Abstract: In an arrangement for supervising and controlling field light units (20) at an airport, a regulator provided with a monitoring unit for power supply and for monitoring the light units is arranged individually for each light unit (18,20) to regulate the light intensity of the light units and to receive information as to their operational status. In a preferred embodiment, each light unit comprises two separate light sources that can be alternately and separately connected into circuit in case of failure to either of the light sources. Each light unit is provided with an electronic unit including a regulator, monitoring unit, and modem for power supply to the light unit and for monitoring the operation of the light unit. Each light unit is individually addressable from a control central for the airport. A ground traffic control system can be integrated into the field lighting system by connecting suitable presence detectors to the system.

Abstract: A lamp monitor provides a sense resistor for each lamp circuit as a special sense terminal member with a series resistance and sense terminals connected to a circuit board in a lamp monitor module. A multiplexing arrangement allows selection of the circuit to be monitored. The monitor samples the voltage across the series resistance by first connecting a capacitor across the sense terminals to be charged to the voltage and then disconnecting the capacitor from the sense terminals and connecting it across the input of an amplifier. The voltage across the lamps is sensed to provide a ratiometric reference for the digitizing of the amplifier output in an analog to digital converter; and a digital computer corrects the input digital signal with a stored non-linear normalization factor relating current to voltage in the lamps.

Abstract: A lamp monitor provides a sense resistor for each lamp circuit as a special sense terminal member with a series resistance and sense terminals connected to a circuit board in a lamp monitor module. A multiplexing arrangement allows selection of the circuit to be monitored. The monitor samples the voltage across the series resistance by first connecting a capacitor across the sense terminals to be charged to the voltage and then disconnecting the capacitor from the sense terminals and connecting it across the input of an amplifier. The voltage across the lamps is sensed to provide a ratiometric reference for the digitizing of the amplifier output in an analog to digital converter; and a digital computer corrects the input digital signal with a stored non-linear normalization factor relating current to voltage in the lamps.

Abstract: A vehicle indicator system is set forth for a vehicle that has first and second instrumentation indicator lamps for indicating the condition of first and second vehicle systems. Instead of the first indicator lamp having a backup lamp in case the first indicator lamp burns out, the second indicator lamp serves a dual purpose as the backup lamp for the first indicator lamp.

Abstract: Process for signalling malfunction protection in decentralised traffic-light installations having a signalling malfunction protection (SSP) and evaluation assembly (AWP) in a node control unit (KS) and having a plurality of PLS units (PLS modules M1, M2, . . . ) which each have peripheral lamp switches and sensors and a data transceiver, which together form an LMP assembly, as well as transformers and rectifiers for associated signal generators and groups of signal generators (SG) on the respective traffic-light poles (SGM1, SGM2, . . . ). The node control unit (KS) is connected to the PLS modules (M1, M2, . . . ) with a power and a data line (EDL). In addition to the customary signalling malfunction protection, the operativeness of the individual PLS modules and LMP assemblies (M1, M2, . . . ), respectively, is cyclically tested irrespective of the momentary signalling status. With each complete telegram cycle (TZ1, TZ2, . . .

Abstract: A light bulb tester includes a body having first and second opposite ends. A pair of parallel cylindrical electrically-conductive wire probes on the first end are spaced apart a distance of from about 4.5 mm to about 6.0 mm, said distance including the widths of the two probes and the length of the gap formed between them. A pair of male and female nine-volt battery contacts are attached on the second end of the body so that the tester may be powered by a standard battery of the 9V (household transistor) size. The tester is used for testing a bulb of a holiday light bulb string of the standard type having a plurality of bulbs in sockets wired in series. The bottom of each socket forms an aligned pair of apertures or a slot leading to a pair of electrical socket contacts inside the socket. There is enough room in the apertures (or slot) to insert the probes and to connect them to the socket contacts in order to test the bulb while it remains in the socket.

Abstract: A circuit for monitoring electrical loads, e.g. lamps especially in motor vehicles, comprises a power supply line (14) for supplying electric current for illuminating a lamp (10, 12), and means (58) for providing a reduced electric current through the lamp when not illuminated. A resistor (24) is in series with the lamp, and a comparator (40) is arranged to compare the potential of a point between the resistor and the lamp with a reference potential when the lamp is not illuminated for generating a warning signal in the event of lamp failure. A further power supply line (48) is also provided, and means (50) for establishing a fixed potential difference between the further and the first power supply lines. The comparator is arranged such that the fixed potential difference provides a constant voltage power supply for the comparator.

Abstract: Monitoring of trailer indicator lights includes a flasher pulse generator provided for generating, upon the switching on of a direction signalling switch, fixed pulse frequencies which can be changed over as a function of deviations of the load connected to the flasher pulse generator from its nominal load. The monitoring is carried out without requiring a change over of the flasher pulse generator to a "trailer mode" of operation. When the trailer is electrically connected, and upon the failure of one of the trailer indicator lights which are to be switched on and operated via a separate voltage supply at the frequency of the flasher pulse generator, one of the indicator lights of the towing vehicle is isolated from the electrical load of the flasher pulse generator. As a result of this simulated light failure, the frequency generated by the flasher pulse generator is changed over the imminent generation of a control signal to the vehicle driver.

Abstract: A lamp monitor provides a sense resistor for each lamp circuit as a special sense terminal member with a series resistance and sense terminals connected to a circuit board in a lamp monitor module. A multiplexing arrangement allows selection of the circuit to be monitored. The monitor samples the voltage across the series resistance by first connecting a capacitor across the sense terminals to be charged to the voltage and then disconnecting the capacitor from the sense terminals and connecting it across the input of an amplifier. The voltage across the lamps is sensed to provide a ratiometric reference for the digitizing of the amplifier output in an analog to digital converter; and a digital computer corrects the input digital signal with a stored non-linear normalization factor relating current to voltage in the lamps.

Abstract: A unit for detection and signalizing of functional defects for public lighting. A unit characterized by the fact that it comprises, for the one part, an emitter module (21) with which each street lamp is equipped, preferably located in its post, at the level of the junction box, the emitter module being equipped with a detector for current consumption (23) using the alternative network of the supply line as the carrier of a detection signal, and for the other part, of a receiver module (22) located in the supply cabinet of the same zone, this receiver module managed by a microprocessor which transmits a defect signal to the control room over a telephone line. This invention is of interest for manufacturers and installers of materials, equipment and components for public lighting.

Abstract: A warning system for burned-out condition of automotive lamps including brake lamps, high-mount lamps and tail lamps, includes a detection circuit for monitoring the lamps to produce a first signal indicative of the presence of a burned-out lamp, and for monitoring a brake-lamp switch and a light switch to produce a second signal when the brake-lamp switch is ON and a third signal when the light switch is ON. The warning system also includes a control unit which receives the first, second and third signals and determines the identity of the lamp group including at least one burned-out lamp, and an indicator which indicates the identity of the lamp group including at least one burned-out lamp on the basis of the determination by the control unit.

Abstract: A test circuit for testing all lamps in a system monitor for a hot water heater. The comparator includes a amplifier having a reference input connected to a reference voltage and a second control input connected to power through a plurality of different circuit elements in a voltage coupling network. A timer is connected in the circuit to the control input to provide a timed drive signal to a power switch unit connected to the comparator amplifier for energizing all of the lamps. The timer is a simple resistor-capacitor network with the comparator connected to the signal control input. The signal branch circuit includes components selectively inserted to produce a test signal to the timer and comparator amplifier. A thermostat monitor is connected by a diode to the comparator amplifier and a demand for hot water creates a turn-on signal to the comparator for the period of the timer to energize all lamps for a short period at the initiation of the demand.

Abstract: The present invention provides a Control Module 15 for controlling a dual filament bulb, in particular aircraft reading lamps, so as to detect the failure of one filament and energize the other filament. The Control Module 15 also has provisions for detection of bulbs that have only one or no operable filament(s) by activating an indicator (Light Emitting Diode) or connection to a test switch that will command the Module to activate bulbs that have two operable filaments only. The Control Module 15 consists of a solid state circuit made up of triacs, resistors, capacitor, diodes and fuse all packaged in a small printed circuit board. Interface between the Module and dual filament bulb, indicator or test switch is easily accomplished by a small connector on the Control Module 15.

Abstract: A protection system has a power supply connected to lamps by a low value resistor. The resistor is part of a voltage divider system which provides input signals to a number of comparators. These comparators provide appropriate signals to a microprocessor to indicate normal operation. When a malfunction is detected, the voltage drop across the low value resistor changes and alters the output of the comparators. The microprocessor thereafter produces an appropriate warning signal. In a vehicle turn signal circuit, the present invention is incorporated to detect a burned out bulb. A warning is provided to the vehicle operator when a bulb is out. Further, pursuant to federal safety regulations, the remaining functioning bulbs, when activated, flash at a substantially slower rate.

Abstract: In a series lamp circuit designed to connect lamps to the secondary windings of current transformers connected in series with a constant-current power supply, the series lamp circuit provides a disconnected lamp detecting means and a short-circuit switch for each lamp. The short-circuit switch serves to short-circuit the secondary windings of the transformers in response to the output of the detecting means. By actuating the short-circuit switch, the short-circuit switch is switched off during a short-circuit releasing time defined uniquely for a lamp at each predetermined inspection period. The power device side serves to detect the quantity of disconnected lamps on the basis of the output voltage and current and detect an OFF operating time of the short-circuit switch on the basis of an output voltage waveform of the power supply. Hence, it is possible to identify which lamp is disconnected and display the identified result on a display. An alarm is issued when the disconnected lamp is detected.

Abstract: A self-relamping clearance/marker light assembly includes a pair of lamps connected to a proving ring switch. A primary one of the almps is lighted and the switch prevents current flow through a secondary one of the lamps until the primary lamp burns out. The lamps are operated at a derated voltage to increase life and a small compensating lamp provides the necessary additional illumination lost through the reduced voltage operation of the primary and secondary lamps. The lamps are mounted for isolation from high frequency vibration and shock impacts using the lamp lead wires to form part of the shock mounting.

Abstract: A control unit for verifying the functionality of the pilot lamps installed on the instrument board of an automotive vehicle is proposed, wherein a central control unit continuously monitors the functional condition of the devices monitored by the pilot lamps and wherein by means of hand-operated actuation device, the functionality of the pilot lamps can be verified also while the car is running.

Abstract: A turn signal control circuit has a power source, left and right turn signal inputs, a speed detection input and circuitry for conditioning the power source voltage and current as well as the input signals for proper operation. When a turn signal switch provides an input signal to a logic controller, the circuit begins flashing the respective turn signal. Upon release of the switch, a microprocessor reviews the vehicle speed by way of a speedometer input line and references a lookup table to determine the proper distance at which to turn off the signal. Generally, the faster the vehicle is travelling, the longer the turn signals are left on. Various manual cancellation options are also available to the motorcycle operator. A four-way flasher sysem is operated by simultaneously pushing the two turn signal switches, remaining on until both switches are again simultaneously pressed.

Abstract: A method for continuously and automatically monitoring the electrical operability and control reliability in a liquid crystal display unit and comprising, inter alia, determining the discharge or charge time of a capacitor comprised of a segment and the backplate or return electrode of the display unit when a voltage waveform fed to the segment has been disconnected, said time being determined by a binary counter which commences at the moment of disconnection of the feed waveform and stops when the capacitive discharge or charge waveform differs in binary state from the value of the segment feed wave.

Abstract: A three-condition constantly illuminated status indicator is provided in a circuit breaker to provide three luminesce displays indicating that the breaker is in the on, off or tripped condition. Associated electrical circuitry employs diode-steered capacitive charging elements for selective, common or simultaneous energization of a three-color light emitting diode display without acting as a bypass around the circuit breaker, thus eliminating shock hazard. Selective energization of the light emitting elements is achieved by auxiliary switching means operable to a plurality of switching conditions according to switching conditions of the circuit breaker. The capacitors serve as an impedance to current for the light emitting diodes, eliminating the need for ballasting resistors, resulting in a cooler operating, lower power consumption unit.

Abstract: A system for failure detection of series-fed lighting circuits monitors the status of series-fed lamps and provides for feedthrough shift circuit protection of the isolating transformer and for suppression of overvoltage which appears at the failed lamp terminals. Current monitoring systems are rendered obsolete by this RLW (Runway Lighting Warning). The RLW system, which consists basically of a control unit equipped with detector probes, utilizes the series-fed lamp supply line, without any need for supplementary lines, and displays the failed lamp identification number accurately. The system has its preferred application in series-fed support lighting systems, but may also find application within any series-fed lighting system such as that of harbors, road networks and so on.

Abstract: A terminal block assembly comprising terminals in combination with associated signal indicators is disclosed. The assembly includes one or more rows of terminals and, associated with each row of terminals, a row of signal indicators. The signal indicator typically is a light emitting diode. Each indicator is located in proximity to one or a few terminals, to which it may be connected electrically. Each signal indicator displays the operational status of a load module connected to a terminal on the terminal block assembly. Operational status may include fault detection, output signal, input signalling, or the like. The placement of the signal indicator immediately adjacent to its respective terminal simplifies and speeds up identification and eliminates any question of improper identification of the load modules connected to the terminal blocks.

Abstract: A diagnostic meter base, used for testing the connections of a self-contained meter in a polyphase installation is described. The diagnostic meter base comprises a box-like casing, one end of which defines a socket with contacts to engage respective contacts of the meter, and the other end of which defines a plug with contacts to engage respective contacts of a permanent support socket of the installation. The casing houses a network of circuit elements each including a lamp which responds to current through the element, whereby the pattern of lamp responses is indicative of the pattern connections in the installation. The lamp bulbs are mounted in a well at one end of the casing, the well having a hinged cover.

Abstract: A flasher device flashes a selected one of a plurality of groups of indicator lamps selected by a flasher starting switch. An intermittent voltage is supplied to the selected group of indicator lamps to cause the lamps to flash. A capacitor is operatively connected to the selected group of indicator lamps and the rate of change of the voltage across the capacitor is indicative of the resistance of the selected group of indicator lamps. The frequency of the intermittent voltage supplied to the indicator lamps to flash the lamps is varied in response to the rate of change of the voltage across the capacitor. As the rate of change of voltage across the capacitor varies in relationship to the resistance of the selected group of indicator lamps, the change in the frequency of the intermittent voltage supplied the indicator lamps and thus the flash rate of the indicator lamps is representative of the resistance of the group of lamps.

Abstract: A surgical microscope apparatus provided with a failure detecting device for conducting an initial examination and an ordinary examination of an illumination device and a failure detecting device for conducting the ordinary examination of an electric magnification and focusing device, in order to make it possible to self-examine what is defective and indicate the result when failure is caused. The failure of the illumination device is immediately indicated by the self examination of the failure detecting device when a power source is turned on for use.

Abstract: A switching system for powering first and second electrical loads from a voltage supply, the electrical loads being operable from controls and adapted to be connected to the voltage supply by the switching system. The switching system includes switching circuitry having a control element which is responsive to a control voltage difference to cause the switching circuitry to become conductive, the switching circuitry having a switch terminal connected to a first supply line and another switch terminal connected to the first electrical load. The switching system also includes additional circuitry responsive to the controls for generating the control voltage difference when the voltage supply is connected to the first supply line thereby powering the first electrical load from the first supply line. The switching system further includes further circuitry responsive to the controls for generating first and second control signals.

Abstract: To check the signals of the electrodes of a 7-segment display, the device comprises a multiplexing assembly, a detector of the level of the signals, a generator of clock signals of different frequencies, a pulse counter, and an anomaly detector.

Abstract: A monitor circuit arrangement for traffic lights wherein energy is supplied from an alternating voltage supply source(s) to a lamp (L 1) via a controlled switch (SD 1) and energization of the unit is monitored by a voltage comparator connected in cascade with a sensing latch (SL 1). The output of the voltage comparator is activated in response to its input voltage exceeding a predetermined magnitude of either polarity relative to a common reference voltage wave. A monitored voltage representative of the voltage present across the lamp is supplied as an input voltage to the voltage comparator, the output of which is fed to the sensing latch set input. Reset means (RPS) are provided for resetting the latch at the commencement of each cycle of the alternating supply voltage.

Abstract: A facility for monitoring the operation of a signal lamp in the outdoor installation of an interlocking. Such signal lamps are powered through lamp transformers located in the immediate vicinity of the lamps. Monitoring for filament breaks is done on the primary side in the interlocking station. The monitoring poses problems in the case of great control distances because leading reactive currents occur on long leads. The invention uses a modulator in the secondary circuit of the lamp transformer which impresses on the lamp current a unique modulation pattern that is recognized in the interlocking station. In addition, the modulator may be turned on via a photocell responsive to the light of the signal lamp, and may perform additional control functions, such as turning on auxiliary light sources.

Abstract: A failure compensation circuit automatically reduces the output voltage of a power supply when a portion of a load drops out. The compensation circuit includes a circuit for generating a control signal representative of the desired voltage across the load. A power supply supplies voltage to the load in response to the control signal. An input signal representative of the current delivered to the load is produced which decreases whenever a portion of the load drops out. The circuit for generating the control signal is responsive to the input signal for adjusting the control signal such that when the current delivered to the load decreases, the voltage delivered to the load is automatically reduced.

Abstract: The process and the device enable the electrical powering of a circuit having a conductor (1) with high thermal inertia by means of a transistor (3) with low thermal inertia. According to the invention, the device comprises a current limiter circuit (4,5,7,11), a voltage detector circuit (8) and a control microprocessor (6) which, according to a pre-established program, controls the flowing and stoppage of current in the power transistor (3) controlling the powering of the conductor (1) with high thermal inertia.Application to the control of lights in automobile vehicles.

Abstract: A system for feeding and controlling low intensity obstruction lights, involving low power drain especially in radio stations powered by solar cells includes:a sub-system which not only generates the energy necessary to feed the obstruction light, but also detects solar intensity;a control sub-system which delivers energy to the obstruction lights, triggered in correspondence to a light threshold, generates indicator signals on the operating state of the main on/off switch and the power circuit breaker and generates a lamp failure control for telemetering purposes and fault controls for the individual obstruction lights for local displaying purposes; and a low luminous intensity and low power drain lighting sub-system.

Abstract: A lamp failure detecting device for automobile consists of a lamp circuit including a plurality of lamps connected in parallel, a current-detecting resistance connected to a power-supply source through the lamp circuit in series, a first voltage divider circuit including resistances to which a voltage divided by the current detecting resistance and the lamp circuit is applied a second voltage divider circuit including resistances to which a voltage supplied from the power-supply source is applied and a comparator circuit comparing the difference between the divided voltages in the voltage divider circuits to produce a a failure detection signal. Diodes are provided in the first and second voltage divider circuits respectively in the forward direction. Non-linearity of the current flowing through the lamps for the change of the power-supply voltage is corrected by the diodes.

Abstract: An apparatus and method are disclosed which find particular utility as a component of a traffic control system known as a conflict monitor. The apparatus includes a number of solid state switches which are activated to scan inputs from traffic control signals. The inputs are sequentially applied to a A-D converter which samples the voltage and applies it to a microprocessor which is programmed to determine the voltage and analyze the signals for conflicts, or other errors. The input lines are also connected to terminals of a program board whereby the microprocessor can instruct a switch to ground the common pin on the program board to allow program board inputs to be applied to the microprocessor for indicating permissible conflicts. A method includes a technique for determining the voltage of an input analog signal by scanning a plurality of input signals and sampling them in accordance with a relationship which provides minimum error. A display may be operated in one of two modes.

Abstract: A filament bypass circuit for use with a string of lamps in series capable of continuing current flow when a lamp in the string fails. Each lamp is provided with a shunt circuit consisting of a series circuit of a diode and a silicon bilateral voltage triggered switch. The switch becomes conductive upon the application of a substantial increase in voltage from the A.C. source and remains conductive until there is an interruption of current flow or current flow drops below its required holding value. The diode insures that during continued operation after a failure there will not be an excessive voltage applied to the remaining lamps, and also serves as an indicator of a failed lamp.

Abstract: A vehicle light control system for controlling the low beam of headlights of a vehicle. The system comprises a first and a second switching device with the first switching device being in a normally conductive state and the second device being in a normally non-conductive state. The first switching device is connected to the alternator of a vehicle to tap a supply voltage therefrom. The second conductive device is condition by the first conductive device and is also connected to a supply voltage to feed the low beams of the headlights when conditioned to do so by the first switching device. The headlight switch of the vehicle when switched on the high beams cuts off the first switching device and the supply voltage to the low beams. The supply voltage fed to the low beams is further reduced whereby not to subject the low beams to full intensity whereby to prolong their life span.

Abstract: An apparatus for detecting, for example, the disconnection of signal lights such as flashers for vehicles and for warning of this disconnection has a detecting resistor element for converting an ON current of the signal lights into a voltage signal. The voltage signal detected by this resistor element is compared with a reference voltage which is set at a discrimination/oscillation control circuit so as to detect if the detecting voltage signal is lower than the reference voltage. When such a state is detected, the oscillation frequency of an oscillator for changing the flashing frequency of the signal light is doubled. The disconnection of the lights can be detected by observing the frequency of the flashing signal. The detecting resistor element consists of a resistive wiring formed of a resistive material which is processed so as to have a smaller resistance than desired.

Abstract: An automobile circuit tester is provided having an end connection receivable in the taillight socket, parking light socket, brake light socket or directional signal socket in place of the bulb. When a circuit is completed to the socket in which the tester is received, an audible signal is generated.

Abstract: A monitoring device for use with a loop circuit including a plurality of lights, which includes a monitoring current transformer having a magnetic core with a primary circuit connected in series with the loop and a secondary circuit coupled to the primary circuit, the primary circuit being arranged such that the loop current saturates the transformer core and the secondary circuit being in open-circuit condition, the monitoring current transformer generating a monitoring voltage signal in response to each inversion of the loop current. The monitoring voltage signal is used to generate a window signal during the time interval when the monitoring voltage signal has a significant value and the window signal is then used to control the integration of a signal representative of the loop voltage with a view to producing a detecting signal which is indicative of the number of defective lights. The integration time interval is thereby determined whatever the loop current waveform may be.

Abstract: An optical indicator apparatus includes an optical output device for producing a light output in response to an electrical input thereto, a hollow housing for supporting the optical output device relative to another device to permit viewing of light output by the optical output device, electrical input leads extending through at least a portion of the housing for receiving such electrical input and coupling the same to cause the optical output device to produce an output indicating receipt of such electrical input, and seal material for sealing in substantially fluid-tight relation in the hollow housing at least part of the optical output device and at least part of the electrical input leads while holding the same in relatively fixed position in the hollow housing.

Abstract: The invention relates to a circuit for indicating faults in a current consuming load connected to an electronic switching device by means of an indicator device wherein the input of the electronic switching device receives a signal via a control line to cause the load to be switched on. The problem of reducing the number of lines leading to a central operating location is solved in that the input resistance of the electronic switching device is made to be variable by means of an impedance which is controlled by an error signal and the indicator device is actuated in dependence on the current flowing in the control line and emits a fault indication if the current in the control line deviates from the value which it has when there is no fault.

Abstract: A microcomputer controlled monitoring system and method for detecting an electrical open, shorted or operative condition of an electrical load. A load switch circuit couples the load to a common voltage line and is controlled by a single drive line from a microcomputer controlled load monitor circuit.

Abstract: The top, flashing lights and steady-burning side lights placed on an elevated obstruction to warn aircraft are monitored by a failure-detecting circuit. The circuit includes circuit components which detect and indicate the failure of either or both top lights, the latter case possibly indicating the alternative of continuous operation thereof, and for detecting and indicating one or more failures of the side lights. Provision is made for remotely actuating an internal latching relay which so changes internal connections that all detecting and indicating components should response.

Abstract: A flasher unit is provided with a comparator whose output signal is fed to a pulse generator for producing the flash frequency signal, the comparator being supplied with a reference voltage at one input and a voltage dependent on the current passing through the flasher lamps at the other input and with a switch element which changes the reference voltage in accordance with the comparator output signal such that the comparator produces an output signal for the whole of the light up time of the lamps.

Abstract: A sensing and indicator system for monitoring multiple electric heating elements connected in three-phase balanced Y circuits in heat reactivatable adsorbent gas fractionators. The system senses a failure induced imbalance, pinpoints the location of the group with the failure and causes a failure indicating alarm to function. The system operates by a sensing circuit including a discharge bulb sensing the failure induced imbalance and causing a conduction of current through the system resulting in the activation of an alarm and the illumination of the gas discharge bulb indicating which of multiple sets of heating elements has failed.

Abstract: Traffic signals at an intersection are controlled by one or more controllers of the state/interval type, located in the vicinity of the intersection. One or more remote units that are portable or mobile communicate with the controller via a coded signal to command specific light operations, instruct a secondary controller to take-over light control at the intersection from a primary controller, and to reprogram the operation of the controller on a temporary or permanent basis. The remote units generate a code that must be received accurately by the controller before commands are followed. In order to economically provide such a code, the code generator employs a diode matrix that orders data words and address words and is easily reprogrammed. The traffic signal indicator operation is monitored by the controller both to detect controller error, as by a voltage error resulting from an incorrect controller action, and to detect a non-controller error, as by a current error resulting from a burned out indicator.

Abstract: The invention relates to a device for checking a plurality of indicator lights, wherein the intensity passing through each indicator light is sequentially measured and the measurements are compared with nominal intensities. The invention is more particularly applicable to the checking of the indicator lights of devices monitoring functional members.

Abstract: A runway approach lighting system with fault monitor includes an oscillator which develops clock pulses which are accumulated by a counter. The output of the counter is used to develop trigger signals which control the sequential energization of runway alignment indicator lights. The operation of each light is sensed and is compared with the oscillator pulses, and a fault signal is generated each time a light fails to operate in response to a trigger signal. The number of fault signals generated in an energization cycle is accumulated, and a fault indication is generated once a predetermined number of faults has occurred.

Abstract: In a portable traffic control system in which receivers are controlled from a central transmitter the carrier signal employed is modulated by two different modulation signals in order to command a green light to be shown, reducing the possibility of this happening accidentally. The receipt of a carrier signal with only a single pilot modulation causes production of a red signal. An amber caution light if present is lit automatically upon turning off green, and flashing amber is produced by switching on green and then turning it off before the green can be lit. A drop in battery voltage below a predetermined level will cause a flashing red signal to warn and conserve the battery power. A non-resettable link in circuit with the green light is broken upon existence of a malfunction condition whereby another light is lit while green is alight, so that the green can no longer be lit until the unit is serviced to remove the malfunction.

Abstract: A lamp circuit is provided having a constant current-type AC power source and a plurality of isolation transformers coupled in series with the AC power source. The secondary circuit of each isolation transformer is connected to an electric lamp. The output voltage of the constant current-type AC power source is detected to determine the times when the output voltage crosses the zero voltage level. A disconnected lamp in the circuit results in a distortion of the output voltage waveform due to the magnetic-saturation characteristics of the isolation transformer coupled to the disconnected lamp. The output voltage waveform is integrated over time between the time periods when the output voltage signal crosses the zero axis. The result of the integration is compared with a reference value. When the integrated value exceeds the reference value, an alarm signal is generated. The number of disconnected lamps may also be determined and displayed.