via the
terminal 61 to one of the inputs of the "nand" gate G12 and the
other input of the "nand" gate G12 is connected to the output A of
the flip-flop FF1. The output of the "nand" gate G12 is used for
triggering the flip-flop FF2, the output B of which is connected to
one input of the "and" gate G13, the other input of the "and" gate
G13 being also connected to the output A of the flip-flop FF1.
The information of the control point 7 is applied via the terminal
62 to one input of the "nand" gate G11 and also is used to reset
the flip-flop FF2. The other input of the "nand" gate G11 is
connected to the "repeat cycle" switch S5 which, when closed,
applies a positive voltage to that input. The output of the "nand"
gate G11 acts as a trigger source for the flip-flop FF1.
Table 1 following, is a truth table showing the status of the
relevant inputs and outputs of the gates G11, G12 and G13 and the
flip-flops FF1 and FF2 corresponding with the eight states of the
shift register 9 when the switch S5 is open.
TABLE 1 ______________________________________ State of Register 9
1 2 3 4 5 6 7 8 ______________________________________ G 11 INPUT
(a) 0 0 0 0 0 0 1 0 G 11 input (b) 0 0 0 0 0 0 0 0 G 11 OUTPUT 1 1
1 1 1 1 1 1 FF1 OUTPUT A 0 0 0 0 0 0 0 0 G 12 INPUT (a) 0 0 0 0 0 0
0 0 G 12 INPUT (b) 0 1 0 0 0 0 0 0 G 12 OUTPUT 1 1 1 1 1 1 1 1 FF2
OUTPUT B 1 1 1 1 1 1 1 1 G 13 INPUT (a) 0 0 0 0 0 0 0 0 G 13 INPUT
(b) 1 1 1 1 1 1 1 1 G 13 OUTPUT 0 0 0 0 0 0 0 0
______________________________________
From Table 1 it will be appreciated that the input (a) for the gate
G11 (derived from the control point 7) is in the "low" state for
all states of the register 9 except the seventh state whereas the
input (b) for the gate G12 (derived from the control point 2) is in
the "low" state for all states of the register 9 except the second
state. However, since the switch S5 is open, changeover of the
flip-flop FF1 or FF2 cannot occur and the state of the output of
the gate G13 remains in the "low"state during every state of the
register 9. Accordingly, with the switch S5 open, the programme of
switching operations followed by the device depends upon the
setting of the appropriate programme selection switch S1 or S2 and
is not influenced by the control circuit 7. Since the output of the
gate G13 is in the "low" state at the end of the eighth state of
the shift register 9, the shift register 9 is arrested in the
initial state following the eighth state provided that the push
button start switch S3 is open.
Table 2 following is a truth table showing the state of the
relevant input and output of the gates G11, G12 and G13 and the
flip-flops FF1 and FF2 corresponding with the indicated state of
the shift register 9 when the switch S5 is closed.
TABLE 2 ______________________________________ State of Register 9
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
______________________________________ G 11 INPUT (a) 0 0 0 0 0 0 1
0 0 0 0 0 0 0 1 0 G 11 INPUT (b) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 G
11 OUTPUT 1 1 1 1 1 1 0 1 1 1 1 1 1 1 0 1 FF1 OUTPUT A 0 0 0 0 0 0
1 1 1 1 1 1 1 1 0 0 G 12 INPUT (a) 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0
G 12 INPUT (b) 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 G 12 OUTPUT 1 1 1 1
1 1 1 1 1 0 1 1 1 1 1 1 FF 12 OUTPUT B 1 1 1 1 1 1 1 1 1 0 0 0 0 0
0 0 G 13 INPUT (a) 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 G 13 INPUT (b) 1
1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 G 13 OUTPUT 0 0 0 0 0 0 1 1 1 0 0 0 0
0 0 0 ______________________________________
From Table 2, as in the case of Table 1, it will be appreciated
that the input (a) for the gate G11 (derived from the control point
7) is in the "low" state for all states of the register 9 except
the seventh state whereas the input (b) for the gate G12 (derived
from the control point 2), is in the "low" state for all states of
the register 9 except the second state. However, as a result of the
switch S5 being closed, the input (b) of the gate G11 is in the
"high" state thereby resulting in changeover of the state of the
flip-flop FF1 each time the seventh state of the register 9 is
reached. Accordingly, the output A is initially in the "low" state,
the state changing to "high" when the register 9 reaches the
seventh state for the first time, remaining in the "high" state
until the register 9 reaches the seventh state for the second time
whereupon the state of the output A is returned to "low."
Since the output A is applied to the input (a) of the "nand" gate
G12 and also to the input (a) of the gate G 13, changeover of the
flip-flop FF2 and changeover of the state of the output of the gate
G13 becomes possible during the period that the output A of the
flip-flop FF1 is in the "high" state. As indicated by the table 2,
such changeover occurs when the register 9 reaches the seventh
state for the first time, because the flip-flop FF2 is reset by the
signal present at the terminal 62 so that output B of the flip-flop
FF2 is "high." Accordingly, the output of the gate G13 is in the
"high" state during the time that the register 9 is in the seventh
and eighth states for the first time. When the output of the gate
G13 is in the "high" state, the output of the gate G8 will be
"high" so that the square wave output of the network 50 will be
produced at the output of the "and" gate G6 and will be fed to the
input of the reference pulse generator 29 via the "or" gate G5
resulting in rapid advance of the shift register 9. Further, as the
output of the gate G13 is still "high" at termination of the said
eighth state of the register 9, the register 9 is not arrested
during the following initial state of the register 9 but is rapidly
advanced into the second state.
When the register 9 reaches the second state for the second time,
the control point 2 becomes "high" causing the output of the gate
G12 to become "low" and causing the state of the flip-flop FF1 to
change so that the output B becomes "low " and the output of the
gate G13 becomes "low" once more and remains "low" until the shift
register 9 is ultimately arrested when the initial state is reached
for the third time.
From the foregoing description of the operation of the control
circuit of FIG. 5, it will be understood that the control circuit
provides a means of automatically interrupting the course of a
selected programme, repeating a portion of the programme preceding
the interruption and then resuming and completing the selected
programme. For example, in the case of the sequence of operations
associated with Table 2, regardless of which programme has been
selected, the selected programme would be followed through the
first, second, third, fourth, fifth and sixth states of the shift
register 9, the register would then be rapidly advanced through the
seventh and eighth states and again through the first state for the
second time whereupon the selected programme would be repeated
through the second, third, fourth, fifth and sixth states and then
the process would be completed by the performance of the seventh
and eighth states in accordance with the selected programme, the
device being arrested as the first, or initial state was reached
for the third time.
As before, connection of the terminals 61 and 62 is not restricted
respectively to the control points 2 and 7 but may be to any
desired control points. Moreover, the control circuit of FIG. 5 may
be employed associated with devices other than that described in
relation to FIG. 4, for instance, in association with devices
provided with a shift register having more than eight states and
hence more than eight control points and associated combinations or
switching functions.
Referring now to the switching device diagrammatically illustrated
in FIG. 6:
The switching device of FIG. 6 is intended to be employed for
controlling switching operations required in an automatic clothes
washing machine of the kind in which a washing container and an
impeller having a common axis of rotation and capable of being
independently driven by an electric motor are located within a wash
tub to which hot or cold water may be supplied or removed. As is
well known, clothes may be washed and partly dried in such washing
machines by suitably arranging the sequence and/or repetition of
operation including water supply, impeller agitation, water
removal, container spinning, etc.
In FIG. 6, the control points 101, 102, 103, 104, 105, 106, 107 and
108 are each connected to the output of a stage of the shift
register 109 having stages 109A, 109B, 109C etc. The shift register
109 is driven by timing pulses supplied via the terminal 110. The
shift register 109 is of known kind and operates in a known manner.
When the start switch PSS is closed, the mains voltage is supplied
to the power supply circuit X and accordingly appropriate DC
voltages are applied from the power supply circuit X to the
respective DC supply lines (not shown). In addition, mains voltage
is supplied to the mains supply line Y. When the shift register is
in an initial state, with the switch PSS closed, the control point
101 is in the "high" state with the remaining control points all at
the "low" state.
At the occurrence of the first timing pulse supplied via the
terminal 110, the shift register 109 is advanced so that the
control point 102 goes to the "high" state, the control point 101
goes to the "low" state and terminals 103 to 108 remain in the
"low" state. This condition remains until the occurrence of the
next timing pulse whereupon the control point 103 goes to the
"high" state and the control point 102 returns to the "low" state,
the control point 101 and control points 104 to 108 remain in the
"low" state. The process is continued with the "high" state being
transferred sequentially along the plurality of control points 101
to 108 at the occurrence of successive timing pulses. When the
control point 8 is at the "high" state, the next succeeding timing
pulse results in the shift register 9 being returned to its initial
state and simultaneously the start switch PSS is returned to the
open condition owing to the energisation of the solenoid SOL by the
operation of the reset circuit RC when the state at control point 8
changes from the "high" state to the "low" state.
The control points 101 to 108 are connected via the matrix 111 to
one or more of the switching elements SE1, SE2, SE3 and SE4, SE5.
The switching elements SE1, SE2, SE3 and SE4, SE5 are each in the
form of a transistor provided with a load in its collector circuit.
The load of the individual switching elements may be in the form of
a relay, a lamp, a resistance, a solenoid, etc. However, in the
present instance, the load of the switching element SE1 is in the
form of solenoid for actuating a cold water supply valve for
supplying cold water to the washtub of the machine, the load of the
switching elements SE2 is a similar solenoid for actuating a hot
water supply valve, the load of the switching element SE3 is the
winding of a relay RL1, the load of the switching elements SE4 and
SE5 are each in the form of a solenoid for respectively actuating a
mechanism for causing the impeller of the machine to "agitate" or
actuating a mechanism for causing the washing container to spin,
provided that the motor M is running.
The connections from the control points 101 to 108 to the switching
elements SE1 to SE5 are such that each of the control points is
associated with a combination of one or more of the switching
elements SE1 to SE5, each control point being connected directly or
indirectly to the base electrodes of the transistors of the
switching elements associated therewith.
Accordingly, if a particular control point is in the "high" state
then depending upon programme selection, the control electrodes of
the transistors of thr switching elements with which that
particular control point is associated will also be in the "high"
state and if the particular point is in the "low" state, then the
electrodes of the transistors of the switching elements with which
that control point is associated will also be in the "low" state.
The transistors of the switching elements are arranged so that each
transistor is cut off when its base electrode is at the "low" state
and is conducting when its base electrode is at the "high" state.
Thus, the switching elements SE1 to SE5 may be regarded as being
actuated when their respective base electrodes are in the "high"
state and the information provided by the control points 101-102
being in either the "high" or the "low" state may be regarded as
actuating information.
A programme selection means PSM is provided which includes a switch
assembly of the kind in which the two push-button operated
switches, S101 and S102, are mechanically interlocked with each
other so that only one switch of the assembly can remain in the
closed condition at a given time. The switch assembly also
incorporates a push-button, hereinafter referred to as the blank
push-button, which is not capable of closing any of the switches
but is coupled with the mechanical interlocking mechanism in such a
manner that, if operated, either switch of the assembly occupying
the closed condition is opened.
The programme selection means PSM also includes the auxiliary
push-button operated switches S103, S104 and S105 which are
mechanically independent of the pushbutton switch assembly of which
the switches S101 and S102 form part. Switch S106 is a further
auxiliary pushbutton button operated switch which may, or may not
form part of the programme selection means PSM upon the
requirements. One side of each of the switches S101 to S106 is
connected to the positive supply line 117. The other side of the
switch S101 is connected to an input of the "nand" gate G102, the
other side of the switch S102 is connected to an input of the
"nand" gate G104, the other side of the switch S103 is connected to
an input of the "nand" gate G103, the other side of the switch S104
is connected to an input of the "or" gate G107 and also to an input
of the "and" gate G108 via the inverter INV1, the other side of the
switch S105 is connected to the other input of the "or" gate G107
whereas the other side of the `hold` switch S106 is connected via
the inverter INV3 to an input of the "nand" gate G101, to an input
of the "and" gate G112 and to an input of the "and" gate G115.
The pulse supply means PG comprises a relaxation oscillator 128
constituted by the silicon controlled switch SCS101, the resistors
121, 122, 123 and 124, and the capacitances 125 and 126. The
oscillator 128 is capable of being operated in any one of two
alternative modes, the particular mode of operation depending upon
the state of conductivity of the transistor TR102. When the
transistor TR102 is non-conductive, the period of oscillation is
determined by the values of the resistances 121, 122 and 123, and
by the resultant values of the series combination of the
capacitances 125 and 126. The selection of the values of the
respective components is such that in this mode of operation the
period of oscillation of the oscillator 128 is approximately 5
milliseconds. Alternatively, when the transistor TR102 is in the
conductive state, the period of oscillation of the oscillator 128
is determined by the value of the resistances 121, 122, and 123,
and by the value of the capacitance 125. The respective components
are selected so that in this mode of operation the period of
oscillation is approximately 30 seconds. Thus, the ratio of the
period of oscillation in one mode to the period of oscillation to
the other mode is of the order of 1:6,000. In either mode of
operation, a positive going output pulse of short duration is
produced across the resistance 124 for every cycle of oscillation.
The transistor TR102 is non-conductive when its base electrode is
at more potential, or in other words when the base potential is
"low." The transistor TR102 is rendered conductive by application
to the electrode of a positive potential greater than approximately
0.6 volts, or in other words when the base potential is "high."
The series combination of the capacitances 125 and 126 is shunted
by the collector-emitter path of the control transistor TR101.
Application of a "high" voltage to the base of the transistor TR101
causes the transistor to conduct, short-circuiting the series
combination of the capacitances 125 and 126 and thereby inhibiting
operation of the oscillator 128 altogether. On the other hand,
application of a "low" voltage to the base of the transistor TR101
ensures that the transistor is non-conductive and that the
oscillator 128 operates in one mode of operation or the other
depending upon the state of conductivity of the transistor TR102
and the presence of suitable operating potentials.
The output pulses of the pulse supply means PG are derived from
across the resistance 124 and supplied to the divider DIV. The
output pulses of which are fed to the terminal 110 and serve as
timing pulses for triggering the shift register 109. The divider
DIV is in the form of an eight-bit shift register which produces an
output pulse for every eighth input pulse.
A comparison means C.M. includes the "nand" gates G102, G103 and
G104 the outputs of which are connected to the timing line TL, the
state of the timing line T.L. determines the mode of operation of
the oscillator 128.
The operation of the switching device of FIG. 4 will now be
described in conjunction with the chart of FIG. 7 which sets out in
tabular form a basic programme and modifications of that basic
programme for different settings of the programme selection
means.
The basic programme is followed when the start button PSS is closed
provided the `blank` push-button has previously been selected and
none of the switches S103, S104, S105 and S106 are selected. The
`blank` push-buttons may conveniently be marked `superwash` and the
word `superwash` is employed in the chart of FIG. 7 to denote this
basic programme. In the chart of FIG. 7 there are eight columns,
numbered accordingly, which coincide with the eight states of the
shift register 109. As indicated in each column, certain events are
carried out during each state of the basic programme `superwash,`
the activities in question are each indicated in the column
concerned and for the basic programme `superwash` an asterisk
appears in each column to show that every event is carried out in
the course of the basic programme. For other programmes or
modifications indicated in the chart of FIG. 7, asterisks are
omitted in certain columns alongside the indicated programme or
modification indicating that the particular event related to the
column is omitted as the shift register 109 advances through the
eight states.
In following the basic programme `superwash,` upon closure of the
switch PSS under these conditions, the shift register 109 is in its
initial state and accordingly the control points 101 is "high," the
remaining control points 102-108 being "low."
Since neither of the switches S101 and S102 are closed, the timing
line TL is in the "high" state ensuring that the transistor TR102
is conductive so that the oscillator 128 is set for that mode of
operation for producing an output pulse every 30 seconds provided
the transistor TR101 is simultaneously non-conductive. However, the
state of conductivity of transistor TR101 depends, inter alia, upon
the condition of the water level switch WLS. The water level switch
WLS is associated with the wash tub of the machine and produces a
"high" at one of the inputs of each of the "and" gates G105, G106
and G113 whenever the level of the water in the wash tub is below a
predetermined `full` level and produces a "low" at those inputs of
the gates G105, G106 and G113 whenever the water in the wash tub
has reached the predetermined `full` level. If the water level in
the machine wash tub is below the `full` level when the shift
register is in the initial state, the "high" produced by the switch
WLS results in a "high" being produced at the output of the "and"
gate G114 provided the timing line TL is also "high" thereby
preventing oscillation of the oscillator 128. Thus, the shift
register must remain in the initial state so long as the water
level of the machine is below the `full` level. During the initial
state of the shift register 109 when performing the basic programme
with the water level of the machine wash tub below the `full`
level, since the control point 101 is in the "high" state the
switching elements SE1 and SE4 are actuated but the switching
elements SE2, SE3 and SE5 are not actuated. Switching element SE1
is actuated via the "and" gate G105 and the "or" gate G109 and
since the switching element SE1 is actuated, the solenoid forming
the load is energised thereby opening the `cold water` supply valve
for supplying cold water to the machine wash tub. Accordingly, the
wash tub commences to fill. Even through the switching element SE4
is actuated, the actuation has no effect since the motor M is not
energised, the contacts of the relay RL1 being open because the
switching element SE3 is not actuated.
Once the water level in the machine wash tub has reached the `full`
level, changeover of the switch WLS results in a "low" being
applied to an input of each of the "and" gates G105, G106 and G113.
Accordingly, the "and" gate G106 is closed so that actuating
information from the control point 101 is no longer applied to the
switching element SE1 and the cold water supply valve is closed.
The closure of the gate G106 also results in the output of the "or"
gate G111 going "low" so that via the inverter INV4, the "nand"
gate G101 and the "and" gate 104, the transistor TR101 is rendered
non-conductive and via the inverter INV5 and the "and" gate G112,
the switching element SE3 is actuated so that the contacts of the
relay RL1 are closed and the motor M is energised. As the switching
element SE4 is already actuated, the impeller of the washing
machine commences to agitate. Transistor TR101 being rendered
conductive, permits the oscillator 128 to commence oscillation and
produce an output pulse every 30 seconds and since the output of
the oscillator 128 is connected to the shift register 109 via the
divider DIV, a timing pulse is supplied to the shift register 109
four minutes after the oscillator 128 has commenced to oscillate
thereby triggering the shift register 109 into the second state
whereupon the control point 101 goes "low" and the control point
102 goes "high."
In theory, similar switching operations are carried out for the
second state of the shift register 109 as in the initial state
whilst performing the basic programme under discussion. However, in
practice, as the water level in the machine wash tub has already
reached the predetermined `full` level required for changeover of
the switch WLS, the state of affairs existing during the latter
portion of the initial state are continued, i.e. the output of the
"or" gate G111 is "low" so that the switching elements SE3 and SE4
are still actuated. Accordingly, throughout the second state, the
impeller continues to agitate whereas the transistor TR101 remains
non-conductive so that the oscillator 128 continues to oscillate
and the divider DIV produces another timing pulse four minutes
after the commencement of the second state which triggers the shift
register 109 into the third state whereupon the control point 102
goes "low" and the control point 103 goes "high."
Again, in theory, similar switching operations are carried out for
the third state of the shift register 109 as in the initial state
during performance of the basic programme under discussion. Again
however, in practice, as the water level in the machine wash tub
has already reached the predetermined level required for changeover
of the switch WLS, the state of affairs existing during the latter
portion of the initial state, and existing throughout the second
state are continued, i.e., the output of the "or" gate G111 is low
so that the switching elements SE3 and SE4 are still actuated.
Accordingly, during the third state the impeller continues to
agitate whereas the oscillator 128 continues to oscillate and the
divider DIV produces another timing pulse four minutes after the
commencement of the third state which triggers the shift register
109 into the fourth state whereupon the control point 103 goes
"low" and the control point 104 goes "high."
Before commencing a description of the operations associated with
the fourth state of the shift register 109 during performance of
the basic programme, it should be mentioned that the motor M is
arranged to drive a water pump whenever the motor is running.
Moreover, the mechanism for either causing the impeller of the
machine to agitate or causing the washing container to "spin"
provided that the motor is running is so arranged that when neither
the switching elements SE4 and SE5 are actuated, the water pump is
connected to pump water out of the machine wash tub.
As there are no connections between the control point 104 and the
matrix 111 then the change of state of the shift register 109 from
the third state to the fourth state results in the switching
element SE4 being no longer actuated. However, the timing line TL
remains in the "high" state and the output of the "or" gate G111 is
still "low" so that other conditions of the third state continue in
the fourth state in that the switching element SE3 remains actuated
so that the motor M continues to be energised and in that the
transistor TR101 remains non-conductive and the transistor TR102
remains conductive. Thus, the oscillator 128 continues to oscillate
in the mode producing an output pulse every 30 seconds so that 4
minutes after the commencement of the fourth state the divider DIV
produces a further timing pulse which triggers the shift register
109 into the fifth state whereupon the control point 104 goes "low"
and the control point 105 goes "high." Of course, during the fourth
state, since neither of the switching elements SE4 and SE5 are
actuated, the water pump driven by the motor M is connected to pump
water out of the machine wash tub whilst the impeller of the
machine remains stationary. Owing to the removal of water from the
machine wash tub, the switch WLS returns to the condition under
which it produces a "high" inter alia at one of the inputs of the
gate G113.
In the fifth state, a "high" being produced at the control point
105 supplies a "high" to the base of the transistor incorporated in
the switching element SE5 via the "and" gate G113 which is open and
the switching element SE5 is therefore actuated. Since the timing
line TL is still "high" and since the output of the "or" gate G111
is low, the oscillator 128 continues to oscillate in the mode
producing output pulses every 30 seconds and the switching element
SE3 remains actuated so that the motor M continues to be energised.
Actuation of the switching element SE5 thus results in the impeller
of the washing machine being caused to spin but the water is no
longer pumped from the wash tub. Again, four minutes after the
commencement of the fifth state, the divider DIV produces a timing
pulse triggering the shift register into its sixth state whereupon
the control point 105 goes "low" and the control point 106 goes
"high."
The operation of the device for the sixth state is similar to that
of the first state during performance of the basic programme
although the information from the control point 106 reaches the
related switching elements via a different series of gates. Again,
since the switch WLS supplies a "high," the switching element SE1
is actuated so that water is supplied to the machine wash tub until
the predetermined `full` level is reached whilst simultaneously the
transistor TR101 is rendered conductive thereby rendering the
oscillator 128 inoperative. Again, when the water level in the
machine wash tub has reached the `full` level, the switch WLS
delivers a "low" so that the switching element SE1 ceases to be
actuated and a "low" is produced at the output of the "or" gate
G111 so that the switching element SE3 is actuated and the motor M
is energised whereupon the switching element SE4 being actuated
from the control point 106 causes the impeller of the machine to
agitate. In addition, when the output of the "or" gate G111 goes
"low" the transistor TR101 is rendered non-conductive and the
oscillator 128 commences to oscillate. Four minutes after the
commencement of oscillation, the divider DIV produces a further
timing pulse triggering the shift register 109 into the seventh
state whereupon the control point 106 becomes "low" and the control
point 107 becomes "high."
The operation of the device for the seventh state is similar to
that of the fourth state during performance of the basic programme,
the switching element SE3 being actuated whilst the switching
elements SE4 and SE5 are not actuated so that the water pump driven
by the motor M removes water from the machine wash tub once more
whilst the transistor TR101 remains non-conductive so that the
oscillator continues to oscillate and four minutes after the
commencement of the seventh state the divider DIV supplies a
further timing pulse triggering the shift register into the eighth
state whereupon the control point 107 goes "low" and the control
point 108 goes "high."
The operation of the device during the eight state is similar to
that of the fourth state during performance of the basic programme,
the switching elements SE3 and SE5 being actuated so that the
washing container is caused to spin whilst the transistor TR101
remains nonconductive so that the oscillator 128 continues to
oscillate in the mode producing output pulses each 30 seconds and 4
minutes after the commencement of the eighth state, the divider DIV
supplies a further timing pulse triggering the shift register 109
into the initial state once more whereupon the control point 108
goes "low" and the control point 101 goes "high". However, upon
transition of the control point 108 from the "high" state to the
"low" state, the differentiating network constituted by the
resistance 127 and the capacitance 130 in the reset circuit RC
causes the normally conducting transistor TR103 to be momentarily
cut-off and the momentary increase of the collector voltage of the
transistor TR103 causes the transistor TR104 to conduct heavily for
a short period energising the solenoid SOL and releasing the switch
PSS from the closed condition thus removing the mains power supply
voltage from the mains line Y and from the power supply X.
Instead of selecting the basic programme "Superwash," a secondary
programme may be selected such as `Normal wash` or `Spin Dry.` If
either of these secondary programmes are selected, then upon
closure of the start switch PSS, the basic programme is followed
except that the basic programme is modified by the shift register
109 being rapidly advanced through certain states during the
performance of the programme and the switching elements of the
respective combinations associated with the states through which
the shift register is rapidly advanced are still actuated. For some
of the combinations of switching elements through which the shift
register 109 is rapidly advanced, one or more of the switching
elements are rendered ineffectively by the state of the relay RL1,
the contacts of which thus set as a cancelling switch, producing
cancellation of the function that would otherwise occur. Those
switching elements not so rendered ineffective control functions,
the occurrence of which is of such short duration that they may be
disregarded for practical purposes.
From the chart of FIG. 7, it can be seen that in performance of the
secondary programme `Normal Wash,` the basic programme is followed
except that the shift register 109 is rapidly advanced through the
second state. The result of selecting `Normal Wash` instead of
`Super Wash` is that after the filling of the machine wash tub to
the predetermined level, agitation of the impeller is for a total
period of only 8 minutes instead of for a total period of 12
minutes.
Rapid advancement of the shift register 109 through the second
state during performance of the secondary programme `Normal Wash`
occurs as follows:
Upon closure of the switch PSS, after previously selecting the
`Normal Wash` push-button S102, without any of the switches S103 to
S106 being selected, power supplies are supplied to the device as
previously described, the shift register 109 being in the initial
state with the control point 101 being "high." As mentioned, the
initial state of the register 109 during performance of the
secondary programme `Normal Wash` coincides with the initial state
of the register in the basic programme `Super Wash` and at the end
of the initial state, the control point 101 goes "low" and control
point 102 goes "high" as the second state commences. The "high"
present at the control point 102 is applied to one input of the
"nand" gate G104, the other input of which is also "high" since the
switch S102 is closed. Accordingly, the output of the "nand" gate
G104 is "low" making the timing line TL also "low" thereby
rendering the transistor TR102 non-conductive and ensuring that the
transistor TR101 is also non-conductive. Thus, the oscillator 128
commences to oscillate in the mode in which an output pulse is
produced every 5 milliseconds so that 40 milliseconds after the
commencement of oscillation, the divider DIV produces a timing
pulse which advances the shift register into the third state
whereupon the control point 102 goes "low" and the control point
103 goes "high." During the second state, since the timing line TL
is in the "low" state, the output of the "and" gate G112 is also
"low" and the switching element SE3 is not actuated and hence the
contacts of the relay RL1 are open. Of course, since the contacts
of the relay RL1 are open, the motor M is not energised and
although the switching element SE4 is actuated, such actuation is
rendered ineffective owing to the cancelling effect produced by
non-actuation of the switching element SE3. In addition, the
switching element SE1 is actuated but since actuation is for such a
short period (40 milliseconds) its actuation may be ignored for
practical purposes.
The third, fourth, fifth, sixth, seventh and eighth states of the
register 109 in the performance of the secondary programme `Normal
Wash` coincide with the third, fourth, fifth, sixth, seventh and
eighth states respectively of the performance of the basic
programme `Super Wash.`
From the chart of FIG. 7, it can be seen that in performance of the
secondary programme `Spin Dry,` the basic programme is followed
except that the shift register 109 is rapidly advanced through the
first six states. The result of selecting `Spin Dry` instead of
`Super Wash` is that the function of filling and agitating
associated with the first, second and third states, the pumping
associated with the fourth state, the spinning associated with the
fifth state and the filling and agitating associated with the sixth
state do not occur. The function of pumping associated with the
seventh state and that of spinning associated with the eighth state
are however carried out.
The selection of the secondary programme `Spin Dry` is accomplished
by selection of the switch S101, without selection of any of the
switches S103 to S106 and in the performance of this secondary
programme it will be appreciated that during the initial, second,
third, fourth, fifth and sixth states of the shift register, the
timing line TL is "low" since S104 is closed and that a "high" is
present at both inputs of the "nand" gate G102. As the timing line
TL goes "low," the oscillator 128 is operative and oscillates in
that mode producing output pulses each 5 milliseconds so that the
shift register is advanced by timing pulses supplied each 40
milliseconds to the terminal 110. Simultaneously, as the timing
line TL is "low" the output of the "and" gate G112 is also "low"
and the switching element SE3 is not actuated and the motor M is
not energised. Thus, the agitating function associated with the
initial, second, third and sixth states, the pumping function
associated with the fourth state and the spinning function
associated with the fifth state do not occur even though the
switching element SE4 is actuated in the initial, second, third and
sixth states and the switching element SE5 is actuated in the fifth
state. Although actuation of the switching element SE1 occurs
during the initial, second, third and sixth states, the
energisation of the solenoid controlling the cold water supply
valve is of such short duration that it can be neglected for
practical purposes. Upon termination of the sixth state, the
control point 106 goes "low" and the control point 107 goes "high."
Thus, the seventh state commences and coincides with the seventh
state of the basic programme. Similarly, the eighth state of the
register, identical with the eighth state of the basic programme is
carried out and the register is ultimately triggered into the
initial state once more, whereupon the shift register is arrested
by the release of the switch PSS upon transition from the eighth to
the initial state.
Regardless of whether a basic programme or a secondary programme is
selected, the programme in question may be modified, as desired, by
the additional selection of one or more of the auxiliary
push-button operated switches S103 to S106. The effect of selecting
any of the switches S103 to S105 is to alter the combination of
switching elements associated with one or more states of the shift
register 109 during performance of the selected basic or secondary
programme. The chart illustrated in FIG. 6, of the accompanying
drawings illustrates the modifications to the basic programme
`Super Wash` produced by selection of one or more of the switches
S103 to S105.
The programme illustrated in relation to `Super Wash` in FIG. 8, of
course, coincides with that illustrated in FIG. 7 since the
conditions are those in which none of the auxiliary switches S103
to S105 are selected. The programme illustrated in relation to
`Super Wash` + `Hot Wash` is produced by the combined selection of
the `Super Wash` push-button and the `Hot Wash` push-button (S104).
In this event, the modified basic programme followed is identical
with that for the basic programme `Super Wash` except that in the
initial, second and third states, the switching element SE1 is
actuated in the basic programme `Super Wash` whereas the switching
element SE2 is actuated in lieu thereof in the modified basic
programme. This change of combination of switching elements is
brought about for the states in question by the "and" gate G108
being disabled and by the "and" gate G110 being enabled by the
"high" produced by the switch S104 respectively supplied via the
inverter INV1 to an input of the gate G108 and via the "or" gate
G107 to an input of the gate G110. It will be appreciated that
actuation of the switching element SE2 in lieu of the switching
element SE1 results in energisation of the solenoid for opening the
hot water supply valve instead of energisation of the solenoid for
opening the cold water supply valve. Similarly, the programme
illustrated in relation to `Super Wash + Warm Wash` is produced by
the simultaneous selection of the `Super Wash` push-button and the
`Warm Wash` push-button (S105). In this event, the modified basic
programme followed is identical with that for the basic programme
`Super Wash` except that in the initial, second and third states of
the basic programme, the switching element SE1 alone is actuated
for water filling whereas in the modified basic programme the
switching element SE2 as well as the switching element SE1 is
actuated. This change of combination of switching elements is
brought about for the states in question since "and" gate G110 is
enabled by application of a "high" from the switch S105 via the
"or" gate G107.
The programme illustrated in relation to `Super Wash + Drip Dry` is
produced by the simultaneous selection of the `Super Wash`
push-button and the `Drip Dry` pushbutton (S103). In this event,
the modified basic programme followed is identical with that for
the basic programme `Super Wash` except that the `spin` function
associated with the eighth state os imitted, the shift register 109
being rapidly advanced through the eighth state since the "high"
produced at the control point 108 during the eighth state, in
combination with the "high" produced by the switch S103 results in
a "low" at the output of the "nand" gate G103 during the state in
question thereby making the time line TL "low."
The consequences will be evident to persons skilled in the art if
there is a simultaneous selection of `Super Wash` and two of the
auxiliary switches S103 to S105, for example, `Super Wash + Hot
Wash + Drip Dry.`
The `hold` switch S106 may be selected, if desired, at any part of
a basic or secondary programme, mofidifed or otherwise. The
selection of the `hold` switch S106 results in a "low" being
produced at the output of the inverter INV, which disables the
"nand" gate G101 thus inhibiting the oscillator 128 altogether,
disables the "and" gate G112 so that the switching element SE3
cannot remain in the actuated condition and thus the motor M cannot
remain energised, and disables the "and" gate G115 thereby
inhibiting any actuation of either of the switching elements SE1
and SE2.
Thus, selection of the `hold` switch S106 arrests the performance
of any function regardless of which state of the register is
occupied at the time of selection. Return of the switch S106 to the
"open" state resotres the switching device to the condition
existing at the time of selection thereby permitting the remainder
of the programme to be completed.
The switching device diagrammatically illustrated in FIG. 9 has
many parts identical to those of the known switching device of FIG.
6 and such parts are denoted by a similar reference numeral or
letter in each case. The difference between the switching device of
FIG. 9 and that of FIG. 6 is that the switching device of FIG. 9
incorporates a programme override circuit POC having separate
trigger input terminals 212 and 213, a control input terminal 214,
an output terminal 210 and an auxiliary output terminal 211. The
output terminal 210 is connected to the timing line TL, the input
terminal 212 is connected to the control point 108, the input
terminal 213, is connected to the control point 106 and the control
input terminal 214 is connected to earth via a resistance 215 and
to a source of positive potential (not shown) via the switch S200.
In addition, the electrode of the capacitance 130 remote from the
base of the transistor TR103 and the input of the "nand" gate G103
instead of being directly connected to the control point 108 as in
FIG. 6 are instead connected to the output of the "and" gate G203,
one input (b) of which is connected to the control point 108 and
the other input (a) of which is connected to the output of the
"nand" gate G202. One input (a) of the "nand" gate G202 is
connected to the auxiliary output terminal 211 of the circuit POC
whereas the other input (b) of the "nand" gate G202 is connected to
the junction of the resistance 215 with the switch S200.
The programme override circuit POC is constituted by two identical
JK master-slave flip-flops FF201 and FF202 and a "nand" gate G201.
The flip-flops FF201 and FF202 are, in the present instance, in the
form of a Dual JK Master-Slave Flip-Flop Philips type FJJ 121/7473,
the operation of which is well known and which is provided in a
single package. For convenience of reference, the same symbols are
employed in FIG. 9 as those used in published data information on
the Philips type FJJ 121/7473, i.e., the symbols T1, J1, K1, Q1 and
Q2 respectively denote the trigger input, J input, K input, and the
complementary output of the flip-flop FF201 whereas the symbols T2,
J2, K2, Q3 and Q4 respectively denote the trigger input, J input, K
input and complementary outputs of the flip-flop FF202. As is
known, the operation of a flip-flop of a Philips type FJJ 121/7473
is as indicated by the function table set out below as Table 3.
TABLE 3 ______________________________________ t n t n + 1 J K Q1
(Q3) ______________________________________ L L Q n L H L H L H H H
Q n ______________________________________ H = High State L = Low
State
In Table 3, the column indicated as tn shows alternative states of
the J and K inputs at a time tn i.e. at the occurrence of a trigger
pulse applied to the trigger input whereas the column indicated as
tn + 1 shows the resultant output produced at the Q1 (or Q3) output
at the occurrence of the next succeeding trigger pulse. The symbol
Qn indicates that the Q1 (or Q3) output produced is the same as the
Q1 (or Q3) output existing at the time tn whereas the symbol Qn
indicates that the Q1 (or Q3) output produced is the reciprocal of
the Q1 (or Q3) output existing at the time tn. Of course, although
not indicated in table 3, the Q2 (or Q4) outout is the reciprocal
of the Q1 (or Q3) output at any given time.
The flip-flops FF201 and FF202 are interconnected with each other
and with the "nand" gate G201 and connections to respective input
and output terminals of the circuit POC exist. The trigger input
terminals 212 and 213 are respectively connected to the trigger
inputs T1 and T2. The control input terminal 214 is connected to
the J1 input of the flip-flop FF201. The K1 and K2 inputs of the
flip-flops FF201 and FF201 respectively are both connected to a
positive potential. The Q1 output of the flip-flop FF201 is
connected to the J2 input of the flip-flop FF202 and to an input
(a) of the "nand" gate G201. The output Q2 of the flip-flop FF201
is connected to the auxiliary output terminal 211. The Q4 output of
the flip-flop FF202 is connected to the other input (b) of the
"nand" gate G201 and the output of the "nand" gate G201 is
connected to the output terminal 210 of the circuit POC.
Table 4 following is a truth table showing the states of the
relevant parts of the programme override circuit POC and at
relevant inputs and outputs of the gate G202 and G203 corresponding
with eight states of the shift register 109 when the switch S200 is
open.
TABLE 4 ______________________________________ State of Shift
Initially 1 2 3 4 5 6 7 8 Register 109
______________________________________ Terminal 214/J1 0 0 0 0 0 0
0 0 0 Terminal 212/T1 0 0 0 0 0 0 0 0 1 Q1 0 0 0 0 0 0 0 0 0 Q2 1 1
1 1 1 1 1 1 1 J2 0 0 0 0 0 0 0 0 0 T2 0 0 0 0 0 0 1 0 0 Q3 0 0 0 0
0 0 0 0 0 Q4 1 1 1 1 1 1 1 1 1 G 201 INPUT (a) 0 0 0 0 0 0 0 0 0 G
201 INPUT (b) 1 1 1 1 1 1 1 1 1 G 201 OUTPUT 1 1 1 1 1 1 1 1 1 G
202 INPUT (a) 1 1 1 1 1 1 1 1 1 G 202 INPUT (b) 0 0 0 0 0 0 0 0 0 G
202 OUTPUT (a) 1 1 1 1 1 1 1 1 1 G 203 INPUT (a) 1 1 1 1 1 1 1 1 1
G 203 INPUT (b) 0 0 0 0 0 0 0 0 1 G 203 OUTPUT 0 0 0 0 0 0 0 0 1
______________________________________ 1 = HIGH STATE 0 = LOW
STATE
From Table 4 in association with Table 3, it will be appreciated
that since the J1 input of the flip-flop FF201 is "low" and the K1
input is "high," then the terminal Q1 will be "low" and the output
terminal 210 will be "high" for every state of the shift register
109 so long as the switch S200 is open. Thus, the timing line TL is
not rendered "low" due to the operation of the gate G201.
Accordingly, with the switch S200 open, the programme of switching
operations followed by the device depends upon the setting of the
appropriate push-button or buttons of the programme selection means
PSM and is not influenced by the programme override circuit POC.
However, since the Q2 output of the flip-flop FF201 is in the
"high" state and the switch S200 is open, making the input (b) of
the "nand" gate G202 "low" then the output of the "nand" gate G202
is "high" opening the gate G203 to actuation information produced
at the control point 108. Accordingly, the output of the gate G203
goes "high" in the eighth state of the shift register 109 and at
the transition from the eighth state to the initial state, the
shift register 109 is arrested by the release of the switch PSS as
previously described.
Table 5 following is a truth table showing the states of the
relevant parts of the programme override circuit POC and at
relevant inputs and outputs of the gates G202 and G203
corresponding with indicated states of the shift register 109 when
the switch S200 is closed.
TABLE 5
__________________________________________________________________________
State of Shift Initially 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Register
109
__________________________________________________________________________
Terminal 214/J1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Terminal 212/T1 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Q1 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1
1 Q2 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 J2 0 0 0 0 0 0 0 0 0 1 1 1 1
1 1 1 1 T2 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 Q3 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 1 1 Q4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 G201 INPUT (a) 0
0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 G201 INPUT (b) 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 0 0 G201 OUTPUT 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 1 1 G202
OUTPUT (a) 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 G202 INPUT (b) 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 G202 OUTPUT 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1
1 1 G203 INPUT (a) 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 G203 INPUT (b)
0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 G203 OUTPUT 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 1
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1 = High State 0 = Low State
From the Table 5, it will be appreciated that during the first
eight states of the shift register 109, the output of the gate G201
and hence the output terminal 201 is "high" and thus the timing
line TL is not made "low" due to the operation of the circuit POC
during these first eight states. Accordingly, with the switch S200
closed, the programme of switching operations followed by the
device depends upon the setting of the appropriate pushbutton or
buttons of the programme selection means PSM and is not influenced
by the programme override circuit POC during these first eight
states. However, with the switch S200 closed, both inputs of the
gate G202 are "high" during the first eight states of the shift
register 109 so that the output of the gate G202 is "low" and the
gate G203 is closed to actuation information produced at the
control point 108. Thus, the shift register 109 is not arrested
upon termination of the eighth state but commences a second,
eight-state cycle. In addition, upon transition from the eighth
state of the first cycle to the initial state of the second cycle,
the output Q1 of the flip-flop FF201 changes from "low" to "high"
so that both inputs of the "nand" gate G201 are now "high" and the
output of the "nand" gate G201 goes "low" making the timing line TL
"low" thereby rendering the transistor TR102 non-conductive and
ensuring that the transistor TR101 is also non-conductive. Thus,
the oscillator 128 commences to oscillate in the mode in which an
output pulse is produced every 5 milliseconds and the shift
register 109 is rapidly advanced through the first, second, third,
fourth, fifth and sixth states of the second, eight-state cycle. At
the end of the sixth state, the flip-flop FF202 changes state as
the control point 106 goes from "high" to "low" and as a result the
output terminal Q4 goes "low" making the output of the "nand" gate
"high" once more so that the timing line TL is no longer made "low"
due to the circuit POC and the seventh and eighth states of the
second cycle of the shift register are carried out in accordance
with the selected programme.
Of course, with the change of state of the flip-flop FF201 at the
end of the eighth state of the first cycle, the output Q2 became,
"low" and, since the input (b) of the "nand" gate G202 is "high" as
a result of the switch S200 being closed the output of the gate
G202 is "high" rendering the "and" gate G203 open for actuation
information to be passed by the gate G203 so that when the end of
the eighth state of the second cycle of the shift register 109 is
reached, the shift register 109 is arrested in the manner
previously described.
In practice, assuming the "Super-Wash" programme had been selected
and the switch S200 had been closed, then after pressing the start
switch PSS, the "Super-Wash" programme in accordance with the chart
of FIG. 5 would be performed followed by repetition of the "pump"
and "spin" functions whereupon the shift register would be
arrested.
Again, connection of the terminals 211 and 213 is not restricted to
the control points 108 and 106 respectively but may be to any
desired control points of the plurality. Moreover, the programme
override circuit POC of FIG. 9 may be employed in association with
devices other than that described. For instance, in association
with switching devices having more than eight states and hence more
than eight control points and associated combinations of switching
functions.
* * * * *