Abstract: An overheat detector comprises an optical fiber connected at one end to a light source and at the other end to a photodiode for monitoring the light level transmitted through the fiber. When the light level falls below a predetermined threshold due to melting of the fiber, an alarm signal is output. The temperature at which the alarm signal is output depends upon the material of which the light conducting part of the fibre is constructed.

Abstract: A combination audio and visual alarm system for selectively generating either audible, or visual, or combined audible and visual alarm signals, including a sound transducer device having a blocking capacitor connected thereto, a polarity-responsive electrical lamp, and a two-conductor circuit connected with the sound transducer device and with the lamp. In addition, there is a source of d. c. and a source of audio signals. A switch connects the two-conductor circuit to either the d.c. source or the audio source, thereby to enable simultaneous operation of the sound transducer and the lamp upon energization of the circuit by the source of audio, or to enable sole operation of the lamp when the circuit is energized by d.c.

Abstract: An intelligent security assessment system includes a multiplicity of sens for detecting intrusion into an area. Each of the sensors operates on a different principle to detect intrusion. For example, sound, vibration, infrared, microwave and light level sensors are used. A computing system receives the outputs of each of the sensors and is programmed to provide an output based upon an algorithm that minimizes the likelihood of a false indication of intrusion by the intrusion sensors. Each sensor has an on and an off state and the computing system assigns a weighting factor for each sensor that is in the on state. The computing system sums the weighting factors and compares this sum to a reference and then provides a further output when the sum exceeds the reference. This computing system output is utilized to activate an additional intrusion detector such as an ultrasonic detection system and also to activate a video surveillance camera for observance of the area where the intrusion is indicated.

Abstract: A self-diagnostic circuit for use in alarm systems and the like, of the kind having a plurality of alarm detection switches connected in a loop, indicators associated with each of the switches for indicating locally the detection of an alarm condition and a central controller for reversing voltage polarity in the loop whenever an alarm condition is detected by one of the switches. The self-diagnostic circuit comprises: a first switch for detecing an alarm condition connected in an alarm loop; a second switch automatically activatable in response to operation of the first switch; an alarm indicator automatically operable in response to activation of the second switch; and, an automatically operable circuit for preventing deactivation of the second switch until after diagnosis of alarm system operation, even when the first switch no longer detects the alarm condition. Any such first switch exhibiting erratic switching behavior can be easily identified by continued operation of the associated alarm indicator.

Abstract: A tamper evident closure apparatus is described in which a closure sensing switch is positioned inside of a container for nonprescription drugs and the like for producing a lid removal signal upon the removal of the lid from the container. A sound signal generator responds to the lid removal signal and generates an auditory sound of safety signal informing the person opening the container that the lid has not been previously removed. A safety circuit also responds to the removal of the lid and inhibits the sound signal generator from responding to a second or subsequent lid removal signal so that the replacement and subsequent removal of the lid will not trigger the generation of a second sound of safety signal.

Abstract: The failure alarm device for an appliance of the present invention include a first alarm for indicating an abnormality if an abnormality should occur in the appliance main body, and a second alarm for indicating an abnormality if an abnormality should occur in the appliance main body and when the first alarm fails to function.

Abstract: An individual source identification of several signal providers or pick-ups with closable contacts disposed in a twin-wire signal line, in particular for fire detectors in fire alarm systems. The signal pick-up system allows to distinguish actuation of individual sensors separately and apart from a short circuit formation. The fire alarm system also allows connection to automatic sprinkler devices. The fire sensor system is easy to install in that the individual settings of the individual detectors at a construction site are minimized.

Abstract: An intrusion detection loop employing an end-of-line resistor that operates with a voltage window. As the voltage window is increased, the sensitivity of the system decreases. As the window is decreased, the sensitivity of the system increases. By utilizing two comparators each having one input coupled to the loop, one can specify one voltage window when the system is disarmed and hence place the system at maximum sensitivity thereby detecting any borderline problem. In any event, the same two comparators operate to provide a different voltage window when the system is armed and hence desensitizing the loop and therefore reducing alarm probability. In this manner one can determine during the disarmed condition that the loop is operating with a borderline resistance and still employ the system in the armed condition to assure that there will be a reduced alarm probability in view of an undesirable change of the loop resistance.

Abstract: An adapter module for converting a Class B alarm system to Class A operation. The module includes a first pair of terminals connected to corresponding terminals of a Class B control panel, and second and third pairs of terminals to which Class A alarm loops are connected, one terminal of each of the second and third pairs of terminals being directly electrically connected to a separate terminal of the first pair of terminals.

Abstract: The present invention relates to a signal selector which selects a signal for control of various operating parameters in a process facility. The system includes a display and first and second sensors each providing a signal representative of a single controlled parameter. The first signal is preferred as a control signal for the parameter. A switch is arranged on the display for manually selecting between the first and second signals or for selecting an automatic selection mode. The system further includes an arrangement for determining if the first signal is unacceptable including comparing the first and second signals to one another and to a first pre-selected threshold value and either by comparing the first signal to a second threshold value or performing a second comparison of the two signals. The system automatically switches to the second signal when the first signal is unacceptable when the switch is in the automatic selection mode.

Abstract: An improved process measurement system is disclosed which provides automatic signal evaluation and transfer in connection with redundant signals generated from a common data source over two input channels and one output channel. The two input channels are monitored by a series of three comparators which compare real time values of the signals on the two channels, and as well, a real time and delay value from each channel.

Abstract: An intrusion detector has a first sensor for monitoring a first condition and a second sensor for monitoring a second condition in a space to be protected against intrusion; a change in the condition sensed by the first sensor in a target area causes the second sensor to be aligned with the same target area; and if both sensors indicate a change in the respective conditions that they monitor an intrusion is indicated.

Abstract: A method of transmitting signalling along a bidirectional digital transmission link consists in transmitting from an intermediate equipment of the link a signalling message in two parts. One is a characterizing part the form of which depends on the signalling type and which is substituted for data of one of the digital bit streams carried by the link in the direction from one of the terminals referred to as the processing terminal. The other is a localizing part whose form is independent of the signalling type and which is substituted for data of the digital bit stream carried by the link in the direction towards the other, so-called relay terminal. The relay terminal responds by sending an acknowledgement message to the processing terminal, the time-delay of this relative to the characterizing part being used to identify the sending equipment. A signalling message transmission circuit controls switching circuits inserted into the paths of the digital bit streams carried by the link.

Abstract: A fail-safe alarm system includes a device which allows current to flow in only one direction to insure that the supervisory current in an alarm circuit is flowing in the intended direction rather than in a wrong direction caused by a miswiring.

Abstract: A single-wire loop alarm system in which an identification module is placed across each alarm switch. Any module which is across an open switch is powered by the loop current and, in response to a pulse count in the loop representing its address, changes the loop impedance in order to report on its status. The loop current may alternate in direction so that oppositely poled modules may be used, thus allowing a larger number of powered modules to accommodated at the same time.

Abstract: A self-powered sensor for a closed-loop security system includes a self-powered sensor network which provides a switch-actuating signal upon the detection of a physical condition. An electronic switch, which is in a normally closed position, is connected between the positive and negative poles of a closed-loop security system and opens the loop upon receipt of the switch-actuating signal thereby triggering an alarm. The self-powered sensor network may include a voltage doubler for converting the AC output of a transducer to a DC voltage of an amplitude sufficient to open the switch. When the switch is opened, voltage from the closed-loop security system becomes available to power a visible or audible alarm identifying the sensor that opened the loop.

Abstract: A single-wire loop alarm system in which the status of each alarm switch can be determined and which is relatively immune to the effects of noise. False alarms are avoided by incorporating an integrator in the loop potential test circuit; during polling, however, the integrator is switched out. Low-frequency noise is discriminated against by verifying the existence of an alarm condition; the loop current is doubled and, if the alarm condition is being caused by an impedance-introducing open alarm switch, the loop voltage change should double. Polling is made more reliable by relying on a "window" test, rather than a simple threshold test.

Abstract: A light control apparatus for a vehicle is integrated with headlamp driving relays, a light sensor, a lighting switch which selects a manual mode or an automatic mode, and a control unit which controls the relays in accordance with the light sensor output when the lighting switch selects the automatic mode and turns on or off the headlamps. Two power source systems and two headlamp driving systems are provided. The signal level of a given terminal of the control unit is detected and is input to the microcomputer of the control unit. The microcomputer judges whether or not trouble has occurred by detecting a level difference. An alarm indication is given by a lamp or a buzzer if trouble is detected.

Abstract: Walk through test system for testing devices such as pull stations, smoke detectors, alarm bells and the like for alarm and trouble conditions without the assistance of a central panel operator. The devices are connected in a loop or loops distributed throughout one or more zones remote from a central panel. Alarm and trouble conditions are detected at the central panel. When a device is placed in alarm by the workman, a coded alarm is sounded which is aurally detectable by the workman at the location of the device, remote from the central panel. The coded alarm identifies the zone loop in which the device is connected. When a trouble condition is created in a loop by the workman, an alarm is sounded which is aurally detectable at the location of the loop, remote from the central panel. The alarm is coded to indicate to the workman that a trouble condition has been detected at the central panel.

Abstract: A composite detector includes a plurality of sensors of the same or different types, a plurality of analog switches connected to outputs of the plurality of sensors, and an operation circuit, such as an operational amplifier. The sensors detect physical phenomena such as heat, smoke and gas according to different principles of detection, and output analog detection signals. The analog switches are controlled by a selector operated with a control signal from a central monitor or magnitudes of outputs from the plurality of sensors. The operation circuit calculates outputs from the plurality of analog switches.

Abstract: An emergency alarm system incorporating both signal generation and voice annunciation capabilities, for installation in a building or other structure. The system includes a standard fire alarm control panel and one or more loud speakers, each speaker having a series blocking capacitor. The panel has conventional supervisory circuitry and sensing/alarm terminals connected therewith, adapted to indicate an alarm condition when conditions warrant, as by signals received on multiple sensor lines that also communicate with the panel. A signal generator and amplifier are arranged to drive the speakers, under alarm conditions. There is provided a circuit-failure indicator including an electrical switch and an electro-responsive actuator device connected with the signal generator. The electro-responsive actuator device, when energized by the signal generator, maintains the switch in a closed-circuit condition.

Abstract: A moisture detector for detecting the presence of moisture between two electrodes includes an AC sensing network coupled to an indicator circuit by an opto-isolator to isolate impedances between the two circuits. The battery life of the detector is extending by a unique pulsing technique that creates current drain in the sensing circuit for only brief intervals of time. The pulsing technique enables the indicator circuit to keep an electronic switch in a closed-loop security system in an on state.

Abstract: A light transmission system for a train which includes sub-train compositions. Ths subtrain compositions each have end vehicles, one of which forms a head and the other of which forms a tail with respect to the moving direction of the train. The end vehicles each include a central station responsive to a first command signal from the front platform of the train to perform a central function for producing a second command signal and responsive to the second command signal to perform a terminal function which passes therethrough any input signal when an adjacent central station is found to be connected thereto and which returns any input signal when no adjacent central station is found to be connected thereto, thereby forming a complete signal transmission path in the train.

Abstract: A multistationed integrated life safety system in which each station will be situated at a diffferent location and have complete capabilities in terms of local fire protection, fire detection, control and/or monitoring and controlling the security of an area. Each station communicates with four adjacent stations so that when an event occurs at one station, that station is programmed to cause that information or that new status to be transmitted to each of the four adjacent stations. Thus, each station will be interconnected or networked to four other stations to provide multiple location control and annunciation so that each station may act independently.

Abstract: A central protection system suitable for the protection of a building from fire and other hazards includes a set of environmental sensors and circuitry for interrogating the sensors. The system also includes communication and control lines, as well as monitoring circuitry having individual channels coupled to respective ones of the communication and control lines. An inaudible pilot tone of subsonic frequency may be coupled to a communication line, and the corresponding channel of the monitoring circuit includes a detector of the pilot tone. A circuit for the generation of evacuation signals and fire brigade signals is composed of two sections coupled in tandem, and includes sequencing circuitry for the recycling of tones produced by the respective sections.

Abstract: A plurality of different types of operating systems in buildings organized in geographical groups, each group having a local service office, are monitored at both the local offices and central office for the presence of performance conditions and conditions indicative of an alarm condition.

Abstract: An alarm message generation and broadcast system having supervision including an alarm message generation circuit for generating an alarm message, an output for receiving the alarm message so that the alarm message can be broadcast in response to an alarm event; and a supervision circuit connected to the alarm message generation circuit and responsive to the alarm message for providing a trouble signal when the alarm message is not properly received by the supervision circuit.

Abstract: Measuring stations or locations are connected in cascade to signal lines and transmit measured or measuring values to a central signal station at which the measured values are linked or appropriately processed so as to obtain distinct malfunction or alarm signals. Upon activation of the monitoring system all measuring stations are disconnected by a change in voltage appearing on the signal line. Then, the measuring stations are reconnected to the signal line in a timewise staggered fashion by means of switching elements present at each measuring station in such a manner that each measuring station additionally reconnects a subsequent measuring station to the line voltage after a predetermined time-delay. Address storages are present at the measuring stations and are charged or occupied in a predetermined sequence by the central signal station with addresses associated with the individual measuring stations.

Abstract: A multiple-sensor status monitoring system for monitoring the status of an area while avoiding false alarms and detecting and identifying faulty sensors. The system uses a timer and logic to avoid false alarms by generating an alarm signal only if two sensors give a response within a preselected interval of time. The system employs latching storage elements to keep a record of which of the sensors have made spurious responses, and a visual display to give a trouble warning respecting those sensors.

Abstract: Alarm system providing a signal by turning on alarms, lights, sirens, automobile horns or wake-up signal based on interruption of a monitor loop. Monitor loop includes a resistor which connects to the inputs of a low-power low-offset voltage dual comparator for providing an ON signal for turning on a buzzer alarm and also for driving a relay through a switching transistor. The relay can include normally closed and normally open contacts for operating an existing closed loop or open loop device or circuits. The alarm system also includes a line-adjust circuit for adjusting the particular resistance and the monitor loop, a latch circuit for latching the buzzer and relay in an ON position based on circuit interruption, and includes internal power source as well as provision for external power.

Abstract: In an instrument system consisting of a transmitter in one location and a receiver in another location connected by a transmission medium, fail-safe operation is obtained by restricting the output of the transmitter to well-defined levels and interpreting any substantial departure of the received signal from these well-defined levels as a failure. When a failure is detected, alarms or other equipment may be activated, including a control circuit which causes replacement of the defective transmitter or transmission medium, thereby restoring the system to service. An embodiment wherein the transmitter is an admittance-responsive transmitter in a two-wire current loop for monitoring the condition of materials is described.

Abstract: There is disclosed a fire alarm system wherein a plurality of fire detectors are connected to each alarm line and a light emission diode is connected in series between an alarm line and an electric source, said light emission diode indicating the actuation of any of the fire detectors, said system being capable of monitoring the alarm lines for breakage or disconnection without interruption of its fire monitoring function. This fire alarm system comprises a pulse oscillator; a switching circuit; a voltage detection circuit; two light emission diodes; a delay circuit; means for forcibly turning on the switching circuit; a capacitor; and a high resistance resistor.

Abstract: A monitoring system for a protection loop that has a plurality of switches in series utilizes modules with inexpensive diodes and resistors, and is conveniently and easily added to existing burglar alarm circuits and loops. A monitoring module that includes a diode and a paralleled resistor is connected across each switch. First and second interrogating signals are alternately applied to the protection loop. First comparator circuit means provides an output in response to each first interrogating signal when one of the monitored switches in the protection loop is open as indicated by the response of the module resistors; and second comparator circuit means provides an output in response to each second interrogating signal when more than one of the monitored switches in the protection loop is open as indicated by the response of the module diodes.

Abstract: A tool setting-aid comprising an anodized aluminum "button" and a support therefor is set up at a predetermined datum position on the worktable of a computer controlled machine tool, the machine program including a check cycle which sends the cutting tool around and over the button or, if the tool is oversize or set wrongly, into contact with the button. The button is supplied with electrical current via a cable having a resistor coupled to the button end thereof by an electronic detector circuit which includes a sensor for detecting current increase due to contact between button and cutting tool and a sensor for sensing interruption of such current due to cable breakage or a failure to properly connect it to the setting-aid.

Abstract: Apparatus for indicating a break in the lines leading from a base station to a monitored instrumentality. Two pairs of wires conduct signals to each contact of a normally open switch-like element in the monitored instrumentality (the closure of which signifies an alarm condition) and return these signals to the base station. The presence or absence of the return signals at predetermined times indicates the condition of the lines and also an alarm condition, even if one of the lines leading to the instrumentality is broken.

Abstract: The integrity of a two-conductor transmission line, over which d-c energizing voltage is supplied to a series of shunt-connected detectors (such as fire and/or smoke detectors) and which line is terminated by an end-of-line capacitor, is monitored and repetitively tested by periodically and momentarily interrupting the application of the d-c energizing voltage to the transmission line or conductor pair, while at the same time connecting a resistive load across the line's input end to provide a discharge path for the capacitor. If the integrity is normal, meaning that the line is continuous and not open, and has no excessively high series resistance or excessively low shunt resistance, and also meaning that the capacitor is functioning normally and is not deteriorated, the capacitor will discharge very little during each test and will maintain a relatively high voltage across the resistive load.

Abstract: A security system including a plurality of sensor loops, each having a plurality of detectors and associated detector identification devices which upon actuation produce analog detector signals of different amplitude for each detector in such loop to identify the actuated detector. The sensor loops each have a common loop output which is connected to a different one of a plurality of input terminals of an analog to digital converter and multiplexer circuit which includes a multiplexer switching circuit for selectively switching between such inputs and which converts the selected analog detector signal to a digital detector output signal. The outputs of the analog to digital converter are connected to a digital data processor circuit, such as a microprocessor computer, for processing the digital detector signals to determine which detector produced such signals and to generate a corresponding output signal that may operate an alarm means such as a bell or indicator light.

Abstract: A microcomputer controlled circuit arrangement for sensing fire and burglar alarms in the presence of undesired fault conditions, such as opens or shorts, on monitored communication lines. The arrangement includes transistor-resistor sensing circuitry which is shared by a plurality of monitored communication lines, each of which comprises a first pair of conductors connected to a first contact of an alarm sensor and a second pair of conductors connected to a second alarm sensor contact. The sensing circuitry is connected through a multiplexer to each one of the lines one at a time under control of the microcomputer to detect any fault thereon and any alarm provided by the sensor contacts. The sensing circuitry is responsive to impedance conditions on the four conductors furnishing a plurality of output voltages which are examined by comparators that, in turn, generate combinational logic voltages signifying the alarm-fault state of a monitored line.

Abstract: An electrical protection system including a plurality of suppressor units each activatable by either a first or a second electrical current responsive activator to suppress abnormal condition. The system further includes a supervisory electrical current source, an activation electrical current source, a first connector circuit connecting all of the first activators in series and a second connector circuit connecting all of the second activators in series. A control circuit connects the supervisory source in parallel with the first and second connector circuits so as to provide in each a predetermined supervisory current that is insufficient to energize the activators.

Abstract: In a central station alarm system the alarm sensors associated with a particular subscriber's premises are monitored by a local control unit associated with those premises and controllable by the subscriber. The local control unit automatically reminds the subscriber when he is supposed to close the premises and turn on the system. The local control unit allows the subscriber to change his expected closing time. The local control unit may also perform various other functions such as automatically cutting off power to low priority alarm sensors during a prolonged power failure, automatically cancelling any audible alarm indication silence commands when there are no alarms to silence, and automatically forming a bridge connection between the remote ends of two communication circuits when there is a break in either circuit.

Abstract: A fire extinguishing apparatus and an actuating system. The actuating system includes a plurality of actuators connected in parallel and a source of electrical signal for said actuators. Each actuator is connected in parallel with a device whose resistance decreases with increasing current through the device.

Abstract: The detection of events such as illegal entry detection, or the occurrence of predetermined hazards are detectable by a system including a circuit loop 2 which incorporates event actuatable switches 1, 35, 37, 38. Each switch has associated therewith means (9, 36, 37a, 39) for both maintaining electrical continuity in the loop, following operation of the associated switch and for producing an electrical condition in the loop which is indicative of switch operation. A control circuit 7 is arranged to respond according to the condition produced and produce an alarm characteristic of the condition.

Abstract: In a central station alarm system the alarm sensors associated with a particular subscriber's premises are monitored by a local control unit associated with those premises and controllable by the subscriber. The local control unit automatically reminds the subscriber when he is supposed to close the premises and turn on the system. The local control unit allows the subscriber to change his expected closing time. The local control unit may also perform various other functions such as automatically cutting off power to low priority alarm sensors during a prolonged power failure, automatically cancelling any audible alarm indication silence commands when there are no alarms to silence, and automatically forming a bridge connection between the remote ends of two communication circuits when there is a break in either circuit.

Abstract: A safety circuit which connects a condition responsive circuit to a cyclic signal detecting circuit. In order to provide the cyclic signal detecting circuit with a continuous cyclic input, the condition responsive circuit and a cyclic redundancy checker is provided. The cyclic redundancy checker identifies a specific series of logic bits from the condition responsive circuit and responds favorably only to that series of logic bits. If any other series of logic bits occurs, the cyclic redundancy checker of the system ceases to function, thereby causing the cyclic signal detecting circuit to cease to function and it in turn opens a series contact to deenergize a critical load in a control system.

Abstract: For use in combination with a turbine control system, an automatic signal selector to assure selection of a valid signal representation of an operating parameter of the controlled turbine. Redundant sensors provide multiple redundant signals representing the operating parameter. Each signal is applied to a corresponding range detection circuit which generates an alarm signal whenever the sensor signal is higher or lower than preselected values. Simultaneously, each sensor signal and each alarm signal is applied to a selector network which selects one of the sensor signals as a valid signal for turbine control purposes. Thus, if any one of the alarm signals is present, indicating that at least one sensor signal is outside the preselected range, the highest valued sensor signal is automatically selected for control purposes. On the other hand, if no alarm signals are present, the control signal is automatically selected to be an intermediate valued one of the sensor signals.

Abstract: An Alarm system for furnishing an alarm signal in response to unauthorized entry through a passage connecting the outside to the interior of a building, wherein a first detecting device furnishes a first output signal when sensing the presence of a person in a first portion of the passage. A second detecting device nearer the outside of the building furnishes a second output signal when sensing the approach of a person. An evaluating circuit receives the output signals and initiates an alarm signal only if the second output signal is furnished prior to the first output signal.

Abstract: In a fire alarm system individual fire alarms are connected in series by reporting lines with a central signal station. In order to be able to connect a greater number of fire alarms with the individual reporting or signaling lines and/or in order to be able to dispatch an increased amount of current through the reporting lines, the reporting or signaling lines from the last fire alarm of a line are returned back to the central signal station in the form of a ring circuit or loop. Upon the absence of signals at a reporting line an interrogation device is reversed, so that there can be ensured that in the event of a line disturbance or breakdown of a fire alarm the remainder of the fire alarms still can be utilized for giving a signal. The individual fire alarms are structured such that during assembly the inputs and outputs can be mutually interchanged.

Abstract: A control system for coupling redundant logic channels while maintaining electrical and physical isolation between channels. The separate redundant logic channels each include an electro-optic modulator, which are connected by fiber optic links, with system condition sensors generating signals which are applied to the electro-optic modulators to control the light transmission characteristics of the electro-optic medium in response to a predetermined system condition. A light source is connected by input fiber optics to the logic channels, and output fiber optics connect the logic channels to a light detector.

Abstract: An alarm, safeguarding and monitoring system for a room zone includes a plurality of sensors disposed at different positions and responsive to different physical phenomena, such as an ultrasonic sensor, an infrared sensor and a microwave sensor. The sensor outputs are individually coupled to majority decision, central processing unit and alarm generator circuits by a plurality of redundant signal links to minimize malfunction in the event of disruption or tampering.

Abstract: An alarm sensing loop for selectively monitoring at least first and second alarm sensors includes terminals for connection to a source, a selection circuit connected to the terminals and having first and second states, a first alarm sensor connected to the selection circuit to be supervised continuously when the selection circuit is in its first and second states, a second alarm sensor, and a selection state sensing circuit for allowing supervision of the second alarm sensor when the selection circuit is in its first state and for preventing supervision of the second alarm sensor when the selection circuit is in its second state.