U.S. patent number 3,613,064 [Application Number 04/814,537] was granted by the patent office on 1971-10-12 for alarm control.
This patent grant is currently assigned to Defensive Instruments, Inc.. Invention is credited to Curtiss C. Krueger, Charles H. Peterson.
United States Patent |
3,613,064 |
Peterson , et al. |
October 12, 1971 |
ALARM CONTROL
Abstract
An alarm control system has an internal receiver module and an
internal ultrasonic intruder detector module connected to one input
channel of a bistable flip-flop. An internal heat sensor fire
detector is connected to another input channel. Remote inputs are
connectable to either input channel. Inputs in the first channel
cause the flip-flop to change to the alarm state and to operate a
relay driver which partially completes AC outlet relays and remote
output relays and which starts an adjustable delay timer to operate
a second relay driver for partially completing a horn relay and for
partially completing a circuit to a reset delay device. A function
selector selectively grounds one or more of the output relays
preparatory to operation of the flip-flop and relay drivers so that
the circuits are ready to operate the appropriate output when the
flip-flop is biased into an alarm state. The second channel is
connected directly to the second relay driver and to the function
selector for overriding the function selector for grounding all
relay coils so that all signals operate when an extremely hazardous
condition such as fire is sensed by second channel sensors.
Inventors: |
Peterson; Charles H. (San
Diego, CA), Krueger; Curtiss C. (San Diego, CA) |
Assignee: |
Defensive Instruments, Inc.
(Pittsburgh, PA)
|
Family
ID: |
25215350 |
Appl.
No.: |
04/814,537 |
Filed: |
April 9, 1969 |
Current U.S.
Class: |
340/527; 340/552;
367/93; 340/384.1; 340/326; 340/565 |
Current CPC
Class: |
G08B
19/00 (20130101) |
Current International
Class: |
G08B
19/00 (20060101); G08b 007/00 (); G08b
013/00 () |
Field of
Search: |
;340/258,213,412,420,220,326,371,213.1 ;317/137 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Caldwell; John W.
Assistant Examiner: Palan; Perry
Claims
That which is claimed is:
1. Alarm control apparatus comprising:
energy sensing input means,
control circuit means connected to the energy sensing input
means,
power source connected to the control circuit means,
more than one signalling means connected to the control circuit
means,
function selector means connected to each signalling means
separately from the control circuit means for individually and
collectively enabling the signalling means for response to the
energy sensing means and control means.
2. The alarm control apparatus of claim 1 wherein the energy
sensing input means comprises first and second energy sensing input
means, and wherein the second energy sensing input means is
connected to the signalling means, whereby the signalling means
operates in response to the control circuit means in response to
energy sensing by the first input means, and whereby the signalling
means directly operate in response to energy sensing by the second
input means.
3. The alarm control apparatus of claim 2 wherein the energy
sensing input means comprises first and second energy sensing input
means, and wherein the second input means is connected to the
function selector means for selectively enabling the signalling
means in response to energy sensing by the second input means.
4. The alarm control apparatus of claim 3 wherein the first energy
sensing input means comprises an ultrasonic intruder detector means
and wherein the second energy sensing input means comprises heat
sensor means.
5. The alarm control apparatus of claim 4 wherein the first energy
sensing means additionally comprises a radiofrequency receiver and
connection means for remote accessories, and wherein the second
input means further comprises second connections for remote
accessories.
6. The alarm control apparatus of claim 1 wherein the control
circuit comprises a bistable flip-flop circuit connected to the
energy sensing input means.
7. The alarm control apparatus of claim 6 wherein the control
circuit means further comprises relay driver means connected to the
flip-flop means and signal relay means connected to the relay
driver means for controlling the signalling means.
8. The alarm control apparatus of claim 7 wherein the control
circuit means further comprises adjustable delayed timer means
interposed between the flip-flop circuit and the relay driver
means, a reset switch means connected to the flip-flop means and
reset delay means connected between the relay driver means and the
reset switch means for delaying resetting of flip-flop to a no
alarm condition.
9. The apparatus of claim 1 wherein the control circuit means
include time delay apparatus comprising a first normally on
transistor having an emitter connected to ground, a diode connected
to a collector of the first transistor, a capacitor connected
between the diode and ground, a first resistor connected between
the capacitor and a source of DC power whereby the capacitor is
charged through the first resistor when the first transistor is
off, a second transistor having a base connected to the capacitor
and having an emitter-collector circuit connected to a source of
power and to an alarm response circuit for operating the alarm
response circuit when the second transistor is conductive, an
emitter of the second transistor being connected through second
resistor to a source of power and through a potentiometer to ground
whereby the emitter is held at a voltage higher than the base when
the capacitor is grounded through the first transistor, and whereby
adjusting the potentiometer controls the time required after the
first transistor has been turned off for the capacitor to charge
sufficiently to turn the second transistor on thereby completing
circuit means between the power source and a signalling means.
10. The apparatus of claim 1 wherein the function selector means
includes a function selector switch for selectively connecting a
single movable pole to first, second and third connecting lines
which are connected to respective signalling means contacts
comprising: a movable pole, a first contact connected to a first
line, a second contact connected to the second line and connected
via a unidirectional element to the first line, a third contact
connected to the third line, and a fourth contact connected to the
third contact via a unidirectional element and connected to the
second contact via a unidirectional element, whereby the first
contact provides a pole contact for the first line, the second
contact provides a pole contact for first and second lines, the
third contact provides ground contact for the third line and the
fourth contact provides pole contact for first, second and third
lines.
11. The apparatus of claim 1 wherein the control circuit means
includes a reset time delay comprising a unijunction transistor
connected to a source of power and to an alarm reset switch which
is in turn connected to a flip-flop circuit, a unijunction
transistor having a biasing connection connected to a capacitor
which is grounded on one side thereof and which is connected
through a resistance to the output of a time delay relay, whereby
closing the alarm reset switch after the time delay relay has
become energized charges the capacitor through the resistance to a
potential required to make the unijunction transistor conductive
enabling resetting of the control circuit means after a time
delay.
12. An alarm control system comprising
first and second energy sensing input means,
control circuit means connected to the energy sensing input
means,
signalling means connected to the control circuit means and to the
second energy sensing means for controlled response to the energy
sensing of the first input means and for direct response to energy
sensing by the second input means,
function selector means connected to the signalling means
separately from the control circuit means for severally enabling
the signalling means for response to the sensing means and control
means, and
power source means connected to the control circuit means and to
the signalling means.
13. The alarm control system of claim 12 wherein the second energy
sensing input means is connected to the function selector means for
overriding the function selector means and enabling all signalling
means for response to energy sensing in the second input means.
14. The alarm control system of claim 13 wherein the control
circuit means comprises a bistable flip-flop connected to the first
and second energy sensing input means,
an adjustable delay timer connected to the bistable flip-flop,
first and second relay drivers respectively connected to the
flip-flop and to the adjustable delay timer,
an AC outlet relay and a remote output relay connected to the first
relay driver,
a horn relay connected to the second relay driver,
a reset delay and reset switch connected between the second relay
driver and the flip-flop for resetting the flip-flop after a time
delay,
and wherein the function selector is connected to the AC outlet
relay, to the remote output relay, and to the horn relay, whereby
the function selector may select either AC outlet control, AC
outlet control and horn operation, AC outlet control, horn
operation and remote output, or remote output,
and wherein the second energy sensing input means is connected to
the flip-flop, to the second relay driver and to the function
selector for overriding the function selector and operating all of
the signalling means in response to the energy sensing by the
second input means.
15. A self-contained alarm system for sensing the presence of
intruders or of excessive heat and for responding by a
self-contained alarm device, comprising a power source having a
cord and plug for connection to a conventional 110-volt AC input
source and having transformer and rectifier means for producing a
relatively low DC voltage from the AC input voltage, multiple
signal means connected to the power source, an ultrasonic intruder
sensor connected to the power source, a fire sensor having a heat
sensitive switch connected to the power source, a radiofrequency
sensor, an alarm control circuit connected to the fire sensor, to
the ultrasonic intruder sensor and to the radiofrequency sensor and
to the signal means and function selector means connected to the
signalling means independently of the control circuit, for
operating a signal means in response to an input from the
sensors.
16. The method of controlling alarms comprising connecting
condition sensors to two input channels, connecting the input
channels to a bistable flip-flop circuit, changing state of the
bistable flip-flop in response to condition sensing by one of the
sensors, connecting a power source to a first set of relay coils in
response to changing of state of the flip-flop, beginning operation
of a time delay circuit in response to changing of state of the
flip-flop, connecting the power source to a relay for operating the
local signal in response to completion of the time delay circuit
and selectively grounding any or all of the relays preparatory to
the changing of state of the flip-flop device, whereby selected
relays are enabled for causing operation of relay switches in
response to changing of state of the flip-flop device.
17. The method of claim 16 further comprising overriding the time
delay and function selector and actuating all signals when input is
received on a selected one of the input channels.
18. The method of claim 18 wherein the beginning operation of a
time delay circuit comprises the sequential steps of biasing a
first transistor off by providing an emitter potential higher than
a base potential, shorting a capacitor connected to the transistor
base, unshorting the capacitor upon a start signal, slowly charging
the capacitor to a potential above emitter potential, thereby
causing the transistor to turn on completing an alarm circuit and
controlling time delay by varying emitter potential.
Description
BACKGROUND OF THE INVENTION
The need for improved fire and burglar alarms is well recognized.
Heretofore, compact plug-in equipment, which requires no special
installation and which is contained in a single small
self-sufficient package, has been unavailable. Moreover, combined
burglar alarm and fire alarm control equipment which effects a time
delay control for the burglar alarm and immediate response for fire
alarms is not known The present apparatus accepts radio signals,
detects motion and senses heat and controls an alarm response in a
completely effective self-contained system without the use of
accessory equipment. However, accessory alarm sensors or remote
alarm indicating systems can be connected to the present system to
further extend its effectiveness and versatility. The present
system, in response to remote radio transmitters or remote
electrically connected devices, responds with time delayed local
signals and the completing of power connections for remote
signalling devices.
Most systems of conventional design connect relay control circuits
directly to various alarm sensors. Because it is desirable to
provide a latching function so that once the alarm is actuated it
remains actuated until intentionally reset, many of the latching
relays that are commercially available are very complex
mechanically and are highly unreliable.
Timing circuits heretofore available have experienced difficulty in
providing an adjustable range ratio as high as the present circuit
while maintaining a linear time scale on the time delay adjustment
control. Time delay controls such as in the present invention in
which the time delay circuit resets itself instantaneously and can
immediately resume the timing cycle with a very small amount of
error have heretofore been unavailable.
Multiple function selection switches of conventional design require
complex multiple-pole selector switches. The present invention
avoids the use of such devices by an unusual arrangement of diodes
and a single pole switch.
One very real danger in the successful use of intruder alarms,
particularly, is the danger that the intruder will disconnect the
alarm or disable the alarm such as by depressing the reset button
and resetting the equipment to a no alarm condition. The present
apparatus overcomes that possibility by adding a time delay to the
reset equipment so that an alarm output will occur for at least 5
seconds for any trigger caused by any sensor before the equipment
is reset to a no alarm condition.
SUMMARY OF THE INVENTION
The alarm control module receives signals from a multitude of
internal or remotely located sensors and provides logic and timing
functions so that an appropriate alarm indicating device is
actuated. A horn that produces at least 100-db. sound pressure
level is used as an internal alarm indicating device. Two outputs
from the system are used for remotely located alarm indicating
devices. One output is a relay controlled outlet providing 117
volts AC at 600 watts. The second output is a set of normally open
or normally closed dry relay contacts which carry current up to 1
amp.
Various combinations of the alarm module outputs can be selected by
the switching circuitry incorporated in the equipment. The function
selector enables the output or combination of outputs as selected.
When an alarm trigger signal occurs, the outputs that are enabled
will then be actuated; the outputs remain actuated until the system
is reset or until a complete loss of power occurs.
The system has two basic alarm trigger inputs. Triggering input A
causes all logic and timing functions to act normally and causes
the output reaction to be that established by the function
selector. Input B, referred to as the instant alarm input, bypasses
all timing functions and function selection; a trigger at input B
causes all outputs to be actuated instantaneously regardless of
control positions.
Provisions are made in the system to accept three kinds of internal
modules or sensors, which are a heat sensor, an ultrasonic intruder
detector module, and a radiofrequency receiver module. All
low-voltage inputs and outputs of the system are located on
terminal strips mounted on the rear of the modules. 117-Volt AC
60-cycle power or internal rechargeable battery power operates the
system which is always ready irrespective of external power
distribution systems or switches.
The internal ultrasonic intruder detection system is connected to
the first triggering input channel to employ all logic and timing
functions. Preferably a system is used such as described in
copending application "Ultrasonic Detection System," filed Mar. 10,
1969, by C. H. Peterson and C. C. Krueger, is used. An internal
radio receiver is connected to the same triggering input channel as
the ultrasonic intruder detection system. Alternatively, the
receiver may be connected to the immediate response input channel.
When the receiver is keyed by radiofrequency within its
sensitivity, logic and timing functions of the control circuit are
set into operation. One or more radiofrequency transmitters may be
located at convenient locations remote from the alarm control. The
transmitters may be operated by buttons depressed by persons who
wish to set off the alarm control, or the transmitters may be
controlled by remote perimeter metering devices such as black light
photoelectric cells, contact or broken circuit sensitive devices.
The transmitters may be connected to heat or flame sensitive
devices to provide an alarm system with remote wireless fire
detection stations. Transmitters may be used with any automatic
monitoring systems. Personally carried transmitters may be
connected to battery operated health condition monitors.
Each input circuit is provided with external connection jacks
terminals so that any external detector may be wired to the alarm
control and may activate its immediate response total signal mode
or its programmed response mode. Any condition monitor may be
connected to either input. The alarm system may be wired to remote
panic button stations or to any condition monitor.
Very little power is used in standby operation when AC power is
off. The equipment runs for an extended period when the internal
battery power operates the system. When AC power is applied to the
system, the battery is charged. If the AC power supply fails, the
internal battery is automatically switched in and continues to
supply power to all the module circuits except the AC outlet.
One objective of this invention is the provision of alarm control
systems with function selector means for individually and
collectively enabling signaling means to respond to intruders, fire
or other energy producing inputs.
This invention has as another objective the provision of alarm
control systems which have first and second input channels from
sensing means so that sensing means on one channel may operate
through a logic control system to control the operation of
signaling devices and so that energy sensing means on a second
channel may directly operate the signaling devices, bypassing the
logic control circuit.
Another objective of this invention is the provision of alarm
control apparatus with bistable flip-flop circuits for remaining in
an alarm state until intentionally reset.
Another objective of this invention is the provision of alarm
control systems having time delay means for operation of localized
signals in response to circuit tripping and for immediate operation
of remote signals in response to the same tripping and for
selection of local and remote signals.
A further objective of this invention is the provision of time
delay reset means so that alarm control apparatus may not be
deenergized before it has responded to a triggering for a
predetermined time.
These and further objectives of the invention will be apparent from
this disclosure which includes the specification which is the
written material, including the claims, and from the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic block diagram of the interrelationship of
elements of the invention.
FIG. 2 is a schematic diagram of the electrical components of a
preferred embodiment for carrying out the objectives of this
invention.
DETAILED DESCRIPTION OF THE DRAWINGS
A reference to the functional block diagram FIG. 1 will aid in
understanding the following description. Multiple numbers, for
example 10-20 refer to elements having those and intermediate
numbers in FIG. 2. The equipment is comprised of 10 major circuit
sections, which are identified in the drawings as flip-flop 10-20,
AC outlet relay 6A, remote output relay 7A, adjustable delay timer
22-30, horn relay 36A, function selector 50, input A, input B,
reset delay 43-45, and power supply 51-69. The power supply is
connected to all other sections; therefore, for clarity in
understanding the interrelation of other sections, the power supply
connections are not shown in the schematic FIG. 1.
FLIP-FLOP
Every input to the system is first fed to the bistable flip-flop
10-20; the reset command signal is also fed to this stage. This
logic element has two stable states. An alarm trigger signal from
any input causes the flip-flop to set and remain in the alarm state
even though the alarm trigger may be momentary. The flip-flop
remains in the alarmed state until a reset pulse occurs and causes
the flip-flop to assume its original no alarm state. The remainder
of the system therefore, reads out the state of the flip-flop and
acts accordingly. Both outputs of this logic element are used to
drive the circuitry that follows.
AC OUTLET RELAY
117-volt AC power is applied to the AC outlet when the AC outlet
relay contacts close. A transistor switch 9 acts as the relay coil
driver. When the flip-flop 10-20 is in the alarm state, a relay
driver transistor 9 switches on and connects one side of the AC
outlet relay coil 6A to B+. The other side of the relay coil is
connected to the function selector 50. If the function selector has
not been set to enable this relay, an open circuit is presented to
the relay, and, the relay is not energized. If the function
selector has enabled this relay, the relay circuit completes
causing the relay to be energized.
REMOTE OUTPUT RELAY
One side of the remote output relay coil 7A is connected to the
same relay driver transistor 9 as the AC outlet relay 6A. The
remote output relay functions identically to the relay described in
the above paragraph; its coil current is enabled or disabled by the
function selector 50. A form "C" relay contact arrangement 7B (FIG.
2) is used to provide both a normally open and normally closed set
of relay contact outputs.
ADJUSTABLE DELAY TIMER
An adjustable delay timer 22-30 is actuated by the other output of
the flip-flop 10-20. When an alarm state occurs in the flip-flop
the timer circuit begins to time. A variable potentiometer makes
the time delay adjustable from a small fraction of a second to at
least 10 seconds. The output of the timer remains in the no alarm
state until the time period, as set by the control, is reached. At
that time the output of the timer switches to the alarm state. The
delayed alarm signal is fed to the horn relay 36A only; therefore,
the timer is referred to as the Horn Time Delay Control.
HORN RELAY-FLASHER
DC current to the horn is switched on and off by the horn relay
contacts. When an alarm signal output occurs from the adjustable
delay timer, the horn relay 36A is energized. An electronic horn
relay circuit 32-41 associated with the horn relay causes the relay
current to be interrupted at time intervals and durations
established by the electronic circuit. The acoustical output of the
horn, therefore, is not continuous but is a beeping sound. As
before, if the function selector has not been set to enable the
horn relay, no current flows through the horn relay coil, and no
horn output occurs.
FUNCTION SELECTOR
The function selector switch 50 has four positions, which are: AC
outlet only; AC and horn; AC, horn, and remote output; and remote
output only. A diode matrix in conjunction with a single pole
rotary switch are used to enable the combinations of outputs.
INPUT A
Input A of the flip-flop 10-20 is a normally open input. When any
alarm sensor is connected to this input and exhibits a close
circuit, the flip-flop is set in the alarmed state. Even if the
input reverts back to an open circuit condition almost
instantaneously, the flip-flop remains in the alarm state. Because
Input A is a normally open circuit configuration, an infinite
number of alarm sensors can be connected in parallel to this input.
If any one of these alarm sensor circuits close, the alarm trigger
and timing functions commence immediately. Maximum current flow in
this circuit is 2 milliamperes.
INPUT B
Input B, the instant alarm mode input, incorporates a diode matrix
circuit to actuate the flip-flop, horn relay driver, and function
selector simultaneously. The multiple actuation causes the
flip-flop to be set, bypasses the horn time delay circuit, and
enables all relay output functions, regardless of the setting of
the function selector switch.
As long as Input B remains a closed circuit all functions are
actuated instantaneously. If Input Circuit B reverts to an open
circuit at a later time, the output functions that are not selected
or enabled by the function selector switch, are shut off, and only
those functions selected by the selector switch remain in alarm
condition.
RESET
When either Input A or Input B is a closed circuit, it is
impossible to reset the flip-flop. The system, therefore, remains
in the alarmed state until Input A and/or B is cleared.
RESET DELAY
Assuming Input A and B are clear, the system cannot be reset until
5 seconds after the horn relay driver circuit 32-41 has been
actuated. This holds true regardless of the position of the
function selector switch. If the horn is enabled, after the horn
time delay period has passed, the horn sounds and continues
sounding for a period of 5 seconds even though the reset button has
been depressed for the whole duration. It is therefore impossible
to disable the alarm control module from sensing an alarm condition
and from actuating the selected alarm output.
POWER SUPPLY
117-volt AC power is converted to 18-volt DC in the power supply
section 51-69. DC power is supplied to all active sections of
circuitry as well as to the trickle charging circuit for the nickel
cadmium standby battery pack. A solid state switching circuit
automatically connects the battery into the circuit in the event of
AC power loss. In the latter mode of operation there is a 12-volt
nominal B+ voltage. All logic and timing functions operate
identically at either a standby 12-volt voltage or the normal
18-volt voltage. There are two means for identifying on which power
mode the equipment is functioning. A pilot lamp indicates when AC
power is applied to the equipment. A dark pilot light indicates a
loss of AC power or that the AC power switch on the rear of the
module is in the off position. There is also a noticeable
difference in pitch of the audible horn signal, a pure tone
indicating standby battery operation.
The power supply also supplies DC power to the internal RF receiver
module and the internal ultrasonic intruder detector module. Since
the internal heat sensor and the remote accessories connected to
the remote input terminals are all passive devices, they do not
require power. Under no alarm conditions, the power consumption is
very minimal, allowing at least 8 hours of standby power operation.
When the system is in the alarmed condition, the power consumption
is dependent on the number of functions that are enabled. If the
horn is actuated in standby battery mode of operation, 5 to 30
minutes of horn operation is available, depending on the duration
of AC power loss before the horn was actuated. When a standby
battery pack has been completely discharged, 16 hours of AC
operation is required to fully recharge the battery.
DETAILED CIRCUIT DESCRIPTION
In FIG. 2, components utilized for the circuitry herein described
are designated by numbers. Letter designations are used to indicate
connecting points to conventional associated circuitry or
electronic components, which, because they are conventional are not
described in full detail. The detailed circuit description of FIG.
2 fully describes all parts associated with the alarm control
module. The total system is a completely effective self-contained
system without the use of accessory equipment. However, accessory
alarm sensors or remote alarm indicating systems can be connected
to this system to further improve its effectiveness and
versatility.
ALARM INPUT "A" AND INPUT "B"
Input terminals C and L are connected to the input of the flip-flop
through resistor 12. Resistor 12 and capacitor 5 serve as an RF
filter network to suppress any radiofrequency currents that may
exist on their respective connecting wires. Diode 1 connects Input
Terminals A and O to the input of the flip-flop circuit. Terminals
B, D, K and N serve as the ground return for each of the four input
terminals aforementioned. When a closed circuit condition exists
between either Terminals A and C or L and O and circuit ground, a
low-resistance ground will be exhibited at the base of Transistor
19. Normally on transistor 19 in the flip-flop circuit will,
therefore, be shut off by that input circuit condition.
ALARM VOLTAGE INPUT
Terminal R connects to the alarm output of the ultrasonic intruder
detector module. The output of that module is a DC voltage
proportional to the amount of motion that the detector senses.
Resistors 72 and 71 and transistor 73 comprise a DC threshold
transistor switch. When a certain DC level has been exceeded at
terminal R, transistor 73 will switch on, causing a low-resistance
condition between collector and emitter connections of transistor
73. This DC threshold switching action also causes a low resistance
to ground condition at the input of the flip-flop circuit.
BISTABLE MEMORY
The system described herein has incorporated a flip-flop circuit
design for normally open alarm circuits. The particular design
techniques utilized cause the flip-flop to always come on in the
same state. When a closed circuit exists on its input, the
flip-flop changes state. The flip-flop remains latched in that
state until it is reset by the use of a separate signal. With
slight modification, the same design is extended to include both
normally open and normally closed input circuits simultaneously.
Elements 10 through 21 comprise the components used in the
flip-flop circuit. Resistors 10 and 11 serve as the collector load
resistors for transistor 15, the normally off transistor of the
flip-flop. Resistors 13 and 16 serve as the cross coupling
impedances from each collector to each other's base. Resistor 14 in
conjunction with resistor 13 determine the voltage threshold
characteristics of transistor 15. Resistor 17 and resistor 18 in
conjunction with resistor 16 determine the voltage threshold
characteristics of transistor 19. Resistor 20 serves as the
collector mode resistor for transistor 19. By intentionally making
the resistance of resistor 20 much larger than that of resistors
10, and 11, transistor 19 saturates more easily than transistor 15.
It is for this reason that transistor 19 is always the on
transistor in the normal state. Since transistors 15 and 19 are
cross coupled, the states of each are always opposite each other.
Therefore, one or the other is on, and one or the other is off.
This action causes current to flow always through diode 21. The
voltage drop across diode 21 remains essentially constant and
serves as back-bias to transistors 15 and 19, ensuring that the off
transistor is definitely off. Although the flip-flop shown herein
by way of example is designed for circuit closing alarm sensors,
conventional modification makes the flip-flop suitable for use with
circuit opening alarm sensors.
RELAY DRIVER
When an alarm signal triggers the flip-flop, transistor 9 turns on
due to current flow through resistor 11 and transistor 15 of the
flip-flop. Relay coils 6A and 7A are connected to the collector of
transistor 9. Therefore, one side of each of the relay coils is now
at a positive potential. When the other side of either of these
coils is grounded, that coil is energized. The position of function
selector switch 50 determines whether or not either of these relays
are grounded, enabling either or both of them to be energized when
the alarm trigger occurs.
RELAY 6 AND RELAY 7
Relay contacts 6B and 7B are shown in the deenergized state. When
coil 6A is energized, contacts 6B close, applying 120-volt AC power
to AC outlet IJ. When relay coil 7A is energized, contacts 7B
switch from position 1 to position 2, causing output terminals E
and F to change to an open circuit and output terminals G and H to
present a closed circuit. Remote alarm control apparatus connected
to either of those output terminal pairs sense the change of state
and actuate their particular alarm modes. Diode 8 protects
transistor 9 from any inductive kickback surges from relay coils 6A
or 7A.
HORN DELAY TIMER
It is normally very difficult to design a circuit with a time delay
range ratio as high as the circuit designed in this system and to
maintain a linear time scale on the time delay adjustment control.
The time delay circuit of the present invention resets itself
instantaneously and can immediately resume the same timing cycle
with a very small amount of error. Circuit components 22 through 30
serve as the adjustable delay timer. Normally capacitor 24 is
grounded through resistor 23, diode 22, and flip-flop transistor
19. Adjustable resistor 30 and resistors 29 and 28 serve as a
variable voltage bias network in the emitter circuit of transistor
26. Transistor 26 is normally off, since the emitter voltage is
higher than the base voltage in the no alarm state. When an alarm
trigger occurs, transistor 19 shuts off, causing diode 22 to
reverse bias, thereby ungrounding capacitor 24, which begins to
charge towards B+ through resistor 25. When its base voltage
exceeds its emitter voltage by 0.6 volts, transistor 26 turns on.
If variable resistor 30 is set at maximum resistance, the greatest
amount of voltage exists at the emitter of transistor 26. That
condition establishes the maximum time delay as established by the
RC product of resistor 25 and capacitor 24. At that time, capacitor
24 will have accumulated enough charge so that its potential is
higher than the emitter potential, and transistor 26 turns on. The
delayed alarm trigger signal, therefore, is located across resistor
27. The time delay can be varied between minimum and maximum limits
established by the variation of emitter potential on transistor
26.
HORN RELAY CIRCUIT
Elements 32 through 41 comprise the horn relay circuit. Resistor 32
establishes the base current flow for transistor 33. When an alarm
signal exists at the output of the adjustable horn delay timer
circuit, transistor 33 is turned on causing the collector potential
of transistor 33 to raise from zero to B+ voltage. Diode 34 couples
this plus voltage to the horn flashing circuit. The simple
electronic circuit used in conjunction with the horn relay coil
causes a flasher action. The flashing rate and flashing duration is
easily adjustable and can be varied over a wide range. The power
consumption is very minimal when compared to standard flasher
devices that typically work on a thermal heating effect of a
bimetallic contact arrangement. There is an order of magnitude
improvement in the consistency of the timing factors under the
conditions of varying supply voltage as compared to the typical
thermal flasher unit. Transistor 38, resistors 37 and 40, capacitor
39 and unijunction transistor 41 comprise an electronic
multivibrator circuit, causing relay coil 36A to be energized and
deenergized at a predetermined rate. Relay contacts 36B close and
open, respectively causing horn 74 to be energized and deenergized.
RC product of resistor 40 and capacitor 39 determine the on time of
the multivibrator circuit. Diode 35 protects transistor 38 from
inductive kickback voltages from relay coil 36A. The relay circuit
can be energized only when it is connected to ground. This again
depends on the position of function selector switch 50.
FUNCTION SELECTOR
Function selection used in this apparatus eliminates the use of a
complex multiple-pole selector switch. The combination of diodes
and a one-pole switch yields an extremely simple solution to a
typically difficult problem. There is a suitable diode
configuration for any combination of functions that one desires to
be able to select. Function selector switch 50 enables relays 6A,
7A and 36A in the following manner. In position 1 relay 6A is
grounded, and relays 7A and 36A are ungrounded due to diode 47
being back-biased. In position 2 relay 36A grounds directly, relay
6A grounds through diode 47 being forward biased, and relay 7A
remains ungrounded due to diode 48 being back-biased. In position 3
relays 6A, 7A and 36A are grounded due to diodes 47, 48 and 49
forward conducting. In position 4 relay 7A grounds directly, and
relays 6A and 36A are ungrounded due to diode 49 being back-biased.
The function selector, therefore, allows various combinations of
events to occur when the alarm system has been triggered.
INSTANT ALARM CIRCUIT
Diode matrixes of the function switch and Input B produce an
all-function enabling override regardless of switch position. This
second logic loop forms the basis for many of the unique features
and functions that are displayed in this equipment's design. This
section of circuitry also overrides the adjustable time delay
circuit function. Circuit components 31, 2, 3 and 4 cause an
overriding chain of events to occur. Resistor 31 maintains input
terminal A at a positive potential, back biasing diodes 1, 2 and 4
to maintain an out of circuit condition. When a closed circuit
exists between terminals A and B or terminals N and O, voltage at A
drops to zero, causing diodes 1, 2 and 4 to conduct. Since the
anode of diode 4 is connected to position 3 of function selector
switch 50, relays 6A, 7A and 36A are effectively grounded. The
conduction of diode 1 causes the flip-flop to be triggered to the
alarmed state. Therefore, relay 6A and 7A are instantly energized,
regardless of the position of function switch 50. The conduction of
diode 2 causes the emitter potential of transistor 26 to be dropped
to close to zero volts, which supercedes any preset timing delay
voltage in the circuit; the horn relay circuit is energized
instantaneously. Relay 36A also is energized instantaneously due to
the fact that it grounds through diode 4, regardless of the
position of function switch 50. The instant alarm input, therefore,
triggers all output circuits as long as a closed circuit exists at
the input terminals. When an open circuit condition is
reestablished, the output circuits that remain energized will be
determined by the position of function selector switch 50. The
flip-flop is still in the alarmed state.
RESET CIRCUIT
The present method of reset timing does not allow the system to
become completely disarmed. An alarm output will always occur for
at least 5 seconds for any trigger caused by any sensor that is
connected to the input of the system. There is no need to
incorporate keylock switches and other such devices in order to
provide a secure system.
The flip-flop remains in the alarmed state irregardless of which
input circuit has triggered it; the trigger can be of a momentary
or continuous nature depending on the source. A means of resetting
the flip-flop must be provided. Two conditions must exist before
the flip-flop can be reset; a specific time interval must exist
after the horn circuit has been energized, and all input circuits
must be cleared. Components 43, 44 and 45 act as a timing pulse
circuit, determining the time interval before the flip-flop can be
reset. When the horn circuit has been energized, capacitor 44,
begins to charge through resistor 43. The voltage versus time
relationship established by this RC product determines the amount
of time delay. Unijunction transistor 45 does not fire until reset
switch 46 has been depressed. Even if reset switch 46 is depressed
before or at the time of alarm trigger, a reset pulse is not
generated until capacitor 44 charges to the firing potential of
unijunction transistor 45. At that time a positive pulse will
appear at the base of flip-flop transistor 19, causing the
flip-flop to be reset to its original state, with transistor 19 in
the on condition.
AC PRIMARY CIRCUIT
Reference 51 connects to 120-volt AC 60-cycle power source; the
third wire represents the equipment ground return. Switch 53 acts
as the AC power on and off switch. Fuse 54 will open circuit due to
fault currents in either transformer 58 of AC outlet IJ. This
protects all internal wiring as well as relay contacts 6B against
an over current situation. Resistors 55, 56, and neon lamp 57 are
used to indicate when AC power is applied to the electronic
circuitry. With 120-volt AC applied across the primary of
transformer 58A, a voltage stepdown to 12 volts AC occurs at
secondary 58B. Secondary AC voltage is rectified by diodes 59, 60,
61 and 62 to produce a DC output voltage of approximately 19 volts.
Capacitors 63, 64 and 65 filter out AC ripple from the
rectification process to produce an acceptable pure DC voltage,
referred to as B+ voltage. B+ voltage is fed to all active circuits
contained in the alarm control module and is fed to terminals Q and
S to supply power to auxiliary equipments.
INTERNAL STANDBY POWER
Elements 66 through 69 comprise the internal standby battery power
system. Switch 68 connects or disconnects battery 69 from the
circuitry. It also connects or disconnects the B+ voltage to
terminals which feed DC power to auxiliary equipment. Battery 69 is
a nickel cadmium battery capable of being charged and discharged
many times. With switch 68 on, resistor 67 determines the trickle
charge current. Diode 66 is back-biased when AC power is applied;
therefore, the rectified AC supplies all circuit power, and battery
69 is effectively disconnected from the circuit and is in a trickle
charging mode. When AC power fails, B+ voltage begins to drop. When
it drops 0.6 volts below the battery voltage, diode 66 conducts and
automatically connects battery 69 to the B+ line, allowing the
battery to supply uninterrupted power to the electronic circuitry.
The intentional voltage difference between the two sources of DC
power allows the standby power switchover arrangement to be
utilized.
DC CIRCUIT TO ULTRASONIC MODULE
Switch 70 when closed applies the battery voltage to terminal P to
enable and supply standby power to the ultrasonic intruder detector
module. When switch 70 is opened or in the off position, the
ultrasonic intruder detector module is disabled or disarmed and,
therefore, is not capable of triggering the alarm control module,
irregardless of the positions of switch 68 or 53.
Switches 53 and 68, being in the off position, disarms the complete
system. All alarm inputs are armed when either switch 53 or switch
68 in on.
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