U.S. patent number 3,793,507 [Application Number 05/060,953] was granted by the patent office on 1974-02-19 for integrated parameter display.
This patent grant is currently assigned to Martin-Marietta Corporation. Invention is credited to Robert B. Blizard, Christ W. Pederson, John T. Polhemus.
United States Patent |
3,793,507 |
Blizard , et al. |
February 19, 1974 |
INTEGRATED PARAMETER DISPLAY
Abstract
The integrated parameter display operates with a programmer and
multiplexer to display an unlimited number of meters. The meter
faces are provided on a film strip which are selectively projected
onto a screen. The meter reading is superimposed on the selected
meter face by a galvanometer in accordance with the value of a
parameter being measured. The meter faces are placed on a film
strip with a coded address adjacent thereto. The desired address is
punched into a keyboard and compared with the film strip being
driven until the selected address matches the address adjacent the
meter face to be displayed.
Inventors: |
Blizard; Robert B. (Littleton,
CO), Pederson; Christ W. (Littleton, CO), Polhemus; John
T. (Englewood, CO) |
Assignee: |
Martin-Marietta Corporation
(New York, NY)
|
Family
ID: |
26740556 |
Appl.
No.: |
05/060,953 |
Filed: |
August 4, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
524911 |
Feb 3, 1966 |
3548378 |
Dec 15, 1970 |
|
|
Current U.S.
Class: |
353/26A; 250/555;
353/26R |
Current CPC
Class: |
G01C
23/00 (20130101) |
Current International
Class: |
G01C
23/00 (20060101); B64D 45/00 (20060101); G06k
007/015 () |
Field of
Search: |
;235/61.12R,61.12N,92V,61.7 ;250/219D,219DC ;353/26 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wilbur; Maynard R.
Assistant Examiner: Gnuse; Robert F.
Attorney, Agent or Firm: Sughrue, Rothwell, Mion, Zinn and
Macpeak
Parent Case Text
This application is a division of Ser. No. 524,911 filed 2/3/66 now
U.S. Pat. No. 3,548,378.
Claims
What is claimed is:
1. A film strip for use with an integrated parameter display
including a viewing screen adapted to display said film strip
including:
a plurality of different graphic illustrations on said film strip
adapted to be displayed individually on said screen;
a coded strip adjacent said graphic illustrations including a
plurality of differentiable indicia representing different binary
addresses for each graphic illustration, adapted to be read by
sensing means in said integrated parameter display which causes a
selected graphic illustration to be nominally positioned before the
viewing screen; and
alternating differentiable centering indicia, one said indicia
being shorter than the other indicia so that said graphic
illustration is centered with respect to the viewing screen when a
pair of spaced centering sensing means are positioned within said
one of said indicia.
2. A film strip, as set forth in claim 1, wherein said graphic
illustrations are placed at right angles to the length of the film
strip.
3. A film strip as set forth in claim 1 further including
differentiable read command indicia for causing said parameter
display to read the indicia representing a binary address when said
address indicia is properly aligned with address indicia sensing
means.
4. A film strip as set forth in claim 3 wherein said differentiable
indicia representing binary addresses and centering and read
command information comprise a plurality of areas each of said
areas having either a first or second light transmissible
characteristic.
5. A film strip as set forth in claim 4 wherein the shorter of said
centering indicia corresponds to areas having the first
transmissible characteristic while the remaining centering indicia
comprises areas having the second transmissibility characteristic,
said differentiable centering indicia being positioned serially
along the length of the film, said areas having the first
transmissibility characteristic being positioned completely within
boundaries defined as the colinear extension of the boundaries of
said graphic illustrations transverse to the length of the film,
each of said centering indicia areas having the second
transmissibility characteristic overlapping a defined boundary.
6. A film strip as set forth in claim 5 wherein the address
representing indicia associated with each graphic illustration is
completely contained within the defined boundaries associated with
said graphic illustration.
7. A film strip as set forth in claim 6 wherein said differentiable
read command indicia are positioned serially along the length of
the film, a read command indicia area having the first
transmissibility characteristic being associated with each graphic
illustration and being contained within said defined boundaries
associated with said graphic illustration, read command indicia
areas having the second light transmissibility characteristic being
located alternately with respect to the read command indicia areas
having first transmissibility characteristics and overlapping a
defined boundary.
8. A film strip as set forth in claim 1 wherein said graphic
illustrations are meter faces.
9. In a data record positioning system for use in a data record
display system including a viewing screen, said data record being
in the form of a movable film strip containing a plurality of
graphic illustrations, a coded strip adjacent each graphic
illustration including a plurality of differentiable indicia
representing a different binary address for each graphic
illustration, said positioning system including control means
responsive to the address indicia and a comparison address code in
an address selector register for moving the film strip to a
predetermined position whereby a selected graphic illustration is
nominally before the viewing screen, wherein the improvement
comprises:
alternating differentiable centering indicia associated with each
graphic illustration, and
first and second spaced centering sensing means, operable in
response to said centering indicia,
said control means including means responsive to said centering
sensing means for centering a graphic illustration with respect to
the viewing screen after the film strip has moved to a
predetermined position.
10. The positioning system of claim 9 wherein said control means
includes means for producing a signal indicating that the film
strip is at the predetermined position, said centering means
includes bistable circuit means, enabled by said signal, for
generating first or second direction signals in response to the
state of said centering sensing means, and means responsive to said
direction signals for moving said film strip in a first or second
direction whereby the film strip is centered.
11. The positioning system of claim 10 wherein said differentiable
indicia representing centering information comprises areas of first
and second light transmissibility characteristics, said centering
sensing means comprises photosensitive elements, centering of a
graphic illustration being effected when the first and second
photoresponsive elements simultaneously receive light from the area
having the first transmissibility characteristic of the centering
indicia associated with the graphic illustration.
12. The positioning system of claim 11 wherein said film strip
further includes differentiable read command indicia associated
with each graphic illustration for causing said control means to
read the indicia representing a binary address, and further
including comparator means for comparing said read address code
indicia and said comparison code and for generating said signal
indicating that the film strip is at the predetermined location
when said read address code and comparison code correspond.
13. The positioning system of claim 9 wherein said control means
further includes means, responsive to the address indicia and the
comparison code when there is a lack of correspondence
therebetween, for causing said film to move in the direction of the
graphic illustration corresponding to said comparison address.
14. The positioning system of claim 13 wherein said means for
causing film movement in the direction of the comparison address
includes logic means, responsive to the most significant digit of
the address indicia and comparison address at which
non-correspondence exists, for producing direction signals, said
control circuit further including motor direction control circuitry
responsive to said direction signals.
15. The positioning system of claim 14 whrein said control circuit
includes means for indicating when an invalid address is supplied
to said address selector register, said invalid address means
comprising counter means for producing a motor disable signal in
response to receiving a predetermined number of said direction
signals and lamp means, responsive to the disable signal for
indicating to the operator that an invalid address has been
supplied to the address selector register.
16. The positioning system of claim 9 wherein said film includes
analog to digital switching indicia, said control means further
including means responsive to the switching indicia for switching
the system to a discrete reading mode of operation.
Description
This invention relates to a multiple meter display or integrated
parameter display. More particularly, the invention relates to a
device for displaying any one of a plurality of meter faces upon a
viewing screen.
As the aerospace technology becomes more sophisticated, it is
necessary for the pilot of an aircraft or spacecraft to be provided
with an ever increasing number of meter readings so that he can
properly monitor the various functions of his vehicle. However,
because of size and weight limitations, the number of meters that
can be included in such an aircraft or spaceship is limited. Also,
the cost of such a large number of meters may be prohibitive. With
respect to ground equipment used in support of aircraft and
spacecraft, the number of meters needed may be even greater than in
the aircraft or spacecraft itself since it may be desirable to
monitor many additional functions of the craft which are not
essential for the pilot's operation thereof, but are nevertheless
of significance. Again, such a large number of meters become almost
prohibitive both from a space standpoint and from a cost
standpoint. Thus, it can be seen that because of limitations of
space, weight and cost, a new arrangement for meter display is
clearly needed.
Among the objects of this invention are to provide a multiple meter
or integrated parameter display; to provide such a display in which
virtually an unlimited number of meters may be displayed as
required; to provide such a display in which the meter faces are
placed on a film strip for projection onto a screen; to provide
such a display in which any one of the meter faces may be displayed
on the screen rapidly; to provide such a display which may be
connected to a conventional programmer and multiplexer for sampling
data; to provide such a display in which a data stream address is
compared with the address on the screen of the display, and when
they match, the data from the multiplexer is utilized to control a
galvanometer which indicates on the screen the value of the data
being monitored; to provide such a display in which the
galvanometer is a mirror galvanometer which projects a light beam
on the screen to give a visual indication of the value of the data
being monitored; to provide such a display in which the meter face
displayed is chosen by punching an address into a keyboard address
selector and register; to provide such a display in which the
address for each meter face is placed on the film strip next to
each meter face; to provide such a display in which the selected
address is compared with the address for the meter face being
displayed; to provide such a display in which film drive means is
provided to cause a meter face to be displayed whose address
matches the selected address; to provide such a meter display in
which the address is placed on the film strip next to the meter
face; to provide such a display in which rapid updating of each
meter reading may be provided; to provide such a meter in which the
updating interval may vary for each meter; to provide such a
display in which additional meter faces may be added or removed
from the film strip; to provide such a meter display in which
either analog or discrete readings may be provided; and to provide
such a meter display which is fast and efficient in operation.
Additional objects and novel features will become apparent from the
description which follows, taken in conjunction with the
accompanying drawings, in which:
FIG. 1, is a diagrammatic illustration of the elements which make
up the integrated parameter display of this invention showing their
inter-relationship with each other and with a conventional data
monitoring system;
FIG. 2, is a front elevation of the integrated parameter display of
this invention;
FIG. 3, is an offset horizontal section taken along line 2--2 of
FIG. 1 to show some of the internal details of the integrated
parameter display;
FIG. 4, is a fragmentary front elevation on an enlarged scale,
showing an alternative meter face for discrete readings;
FIG. 5, is a circuit diagram of a keyboard address selector and
register utilized in this invention;
FIG. 6, is an enlarged fragmentary elevation of a portion of film
strip showing the address markings thereon and the manner in which
they cooperate with the photo diodes to produce a signal indicative
of the film position;
FIG. 7, is a circuit diagram of the film read register utilized in
conjunction with this invention;
FIG. 8, is a partial circuit diagram of the keyboard address
comparator used in conjunction with this invention;
FIG. 9, is a truth table for explaining the operation of the
circuit of FIG. 8; and
FIG. 10, is a circuit diagram of the various motor control
circuits.
In accordance with this invention, it is contemplated that the
multimeter display system which may also be referred to as
integrated parameter display system may be utilized with either
airborne or ground equipment for aircraft, missiles and spacecraft
for providing a substantially instantaneous reading of any one of
many thousands of parameters being studied. As seen in FIG. 1, the
conventional data gathering system comprises a programmer which
sends signals into a multiplexer indicating which of the many
sensors connected to the multiplexer is desired to be read at a
particular time. The multiplexer then sends a signal from the
particular sensor to be read to a computer which in turn transfers
the information to a control processor. This information is stored
in the control processor to be studied at a later date, as
required. Although only one multiplexer is shown, it will be
understood that the programmer may be connected to many
multiplexers which in turn receive signals from many sensors, the
total number of sensors in a particular system may be many
thousands. However, it can be seen that where an instantaneous
reading of a particular parameter is desired, it would be necessary
to provide a separate meter for each reading which is to be
observed. Obviously, where several thousands parameters are being
measured, it is physically impossible to provide a separate meter
so that each of these parameters can be instantaneously observed.
Also, it will be very difficult for a person to observe such a
large number of meters even if this number could be provided. The
problems are compounded with respect to airborne equipment because
the size, weight and expense of the equipment involved becomes
prohibitive.
With the integrated parameter display D of this invention, the
faces of the many thousands of meters to be read are placed on a
film strip which can display any one of the faces on a screen
within a short time period, such as two seconds or less. The data
which provides the reading for the meter is periodically updated,
as discussed below. As can be seen from FIG. 1, the data stream
address is fed into a digital address comparator directly from the
programmer and the data pulses from the multiplexer are fed into a
sample and hold circuit. The operator of the integrated parameter
display punches an address such as a 4 digit octal number into a
keyboard address selector and register which in turn feeds this
information into a keyboard address comparator. The comparator
compares the address fed into it with the address on the film
adjacent the meter face being displayed on the screen as supplied
by the film read register. If these two addresses do not match, the
film drive is activated to drive the film to a position such that
the correct meter face is projected onto the screen. A signal
indicative of the particular meter face being displayed on the
screen is transmitted by the film read register to the digital
address comparator which in turn feeds the correct information from
the data stream address for that particular meter displayed on the
screen to the sample and hold circuit. The sample and hold circuit
then reads the data from the data pulses supplied to it by the
multiplexer which correspond with the meter face being displayed
and this information in analog form is fed to a mirror galvanometer
which projects a light bar onto the image of the meter face on the
screen to give a meter reading.
The multiplexer or other data source could supply digital data
information in addition to or instead of analog data pulses. In
this case, a digital to analog converter would be utilized in
addition to or instead of the sample and hold circuit, as shown in
dotted lines in FIG. 1.
As seen in FIG. 2 and 3, the integrated parameter display D may be
mounted in a housing having sidewalls 10 and 11, top and bottom
walls 12 and 13 and a rear wall 14. A front wall 15 has a viewing
screen 16 mounted therein provided with a row of are used lights 17
above and below the screen. These lights are used when a discrete
reading is desired as will be more fully described below in
connection with FIG. 4. It will be understood that the lights 17
can be arranged in vertical rows along the sides of screen 16
rather than in horizontal rows across top and bottom, as desired.
The number of lights may be varied as described below, eight lights
being shown for illustrative purposes only.
Conveniently, a film strip 18 is mounted on a pair of spools 19 and
20 which are mounted on spindles 21 and 22 attached to a diagonal
wall 23 which extends between front wall 15 and a front edge 24.
The film 18 is fed through a film guide 25 mounted between the
spools and directly behind a lens 26 but in front of a light 27
mounted in a housing 28 on diagonal wall 23. The particular meter
to be read is selected by punching a 4 digit address into a
keyboard 29 which is connected to the address register by suitable
wiring 30. Of course, it will be understood that the keyboard may
be mounted directly in the case for display D, if desired. In a
manner to be described, this action energizes motor 31 of FIG. 3
which, through a pulley 32, causes drive mechanism 33 mounted on
bracket 34 to drive the film in one direction or the other until
the proper meter face image is positioned between the light and the
lens. In order to provide adequate cooling for the housing a fan 35
is attached to motor 31.
The film image is projected through an opening 36 in front wall 15
to the right of screen 16. The image is reflected off a mirror 37
mounted on rear wall 14 onto screen 16. It will be noted that a
portion of the image does not strike the screen but is directed
against a photo diode array comprising a plurality of photo diodes
38 mounted in a housing 39. In addition to the meter face image, a
coded address in is placed on the film next to the face, as
discussed more fully below in connection with FIG. 6. Thus, certain
of the photo diodes will be activated in response to the light
transmitted through the address portion of the film so that a
comparison may be made between the address of the meter face being
displayed with the address which has been punched into the keyboard
29. When the film address matches the address punched on the
keyboard, the motor will be deenergized so that the image of the
desired meter face will be projected on screen 16 for viewing.
Conveniently, the digital address 40 may be placed on the meter
face as shown in FIG. 2, so that the operator may verify that he
punched the correct address into the keyboard.
In addition, a second light source 41 is provided within a box 42
which is mounted in the case to the left of opening 36 and focused
througe a slit 43 onto the mirror galvanometer 44. The mirror
galvanometer pivots about a pivot 45 in response to a signal
representing the particular value of the parameter being measured
as supplied by the multiplexer of FIG. 1. Thus, the light beam 46
from box 42 is reflected by the mirror galvanometer 44 onto screen
16, as shown in FIG. 3 to provide a light bar 47 as shown in FIG. 2
to indicate the meter reading.
For some indications, a discrete reading is more useful than an
analog reading. For example, sometimes it is only necessary to know
whether a particular valve is open or closed, a particular switch
on or off, etc. In that case, the film strip may carry an image of
the type shown in FIG. 4 in which eight conditions may be read by
observing lights 17. The number of discrete readings which may be
placed on one meter face is limited only by the number of bits in
each data word from the data stream. A meter face for an 8 bit data
word has been shown for illustrative purposes.
The keyboard address selector and register shown in FIG. 1 and
partially represented by keyboard 29 in FIG. 2 may be more fully
understood by reference to FIG. 5. The keyboard address selector
converts a 4 digit octal address to a 12 bit binary address and
stores this address in a 12 bit register. The eight switches
numbered 0 to 7 on the keyboard are connected to three OR gates 48,
49 and 50 which in turn are connected to three single-shot-circuits
51, 52 and 53 respectively. Thus, when a key is depressed, the
digit is converted to a 3 bit binary word and this word is
direct-set into a 3 bit register. The wave pulses generated by the
single-shot-circuits 51, 52 and 53 are schematically shown thereon.
In addition, three shift pulses are also generated each time a
number on the keyboard is depressed to shift the 3 bit binary word
into the 12 bit storage register. Thus, a signal is transmitted
through OR gate 54 to single-shot-circuit 55 which sends a signal,
having the wave form shown, to OR gate 56 and to
single-shot-circuit 57. The second pulse is generated by a
single-shot-circuit 57 which pulse is sent to OR gate 56 and
single-shot-circuit 58. Finally, single-shot-circuit 58 generates a
pulse which is fed into OR gate 56. The three pulses which are fed
into OR gate 58 result in three short pulses being generated by
single-shot-circuit 59, as shown, resulting in a three digit shift
of the 3 bit binary word from the 3 bit register into the 12 bit
register. It will be noted from FIG. 5, that the pulse of
single-shot-circuit 55 is longer than any of the pulses from
single-shot-circuits 51, 52 and 53 so that no shift pulses will be
generated by single-shot-circuit 59 until the 3 bit binary word has
been set in the 3 bit register. The end of the pulse from
single-shot-circuit 55 initiates the shorter pulses of
single-shot-circuits 59 and 57. Similarly, the end of the pulse
from single-shot-circuit 57 initiates the pulses of
single-shot-circuits 59 and 58. The end of the pulse of
single-shot-circuit 58 initiates the final pulse of
single-shot-circuit 59 to complete the shift from the 3 bit
register to the 12 bit register. The pulse from single-shot-circuit
55 is fed through line 60 to the motor stop control circuit for a
purpose to be described in conjunction with FIG. 10.
It can be seen that it will take 4 octal numbers to fill the 12 bit
binary storage register. Thus, by depressing additional keys
sequentially, the additional numbers may be fed into the register.
Such an arrangement provides for selection of up to 2,048 different
addresses with 11 bits allowing the 12 bit to be used for the
selection of a discrete address. Alternatively, the 12 bit may be
used for an analog address so that a selection of up to 4,096
different addresses may be made. In this case, any of the meter
faces may be used for a plurality of discrete readings, with the
discrete lights 17 being switched on by a 13th bit placed on the
film address for that meter face which will switch in a circuit
controlled by a 13 photo diode 39 within housing 40. Of course, the
galvanometer circuit would be switched out at the same time. The
discrete readings can be provided only when the multiplexer or
other data source provides digital information to a digital to
analog converter, as shown in the dotted line portion of FIG. 1, in
order to provide 8 discrete inputs. This operation will be more
clearly understood from the description of FIG. 6 below. If more
than 4,096 addresses are needed, it will be necessary to go to a 5
bit octal address and to use a larger shift register. Of course,
all addresses need not be used. The number of meter faces and
addresses may be increased by splicing them into the film strip or
decreased by cutting them out of the film strip.
As shown in FIG. 6, each meter face on the film normally has
associated with The light a 12 bit binary code or address 61 plus a
relatively short strobe or read bar 62 for determining when the 12
bit binary code should be read and a centering bar 63 for centering
the meter face on the screen. Each light bar represents a binary 1
and each black bar represents a binary 0. The small dotted circles
under the address represent the position of the photo diodes 38
with respect to the image projected upon screen 16. If desired,
address 61 could be provided with a 13th bit for discrete readings
as discussed above. Also, strobe diode 64 and centering diodes 65
are located as shown relative to the projected image. The strobe
bar 62 is made somewhat narrower than the bars of code 61 so that
the addresses will not be read while the film strip is between
positions. The light portion of centering bar 63 is shorter than
the dark portion so that it is not possible for the two centering
diodes 65 to straddle a dark portion indicating that the film is
centered when it is not.
From the film read circuit of FIG. 7, it can be seen that strobe
diode 64, through amplifiers 66 and 67, will enable the AND address
gates, such as AND gates 68 and 69, to allow the address reading
from the address diodes 38 to be transferred via amplifier 70 and
AND gates 68 and 69 into the address register as represented by AND
gates 71 and 72. However, when a different address is punched into
the keyboard 29, as the film 18 begins to move toward the new
address the strobe diode 64 will be deactivated before the address
photo diodes 38 thereby disabling the address AND gates 68 and 69
so that the last address is held in the register represented by AND
gates 71 and 72 until strobe diode 64 is activated by a new
address. Thus, when the light hits the strobe diode 64, it becomes
a low resistance and supplies current to a high gain amplifier 67.
The signal is inverted by amplifier 67 and provides binary 1 or
high signal to the AND gates 68 and 69 as well as other AND gates
which are associated with the other photo diodes (not shown). When
the input to these AND gates from the strobe diode 38 is a binary 1
the cross coupled AND gate flip-flop register 71, 72 is set. On the
other hand, if a binary 0 or low signal is received from photo
diode 38, the register will not be set. In this manner, it can be
seen that the register for each of the photo diodes 38 will be set
or not set, depending on whether binary 0 or a binary 1 is seen by
the photo diodes 38 as they read the address 61 on film strip 18.
However, when another address has been punched in the keyboard 29
causing the film strip to move to another meter face, a dark strip
will move across the strobe diode 64 so that it sees a binary 0,
and the reading in register 71, 72 will remain there until another
binary 1 is seen by the strobe diode. Of course, the information
stored in the film read register of FIG. 1 will then be transferred
to the keyboard address comparator of FIG. 8, as indicated in FIG.
1.
The keyboard address comparator of FIG. 8 compares the address in
the keyboard register of FIG. 1 to the address in the film register
and provides the signal inputs to the motor control circuit of FIG.
10 to drive the motor, and hence the film, in one direction or the
other. From FIG. 8, it can be seen that each stage of the keyboard
address comparator consists of two AND gates such as AND gates 73
and 74. The input from the keyboard register is represented as Q
and Q and the input from the film read register is represented as F
and F. The AND gates 73 and 74 are connected to an inhibit gate,
such as OR gate 75 and inverter 76, as shown. Thus, the comparison
is made of the most significant bit first and if Q does not equal F
then the remaining comparators are inhibited. Referring to the
truth table of FIG. 9, it can be seen that if Q and F are each a
binary 1 then the output signal from AND gate 73 is low, a low
input is provided to OR gate 77 which is connected through line 78
to the motor control circuit 79 of FIG. 10 to drive the motor 31
and the film 18 in one direction. On the other hand, if F and Q are
each a binary 1, then the output of AND gate 74 is low providing a
low input to OR gate 80, connected by line 81 to motor control
circuit 79 causing the motor and film to be driven in the other
direction. Also, if the output from either AND gate 73 or AND gate
74 is low, then the output from inverter 76 will be low which will
inhibit AND gates 82 and 83 of the next comparator section. This
comparator section includes an OR gate 84 and an inverter 85, as
shown,and works the same as the previous section, sending a signal
to the next comparator section only when the output from inverter
85 is high. The purpose of this arrangement is so that OR gates 77
and 80 do not get a signal to move in one direction from one bit
comparison and a signal to move in the opposite direction from
another bit comparison, simultaneously.
When the two inputs F and Q are the same, i.e., either a binary 0
or a binary 1, the output of AND gates 73 and 74 will both be high
so that no signal is sent to OR gates 77 or 80 to initiate the
motor drive. Also, the next comparator stage will be enabled
through AND gate 75 and inverter 76 and a comparison as described
above will be made. This process will continue down the line
through each bit comparison until all bits have been compared. When
the last bit is compared the centering control gates are enabled
and the left-right signals are furnished by the centering photo
diodes 65 until both diodes are in centering bar 63 of FIG. 6.
Photo diodes 65 provide signals through inverters 86 and 87 to
flip-flop circuit comprising AND gates 88 and 89 as shown. The
output from AND gates 88 and 89 is supplied to OR gates 77 and 80
to control the movement of the motor during centering and to OR
gate 90 which is connected by line 91 the motor control circuit 79
of FIG. 10 as shown, to control the motor speed by conventional
means (not shown) which are part of the motor control circuit
79.
The various motor control circuits are clearly shown in FIG. 10
which are provided here for stopping the motor when a wrong address
is punched into the keyboard or the end of the film is reached and
for starting the motor when the select switch is closed, as well as
means to prevent the motor from running until the complete address
has been punched into keyboard 29.
If an invalid address is punched into the keyboard, i.e., an
address which is between two valid addresses, in a situation where
all possible addresses are not in use, the motor drive circuit
would continue reversing back and forth between the two valid
addresses trying to find the one that is missing. To prevent this
continued reversal, the reversing signal is fed through an OR gate
92 into a 3 bit counter comprising flip-flops 93, 94 and 95 which
are interconnected, as shown, and are connected to the motor
control circuit 79. The number of reversals necessary to stop the
motor is arbitrary. However, in the circuit shown, when seven
reversals have been made, the flip-flop circuits all contain a
binary 1 which satisfy the three input AND gate 96 clearing the
motor start flip-flop which includes two AND gates 97 and 98
thereby stopping the motor by breaking the circuit between the
select switch and motor control circuit 79. Also, the output of AND
gate 96 is connected through a flip-flop, which includes AND gates
99 and 100, and AND gate 101 to OR gate 102, which is connected to
the base of transistor 103 and completes the circuit to a
no-valid-address light 104 which is turned on so that the operator
realizes that he has punched an incorrect address. The other input
to AND gate 101 is supplied through line 91 from the centering
circuit.
To prevent the film from running off the spools 19 and 20 at either
end, a section of film is provided at one end with an address in
which each of the 12 bits is a binary 1 and the other end is
provided with an address in which each of the 12 bits is a binary
0. A group of these addresses are put on each end of the film and
read by two AND gates. For example, AND gate 105 may be provided
for the binary 1 end of the film and AND gate 106 may be provided
for the binary 0 end of the film. Each gate is provided with 12
inputs, one for each bit on the film address. If the film drive is
driven beyond the normal addresses, one of these gates will be
satisfied, clearing flip-flop 97, 98 to stop the motor. It will be
noted that both AND gates 105 and 106 are also connected into OR
gate 102 so that the no-valid-address light 105 will be lit up.
In addition, it is desirable to prevent the motor from running
while an address is being punched into the keyboard 29. To prevent
this, the flip-flop circuit 97, 98 is cleared by the first pulse
through line 60 from the shift OR gate 54 of FIG. 5. This disables
the motor drive circuit. After the complete address has been
punched in, the select key is depressed to reset flip-flop 97, 98
and allow the motor to run so that the correct address may be found
and the proper meter face displayed on screen 16.
For high operation speed, the motor may be driven at different
speeds in order to reach the desired address in the minimum amount
of time. The circuitry for this is not illustrated, but it will be
understood that after the desired address is shifted into the
keyboard 29 and the select switch is closed, the motor will always
start at high speed, driving the film toward the correct address.
Since the motor is running in high speed, the film will overshoot
the correct address and the first address after the correct address
will result in a reverse signal to the motor control cricuit 79. At
the same time, a flip-flop within circuit 79 is cleared, causing
the motor to go to medium speed in reverse. The film is now driven
at medium speed back to the correct address and then at slow speed
until the meter face is centered by centering diodes 65. However,
small errors in centering will not affect the accuracy of the
readings since the scale is placed at right angles to the length of
the film strip, as shown in FIG. 6. Thus, the accuracy of
positioning of the scale on the screen is dependent on the machine
tolerances of film guide 25 and the accuracy of placement of the
meter scales on the film strip.
After the film has been centered on the desired meter face, the
address on the film is compared with the data stream address of the
programmer by means of the digital address comparator of FIG. 1.
If, at the time a transfer pulse is initiated from the programmer
to the sample and hold circuit and all of the address bits coming
in from the data stream address are identical, bit for bit, to the
address in the film read register, as compared by the digital
address comparator, a flip-flop (not shown) will be set in the
sample and hold circuit to allow a data sample from the data pulses
to be read into the sample and hold circuit. When the next transfer
pulse arrives the flip-flop will be cleared, disconnecting the data
pulses from the sample and hold circuit. The previous data sample,
however, will be held in the sample and hold circuit, and updated
as described below, until a different address has been punched into
the keyboard. The bit by bit comparison within the digital address
comparator is made by a set of exclusive OR gates (not shown), one
gate being provided for each bit. The output of all the exclusive
OR gates are fed into an AND gate within the sample and hold
circuit along with the transfer pulse from the programmer. If the
output of all of the exclusive OR gates is high when the transfer
pulse occurs, the flip-flop in the sample and hold circuit will be
set. If any one of the outputs is low, then the addresses do not
match and the flip-flop is not set. The sample and hold circuit
always holds the last reading or data sample it has received and
provides a signal to mirror galvanometer 44 which causes it to
rotate an amount proportional to this data sample to project a
light beam 46 onto screen 16, as described above, giving a reading
for the particular meter face being displayed on the screen.
Advantageously, the meter reading being displayed will be updated
continually until a different address is punched into the keyboard.
Every time the data stream address matches the selected address,
the sample and hold circuit will read and store the data sample
from the data pulses and update the meter reading. The more
critical parameters may be sampled as often as 400 times per
second, for instance, whereas the less critical parameters may be
sampled only two times per second or so. The frequency of sampling
is built into the programmer.
From the foregoing, it can be seen that the novel objects and
features of this invention have been fulfilled to a marked degree.
An integrated parameter display has been provided for operation
with a conventional programmer and multiplexer in which a virtually
unlimited number of meters may be displayed by placing the meter
faces on a film strip for projection onto a screen. The meter
reading is obtained by utilizing a galvanometer for projecting an
image onto a screen to give a visual indication of the value of the
parameter being measured. The meter faces are placed on a film
strip with a coded address adjacent thereto. The desired address is
punched into a keyboard and compared with the film address, the
film strip being driven until the selected address matches the
address adjacent the displayed meter. The film strip can be moved
rapidly to change the meter faces, means being provided to assure
that the wrong meter face is not displayed, whereby the address
number is placed on the meter face so that the operator can tell
whether or not the meter face being displayed is the one he
intended. In addition, means is provided for updating each meter
reading at preselected intervals and this interval may vary for the
particular parameter being monitored. Conveniently, additional
meter faces may be added to the film strip or meter faces may be
taken off the film strip as required. Furthermore, the readings may
be given in either analog or discrete readings.
Although a preferred form of this invention has been illustrated
and described, it will be understood that various changes and
variations may be made, all without departing from the scope of
this invention. For example, in place of the mirror galvanometer, a
galvanometer having a pointer may be used wherein an image of the
pointer is projected onto the meter face image on the screen.
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