Abstract: In a power window device, a DOWN switch has first and second switches in a power window circuit located in a door for a window of a passenger's seat. A normally-closed contact of the first switch and a remote UP terminal of the power window circuit to which an UP signal is applied from a power window circuit provided near the driver's seat are connected. A normally-closed contact of the second switch and a remote DOWN terminal of the power window circuit to which a DOWN signal is applied from the power window circuit are connected. When the DOWN switch is manually operated, a signal supply line to which the UP signal and the DOWN signal are applied and a power supply line to which a power source is connected are electrically disconnected. As a result, the power window device is operable even when the signal supply line is grounded due to submerging in water.

Abstract: The invention comprises a programmable emergency-stop circuit apparatus and method that provides advanced functions not found in other systems. The circuit centralizes the control of high voltage motor power into one place, by providing connections for, in its minimum configuration, several different kill switches, a motors-on button, and an AC motor power relay coil. In the present invention, kill switches, emergency-stop and motors-on buttons, computer ready and watchdog signals are all conveniently connected in one location, alongside the AC motor power relay coil driver.

Abstract: A quick stop circuit for a spring applied quick stop mechanism coupled to an electrically operated actuator includes a dual quick stop switch which includes a simultaneously operated normally open switch and a normally closed switch. The closing of the normally open switch causes control units to turn off a relay which controls energizing of the actuator through an actuator relay. The opening of the normally closed switch de-energizes a quick stop relay which disconnects the driver from its power source, which also de-energizes the actuator relay, which de-energizes the actuator so that the spring applied quick stop mechanism will move to its stop position.

Abstract: A method for starting an electromechanical regulating device especially designed for controlling the charge cycle in an internal combustion engine. The electromechanical regulating device has an actuating element and an actuating drive. The actuating drive includes a first electromagnet with a first coil and a second electromagnet with a second coil, an armature which can move between contact faces of the first and second electromagnets, and at least one restoring means which is mechanically coupled to the armature. To start the regulating device, the second coil is energized until a first predefined condition is fulfilled and then the first coil is energized from the time at which a second condition is fulfilled until the armature comes into contact with the contact face.

Abstract: A method of programming one or more relay based electrical devices comprises the steps of selecting an electrical device to program, switching the relay from a first state to a second state, and applying a time varying signal to the relay associated with the selected device. The method also includes the steps of counting signal transitions occurring during the switching of the relay, and comparing the counted signal transitions to a predetermined value. The method further includes the step of programming the device based on the comparison step. Accordingly, the programming methodology advantageously enables programming of the device by employing the switching time period of the relay which allows for elimination of a separate dedicated programming terminal.

Abstract: An actuating device for a motor used in a power window of an automobile which can drive the motor reliably to open the window even when the automobile is submerged in water. This device has a simple configuration is relatively small and inexpensive. This activating device comprises a drive circuit for a motor which has first and second relays to allow electric current to flow so as to drive the motor in either the forward or reverse direction. The contact of the second relay, which drives the motor in one direction, is used in such a way that the contact forms a part of an electronic circuit for the magnetic coil of the first relay. When the second relay operates, the electric circuit for the magnetic coil of the first relay is closed off. This activating device can ensure that a power window will be opened even if the automobile is submerged, and the first and second relay are switched ON at the same time.

Abstract: The control device comprises a piloting circuit for the electroactuators and a timing circuit which generates timing signals supplied to the piloting circuit for control of the electroactuators. The piloting circuit has a first and a second input terminal which are connected in use respectively to a first and a second terminal of an electrical energy source, and a plurality of pairs of output terminals, one for each electroactuator; each pair of output terminals comprising a first and a second output terminal, between which a respective electroactuator is connected in use. The piloting circuit comprises a plurality of control circuits, one for each electroactuator, which receive as input the timing signals and are activated selectively by the timing signals themselves.

Abstract: A sequential controller is provided for sequencing multiple electric loads such electric pumps. That is, for each cycle the next load is designated as the lead load in a round-robin fashion. The controller uses cost effective electro-mechanical relay logic an thus avoids conventional solid state technology. In order to sequence the loads on each successive cycle, the electro-mechanical relay connected to the sensors comprises a double-throw contact set. The double-throw contact set comprises two complementary contacts, both of which alternate between normally open and normally closed on each successive cycle. In this manner one each successive cycle, the pumps designated as the lead pump and the lag pump automatically alternate in a round-robin fashion. Further, when the lead pump is disabled the lag pump is immediately actuated without disruption of service.

Abstract: A control circuit array for controlling operation of a plurality of multi-product fuel dispensers ("MPDs") in response to control inputs from a control input source. The control circuit array includes an electric power source, switches for fuel grade selection and MPD lighting and outputs to submersible turbine fuel pumps for supplying fuel to the MPDs. The improvement comprises a modular circuit board for being connected in series to form the control circuit array, wherein each circuit board includes emergency shutoff means for responding to a single emergency shutoff input for shutting off all power to each of the plurality of MPDs and the turbine pumps supplying the MPDs.

Abstract: A feed line connecting circuit for selectively connecting first, second and third feed line connecting terminals under a predetermined current feeding condition comprises a first current detector connected between one of the first and second feed line connecting terminals and a central node for detecting a current over a predetermined value; a first switch connected between the one of the first and second feed line connecting terminals and the central node for connecting said one of the first and second feed line connecting terminals to the central node under an unpowered condition; a selective switch controlled by the first current detector, the selective switch having first and second contacts and a common contact connected to the third feed line connecting terminal, the common contact being connected to the first selective contact when the first current detector does not detect a current over the predetermined value, and to the second selective contact when the first current detector detects a current over

Abstract: An apparatus for independent voltage, air pressure, and/or fluid pressure control of multiple material or coating applicators, such as paint spray guns, includes a multiple gun control board that allows a single power supply to provide voltage to a plurality of paint guns and an independent gun control board that can output a different voltage signal for each gun to generate different gun operating voltages, different air pressures, and/or different fluid pressures. The independent gun control board includes a separate relay and potentiometer for each gun to be controlled. The potentiometer is adjustable so that the output voltage of the independent gun control board can be varied. The output voltage can be used to control the paint spray gun operating voltage and/or be sent to a pressure transducer to adjust the air and/or fluid pressure at which the triggered gun operates.

Abstract: Control circuit for electromagnet with two coils used to determine a call phase and a hold phase, and powered from a DC power source. The energy source comprises a current generator and a capacitor powered by this current generator. A control device controls two switches, in which the first switch controls discharge of the capacitor in the first coil during the call phase, and the second switch sets up current passing through a second coil during the call phase and the hold phase. The required current output from the current generator is thus reduced.

Abstract: A system and method for controlling relays. The method may comprise receiving one or more input commands for a plurality of relays, with the plurality of relays including a first relay, and a last relay, initiating actuation of the first relay after receiving the input relay commands, and initiating actuation of the last relay after initiating actuation of the first relay. Initiating actuation of the last relay does not wait for a debounce of the first relay. The method waits a debounce period after initiating actuation of the last relay. The debounce period operates to debounce the last relay and the first relay. One or more second relays may also be included in the debounce sequence. The relays may be latching or non-latching relays. The method may determine if another relay is required to be actuated after initiating actuation of each relay. One of the input commands may include a debounce mode input. A delayed debounce mode debounces the plurality of relays only after the last relay has been actuated.

Abstract: A driver circuit having logic circuitry which controls the coil and assoced contacts of a four pole double throw relay. The four pole double throw relay is toggled such that a large latching current flows through a first of a pair of solenoid coils of the magnetic-latching solenoid, while a relatively small current flows in the second solenoid coil of the magnetic latching solenoid in an opposite direction. Toggling the relay's coil causes the latching current to now flow through the second solenoid coil of the valve, while the relatively small current flows in the first solenoid coil of the magnetic latching solenoid again in the opposite direction.

Abstract: A switching multiplexor arrangement of relays having configuration flexibility and operative for balancing thermal offset of the relays Accumulated thermal offset of the relays along the various propagation paths through the multiplexor is balanced, by maintaining equal numbers of configured relays, along the various propagation paths, so that there are substantially equal amounts of accumulated thermal offset for the various propagation paths.

Abstract: An automobile electrical circuit including a battery, turn signal switch, flashers, parking light switch, brake switch, relays, and front and rear lights. In the daytime or at night, the high filaments flash when the turn signal on that side is activated. At night, the low filaments flash synchronously with the high filaments when the turn signal on that side is activated.

Abstract: Pulsed-energy controllers and methods of operation thereof for driving inductive loads such as the actuator coil or coils of electromechanical actuators. The controllers utilize an inductor through which an initial current is established through a first circuit. The inductor is then switched across the actuator coil or other inductive load in a second circuit and the first circuit is opened. The back EMF of the inductor, limited by a high voltage protective device, causes a rapid rise in the current through the actuator coil, the rise being much faster than could be achieved by merely coupling the supply voltage, as used to establish the current in the inductor, directly to the actuator coil. By proper selection of the controller circuit and its parameters, the initial rapid current rise may continue to a current higher than a steady state current, after which the current will decrease to or toward the lower steady state current until the current pulse is terminated. Various embodiments are disclosed.

Abstract: A solenoid driver circuit adapted for use with a digital magnetic latching olenoid which has first and second solenoid coils. The solenoid driver circuit includes a bridge circuit which receives a logic signal and first and second pulse signals. The solenoid driver circuit also includes a voltage source which provides a direct current and first and second resistors respectively connected to the first and second solenoid coils. The bridge circuit, responsive to the logic signal and the first pulse signal, provides a first current path from the voltage source through the first solenoid coil and the first resistor to ground and a second current path from the direct current voltage source through the second solenoid coil to ground.

Abstract: A system for controlling the connection of power from a main supply (11) to electrical devices (22) by way of switching devices (19). The system includes a low voltage, direct current power supply (10), a plurality of command units (15) connected to and powered from the power supply by way of an electrical connection (14), and a plurality of switching devices (19) connected to and powered from the power supply by way of the electrical connection (14). Each of the command units (15A, 15B and 15C) is arranged to generate a uniquely coded pulse-form command signal to a central processing unit (18) by way of the electrical connection (14), and the central processing unit is arranged to generate pulse-form actuating signals having codes determined by the command signals. The central processing unit is arranged to feed the actuating signals to the switching devices (19) by way of the electrical connection (14).

Abstract: A method is described for operating a relay arrangement having a magnetic circuit comprising two excitation core each arranged on a core, a yoke and an unstably mounted armature, two contact springs that can be operated by the unstably mounted armature, two make contacts, two changeover contacts and a common break contact. In the normal state of the relay arrangement, the two changeover contacts are connected to the common break contact and when the response threshold of the relay arrangement is reached one of the two changeover contacts is connected to the corresponding make contact. The magnetic circuit is excited electromagnetically in the normal state of the relay arrangement in order to generate a normal-state armature force that acts on the unstably mounted armature.

Abstract: A switching circuit for use in a subterranean probe for switching between to two modes of operation used to perform a survey of a well borehole. The switching circuit comprises a first voltage bias network which is biased to a predetermined overvoltage criterion; a second voltage bias network which is biased to a predetermined negative voltage criterion; a switch; and a negative voltage blocking diode for blocking the predetermined negative voltage criterion for allowing the first voltage bias network to fully realize the negative voltage criterion.

Abstract: A circuitry for detecting a fault current or leakage current on the supply line of an electronic circuit includes a current source which is rated for a maximum allowed fault current or leakage current. The current source is fed by an auxiliary voltage source. The potential on the supply line which prevails when the supply voltage is disconnected due to the leakage current is determined and assessed by a potential monitor.

Abstract: An alternator circuit for alternately operating one of first and second electrical load devices which uses a magnetic latch relay to perform the alternation. The circuit includes a first circuit means for supplying electrical energy from a source to one of said first and second electrical load devices, and magnetic latch relay alternating means having first and second states. The alternating means in a first state interconnects the first electrical load device to the first circuit means, and in the second state interconnects the second electrical load device to the first circuit means. One application of the inventive circuit is for use in controlling the level of liquid in a container within a predetermined range using 2 pumps.

Abstract: A circuit arrangement for independently switching the induction coils of several d.c.-operated solenoid valves connected in parallel that, with a reduction of power loss, features a disconnection time which is independent of the voltage of the d.c. voltage source.

Abstract: A solenoid valve driving device includes a bypassing current path of which one end is connected to a point between a first switching device and a first solenoid valve and another end is connected to a point between a second switching device and a second solenoid valve, and an element disposed in the bypassing current path and having a characteristic that causes current to flow from the first switching device side to a second switching device side. By adopting the above described constitution, through current generated when the first switching device is switched from an OFF-state to an ON-state during duty control of the first switching device can be suppressed by the inductance of the second solenoid valve. In this way, one solenoid valve among a pair of the first and second solenoid valves, which is not operated, has a function of suppressing the through current.

Abstract: An arrangement for driving actuator coils for two or more driven devices employs a microprocessor or similar controller and an actuator driver circuit. The actuator driver circuit controls two or more relay actuator coils from a single microprocessor output terminal. This output terminal can provide a high, low, or pulse output signal. An amplifier switching device, such as a transistor, whose base is coupled to the output terminal of the microprocessor, drives the first relay actuator coil as its load. A rectifying diode is connected to one end of a capacitor and thence through a negative resistance device to a second relay actuator coil or other driven device. The coil impedances are selected so that the second coil has a significantly higher impedance than the first coil. When output pulses appear at the microprocessor output terminal, the transistor switch pulses on and off, and thus energizes the first coil.

Abstract: A safety-related control system (SRCS) designed to safeguard personnel operating hazardous production equipment. The SRCS integrates the safety-related part of a machine into one homogenous system for the purpose of increasing safety. In so doing, the SRCS monitors the machine, the operator, and itself for safe operation. The SRCS utilizes a non-material barrier to sense the intrusion of a person's body into a hazardous area of a machine. The SRCS uses machine feedback and/or operator interface to determine whether a hazardous condition is present. If such condition is present, the hazard is rendered harmless by the time the intruding body member can reach the potential danger area. The system includes separable means for stopping motion of the moving parts of the equipment, starting movement of the movable parts, and detecting faults in sections of the system.

Abstract: The control device has a drive circuit, in turn having a number of modular circuits--one for each inductor--activated selectively and receiving timing signals, and a common circuit connected to the modular circuits and cooperating with the activated modular circuit to supply the respective inductor. Each modular circuit has a first controlled switch connected between a first input terminal and a respective first output terminal, and a second controlled switch connected between the respective first output terminal and a storage capacitor; and the common circuit has a third controlled switch connected between the storage capacitor and a respective second output terminal, and cooperating with the second controlled switch to selectively transfer energy between the storage capacitor and the respective inductor.

Abstract: A circuit isolator apparatus for use with pump or master valve circuits having a plurality of controllers connected thereto. One isolator apparatus is used in association with each controller. The isolator apparatus includes a pair of relays which allow only one controller to access the pump or valve circuit at a time to prevent feedback between controllers and damage to controllers due to incorrect phasing.

Abstract: The present invention provides a circuit breaker control arrangement that is reliable, accurate and cost-effective to manufacture, install and maintain. This circuit breaker arrangement also provides increased modularity by alleviating the need for installing wires to connect each circuit breaker with the control station. The present invention uses circuit breakers that contain internal control technology for interrupting and establishing an associated current path. At least one coded signal designates each circuit breaker, and a communication bus carries these coded signals to each circuit breaker. Decoding technology located on each circuit breaker determines whether the coded signal corresponds to that circuit breaker. If the coded signal does correspond to that circuit breaker, then the decoding technology responds by sending the appropriate response signal over the communication bus, and the circuit breaker's internal control technology either interrupts or establishes the associated current path.

Abstract: A relay control circuit is provided to perform on/off control on multiple kinds of relays, each having a different operation speed, which are contained in a source-voltage supply circuit which is employed by an IC tester to perform DC-parameter measurement on ICs. The relay control circuit contains a timer-A and a timer-B, to which different relay-operation wait times are arbitrarily set, wherein the timer-A is set in response to a relay whose operation speed is slowest within the multiple kinds of relays. When a test instruction is executed in accordance with a test program, relay-select-information, representing at least one of the multiple kinds of relays, is generated. A relay-operation monitoring circuit, contained in the relay control circuit, monitors a driving relay by detecting coincidence between current relay-select-information, regarding a current test, and previous relay-select-information regarding a previous test.

Abstract: A low voltage power inverter utilizes reed switches to control a number of display tubes. The reed switches are controlled by magnetic coils or permanent magnets. The magnetic coils receive a control signal from a control circuit. The control circuit is powered by a capacitor coupled around a power lead and a capacitor coupled around a return lead. The permanent magnet is coupled to a mechanical actuator.

Abstract: When a trouble occurs in a cable, a feeding pass for another cable is ensured. In a feeding pass switching circuit, optical fibers are respectively connected to the terminals A, B and C. When a negative current is applied to the system in a state where a BRANCH2 is put in an open circuit and a TRUNK is grounded, a relay K1 is activated, and then a relay K2 is activated. Successively, when a positive current is supplied from the TRUNK, a cable connected to the TRUNK and a BRANCH1 is fed from both terminals. When the positive current is supplied from the BRANCH1 in a state where the TRUNK is put in a open circuit and the BRANCH2 is grounded, a relay K3 is activated. Successively, when the negative current is supplied to the BRANCH2, a relay K5 is activated. In such a manner, the power is fed to each feeding pass from one terminal.

Abstract: The control path of the switch (I) comprises an input stage (T2, T1) having an input (H) coupled to the input (E) for the control signal and having its output coupled to the control electrode (G) of the switch (I). A protection circuit (D1, Z2) coupled between the load (C) and the control path includes a threshold effect component (Z2) and a decoupling element (D1). On being made conductive by the current that results from a surge generated in a circuit of the load (C), the protection circuit (D1, Z2) is coupled to the input (H) of said input stage (T2, T1) to act on said switch (I) in the same way as a control signal for the switch (I). In this manner, the control path prevents current in the load (C) from dropping off suddenly.

Abstract: A control cabinet for distributing power to a plurality of automated independent and parallel operated loads. A plurality of control cabinets can be interfaced with control cable to be supervised by one main controller. The main controller distributes low voltage ac signals to each control cabinet, which transfers the low voltage signal into high voltage power distribution by a series of low and high voltage relays, thus eliminating the need for excess circuit boards and transformers normally associated with this task.

Abstract: The invention is a dishwasher and a control therefore in which the control comprises multiple parallel loads, including a motor. The motor and the other loads are connected to one side of a power source by a motor relay, which is controlled by a processor. All the loads, except the motor, are connected to the other side of a power source by semiconductor switches with each load having a corresponding switch. The motor has an unswitched connection to the other side of the power source. The power to all the loads, including the motor, is controlled by the motor relay. If one of the switches fails in such a way that the circuit for one of the loads is closed, then the load will be shut off when the motor relay is opened to shut off power to the motor. Thus, it is possible to prevent the failed load circuit from operating during the entire wash cycle.

Abstract: A motor control assembly and method of controlling a motor includes a three phase variable reluctance motor. Each phase includes two separate coils driven by separate driver circuits under the control of a microcomputer. The microcomputer monitors feedback from each driver circuit to determine faults or errors in the driver circuits or respective coils. In the case of a fault detection, one of the driver circuits and coils for each phase may be disabled to allow continued operation of the motor with the remaining driver circuits and coils.

Abstract: A pulse-width modulation control system having a power source, driver circuits connected to the power source, and two solenoids, such as those for a vehicle automatic transmission, connected to the power source through the driver circuits, and pulse trains of a predetermined PWM duty ratio are supplied. The supplied currents are detected and A-D converted. In the system, one pulse train lags behind the other at the leading edge. When PWM controls two solenoids at the same time using an on-board microcomputer, two voltage memory circuits are additionally needed, since the microcomputer ordinarily has only one A-D converter. With the arrangement, only one voltage memory circuit is needed, rendering the system configuration simple.

Abstract: An isolation system for allowing a single measurement circuit to measure both low and high voltage signals from separate low and high voltage buses, respectively, while maintaining substantial isolation protection for humans or animals potentially exposed to the low voltage bus. A central relay coupled to the measurement circuit selects between the low and high voltage buses and thus provide one level of isolation. Two mutually exclusive relays on either side of the central relay provide another level of isolation. Since the central and the two mutually exclusive relay are all rated at the basic insulation level, the low and high voltage buses are separated by at least two relay levels thereby meeting the double insulation or high voltage testing standard during normal operation. For additional protection, should one or more of the relays fail, dual spark gaps limit the maximum voltage to an intermediate voltage level.

Abstract: A method of controlling movements of an armature in an electromagnetic circuit which includes at least one holding solenoid applying magnetic forces to the armature and at least one resetting arrangement for applying a resetting force to the armature. The method includes the following cyclical steps: switching on a holding current to flow through the solenoid for holding the armature at the solenoid; after a predetermined period, switching off the holding current for causing the armature to begin a motion away from the solenoid; after switch-off of the holding current detecting, across the solenoid, a voltage change caused by the displacement of the armature for recognizing a starting moment of armature motion from the solenoid; and deriving a control signal from signals representing the voltage change ascertained in the course of the detecting step.

Abstract: A sequence program formed by a plurality of contacts or windings each given an actual address representing a name of a mechanism such as a truck, a lifter, a slide or the like which forms a system to be controlled and the action of which is to be controlled to control the system, a name of an action of the mechanism and a name of a controlled device such as a switch, a solenoid valve, a motor and the like which is directly controlled to control the action of the mechanism is prepared.

Abstract: A versatile switching module to control the switching operation of multiple relay switches and to monitor the status of each relay includes a driving card and multiple relay cards, each relay card in turn including a number of relays, with each relay representing a testing channel made up of three testing terminals. In one embodiment, one driver card may be used to control four relay cards, each relay card having sixteen relays and each relay having four single-pole double-throw switches.

Abstract: A controller for controlling equipment in response to control signals received by the controller. The controller includes control line inputs, a switching arrangement, control outputs and binary switching devices. The switching arrangement is configured to selectively couple each control line input to either zero, one or more than one control output. The binary switching devices may be configured as relays to control the application of an electrical signal, such as a power line input, to electrical devices. A single control signal may control the application of multiple phases of power to one electrical device or control the application of power to several electrical devices. The binary switching devices may also be configured as solenoids coupled to mechanical devices such as valves.

Abstract: A submarine cable branching system includes a plurality of directional relays in respective power feed paths branched at a common node, each of the directional relays being energized by a current flowing through the power feed path in a predetermined direction for energizing a corresponding switch provided in a different power feed path to establish a bilateral feed path and further a unilateral feed path, wherein there is provided a bypassing switch across one of the switches that forms the bilateral feed path, such that the bypassing switch is urged to close in response to energization of a self-sustaining relay provided in the unilateral feed path.

Abstract: In a circuit configuration for monitoring a plurality of coils and the final stages for actuating these coils, the coils are connected to the supply voltage by way of a joint supply line and a joint relay. Connected to the supply line, by way of a high-ohmic resistor, is a test voltage source and a first potential monitor, by which the potential prevailing on the supply line is determined after the voltage supply has been interrupted by opening the relay contact. A second potential monitor serves to monitor the proper potential changes on activation of the voltage supply by actuating the relay.

Abstract: In a relay switching panel, a switching circuit operates to selectively connect and disconnect resistive, capacitive and inductive loads to an AC power source with substantially no arcing. The switching circuit comprises a pair of relays, preferably connected in parallel, with one of such relays having a triac, connected in series therewith. With the relays open, an air gap isolates the power source and the load. In closing the relays in sequence, one relay provides a conductive path from the power source to the triac. After a suitable delay to allow the relay contacts to stabilize in the closed position, the triac is triggered to provide a conductive path from the power source to the load, and a large current surge flows to the load. After the current surge has subsided, the second relay is closed to provide a direct conductive path between the power source and the load. Next the first relay and the triac are removed from the circuit to ensure full conduction through the second relay.

Abstract: In order to accomplish the present invention, there is provided a voltage supply system for use in a color electrophotographic printer where the electrophotographic printer has more than one developer. A high voltage AC source receives a select signal that indicates which one of the developers is presently in use. Provided one and only one developer is in use, the alternating current source outputs an AC voltage. A switching network is connected to the HVAC current source and also each developers. The switching network also receives the select signal and routes the AC voltage to the active developer. Stress to the switching elements in the switching network is reduce by proper sequencing of the application and removal of the HVAC and network reconfigurations.

Abstract: An electromagnetic lock employs a pre-wound bobbin which is forced onto the E-shaped lamination stack of a magnetic core. The housing is configured in two longitudinal sections which are relatively pivotal to provide access for circuitry within the housing for both an outswinging and an inswinging door lock installation. The electromagnet also employs a circuit to sense the power supply to the electromagnet and to automatically select the operating voltage of the electrical coil.

Abstract: A photodetection system and related circuitry designed to sense the intrusion of an opaque object in a light plane. Upon sensing the intrusion, the system quickly initiates a machine-stopping sequence prior to the opaque object coming into contact with the machine while that machine is operating. The system comprises a SYSTEM microcontroller and a WATCHDOG microcontroller, both of which operate an output control device of the light curtain switch of the invention, wherein the output control device comprises a plurality of electromechanical relays. Both microcontrollers also perform system hardware and software integrity checks. Furthermore, the WATCHDOG microcontroller evaluates the performance of the SYSTEM microcontroller by transmitting a false intrusion signal to a photosource, determining whether the false signal has been detected, and then verifying that the SYSTEM microcontroller has initiated the machine-stopping sequence.

Abstract: A method for triggering a plurality of relay exciter coils connected parallel to a common voltage source includes turning each of the coils on and off with relay switching means associated with the coils, and triggering the respective coils to be turned on after reaching a response state thereof with a common clock generator having a given clock ratio, through the relay switching means, for establishing a steady state of a holding current being reduced relative to the response state. The method further includes turning off the coils with a common OFF-switch, keeping the respective relay switching means closed for those coils being intended to continue to be operated in the steady state of the holding current, for establishing a response current rising within a short time within the associated coil, and triggering the coil again with the clock generator having the given clock ratio after a predetermined period of time.