Abstract: Method for monitoring a load circuit with an electronic flasher relay. In known methods, the comparison threshold is obtained from a voltage measurement made during operation and stored in a volatile memory in order to record a load element failure. If the load elements malfunction during voltage measurement, incorrect comparison thresholds are defined. In accordance with the method according to the invention, the characteristic values for determining the voltage thresholds are stored in a non-volatile memory before the load circuit commences operation. Thus, no malfunction can occur as a result of incorrectly defined comparison thresholds.

Abstract: A relay driving apparatus is provided to be automatically able to restore a relay driving state while no keeping under the relay driving state. In a relay RL1 driving apparatus for once subjecting a relay RL1 to a rated driving operation by supplying a predetermined rated voltage to the relay RL1 and shift the relay RL1 to a driving state, and then reducing the voltage to keep the driving state of the relay RL1, the driving state of the relay RL1 is monitored, and on the basis of the monitoring result the relay RL1 is subjected to the rated driving operation, or the rated voltage is periodically supplied to the relay RL1 kept under the driving state, or after a predetermined rated voltage is supplied to the relay RL2 to set the relay RL2 to a driving state or non-driving state, the state is monitored and the relay RL2 is periodically subjected to the rated driving operation on the basis of the monitoring result, thereby enhancing the operation reliability with promoting the energy saving.

Abstract: The hydraulic multiway valve comprises a control piston (main piston 3), which is displaceable against the force of a spring (main spring 18) by the plunger of a magnet (12) from its first position (closing position) to its second position (opening position). In the closing position, a pressure chamber (7) with a pump connection (P) is closed toward a consumer chamber (8), and the consumer chamber with a consumer (A) is opened toward a return flow chamber (20) and a reservoir connection (R). In the opening position, the consumer chamber (8) is closed toward the return flow chamber (20). To this end, the consumer chamber (8) and the return flow chamber (20) are arranged at the opposite ends of the main piston (3), namely the consumer chamber (8) on the side facing the magnet, and the return flow chamber (20) on the side facing away therefrom. A central channel (21) extends through the main piston. The central channel interconnects the consumer chamber (8) and the return flow chamber (20).

Abstract: A method and apparatus for testing a thermal tripping mechanism having a bimetallic element deflectable in response to overload current by heating the bimetallic element by radio frequency induction heat.

Abstract: Electrical consumers receive load current from a supply voltage via two or more power switches. A false-closure detection device includes a measuring device and a diagnostic device for the detection of faults. The measuring device is connected parallel to the power switches and the electrical consumer lying in series with the switches. A diagnostic voltage is compared as the output signal of the measuring device with a reference value for the detection of false closures in the load circuit.

Abstract: Due to a bimetallic contact point, a fine control is out of sight. Further, dispersion of bimetal characteristics and poor durability of a contact point cause problems, particularly in maintenance work. In order to overcome these problems, a controller for extending a service life of the contact point can provide a fine control, so that a maintenance-free electric cooker can be provided. The ON/OFF of the contact point of relay is controlled to operate at zero potential of commercial power, and a short-pulse-signal-switch that allows the relays to remove deposition by itself even if the contact point encounters deposition, are prepared and applied to plural heaters for controlling thereof.

Abstract: A lightning arrester tester includes two tubular poles respectively carrying probe terminals, one probe terminal being connected in series through a high-voltage rectifier and high-resistance circuit disposed within the pole to one terminal of a DC microammeter mounted on the outside of the one pole, the other probe terminal being connected through a high-resistance circuit housed within the second pole to the other meter terminal. A diode is connected in parallel with the meter to protect the meter from high leakage currents. In use, the probe terminals are respectively connected to a high-voltage power transmission or distribution line and one terminal of an arrester, the other terminal of which is grounded or, alternatively, to ground and to one terminal of an arrester, the other terminal of which is connected to a high-voltage power transmission or distribution line. The meter displays DC leakage current through the arrester.

Abstract: A method and apparatus for the recognition of the state of a solenoid valve supplies an on/off control switching current to the coil of the solenoid valve. A high level of current is caused to flow through the coil for switching the device on, and a reduced level of current is applied to the coil for holding the solenoid armature in its on position. If the armature should be caused to drop off from its on position by a mechanical shock, an increase in the frequency of the switching current occurs, due to the decrease in magnetic circuit inductance. This frequency increase is detected and compared to a predetermined threshold value. If the detected frequency exceeds the threshold value, it is recognized as an armature drop off, and corrective action can be taken immediately.

Abstract: A method of detecting a fault of an electromagnetically-actuated intake/exhaust valve is disclosed. A valve body is supported in neutral position by the energizing force of an elastic member, and the electromagnetic force generated by supplying a current to the coils arranged on the two sides of a plunger is applied to the plunger thereby to operate the valve. A fault is detected based on a change of the current flowing in one coil attracting and holding the plunger with the inductance change of the same coil when the plunger is switched from the position of the same coil to the position of the other coil. This method improves the fault detection accuracy for the electromagnetically-actuated intake/exhaust valve over the prior art.

Abstract: A method of adjusting the position of rest of an armature of an electromagnetic actuator, reciprocated against the force of resetting springs by an alternating energization of two spaced electromagnets; the position of rest being assumed by the armature in the de-energized state of the two electromagnets. The method includes the steps of detecting and determining actual values of an impact indicator representing an impact behavior of the armature as the armature impacts on the pole face of the capturing electromagnet; comparing the actual values derived from both electromagnets with predetermined desired values to form deviation values between the actual and the desired values; and, if deviation values are present, shifting the position of rest of the armature by an adjusting device until the actual values derived from both electromagnets correspond to a predetermined desired value.

Abstract: A method and system for detecting degraded operation of a solenoid. A current through the solenoid is sampled at predetermined time intervals within a predetermined time period. A maximum value of the sampled current is first detected. Next, a minimum value of the sampled current subsequent to the maximum value is detected. Finally, a predetermined increase in the sampled current from the minimum value is detected to verify operation of the solenoid.

Abstract: A solenoid actuation detection device for detecting actuation of an armature of a solenoid includes a sensor for sensing electric current flowing through a solenoid, a peak detector for receiving the sensing signal and for creating a peak signal from the sensing signal, and a comparator for comparing the two signals to determine when an armature of the solenoid was actuated.

Abstract: An electromagnetic switch for opening and closing a set of contacts has a microprocessor which monitors coil current to determine the state of the contacts. The switch relies on the phenomenon that the inductance of the switch coil changes significantly between the open position of the contacts when the switch armature carrying the moveable contact is spaced by an air gap from the core of the electromagnet, and the closed position in which the armature abuts the core. For an AC energized coil, which is self-limiting in that the increase in inductance from closing of the contacts reduces the current to the holding value automatically, a coil current of less than about one/half of the nominal open contact value is an indication that the contacts are closed.

Abstract: A system and method for automatically testing the operation of a protective relay system is disclosed. The system and method provide for continuous testing to ensure proper operation of the protective relay system while the relay remains in service and without interrupting the normal operation of the relay. This testing is performed by storing reference data corresponding to test signals, generating test signals, sampling a specific test signal, processing that test signal through the relay and comparing the processed test signal with the corresponding reference data. Upon detection of an error in the relay, the system and method further provide for isolation of the relay from the electric power system and automatic testing of individual electrical components within the protective relay system to determine the identity of the malfunctioning component.

Abstract: A method of detecting when a moving component of an electromagnetically operable device attains a final position after de-energizing a winding of the device comprises allowing the energizing current to fall to zero and prior to the component reaching its final position, connecting a sensing circuit in parallel with the winding, the current flow in the sensing circuit increasing from the instant of connections and decreasing when the component reaches its final position, said sensing circuit detecting the change in current flow.

Abstract: A relay test apparatus for testing a protective relay operation of a protective relay system comprises GPS receivers, respectively connected to the protective relays, each GPS receiver analyzing time data included in a signal transmitted from a satellite and outputting a time signal, simulation signal generators, respectively connected to the protective relays, each simulation signal generator generating a simulation signal and inputting the simulation signal to a corresponding protective relay, and synchronous starting units, respectively provided in the protective relays, each synchronous starting unit starting a corresponding simulation signal generator to generate the simulation signal, when time signals output from the GPS receivers coincide with a preset time at a same time.

Abstract: An apparatus and method for determining the state of a switch for use in an HVAC system. The apparatus and method are advantageously configured for use within a heating, ventilation and air conditioning (HVAC) system, in which the sensing of the state of safety switches external to a controller is desirable. A current sensor coupled in series between a current source, a safety switch, and a current load, detects the flow of current from the current source and through the switch and load. A status signal, indicative of the flow of current through the current sensor, is generated for sampling by a microprocessor. The presence or absence of current flow through the current sensor provides an indication as to whether the remotely-located switch is in an open or closed state.

Abstract: A relay test apparatus for testing a protective relay operation of a protective relay system comprises GPS receivers, respectively connected to the protective relays, each GPS receiver analyzing time data included in a signal transmitted from a satellite and outputting a time signal, simulation signal generators, respectively connected to the protective relays, each simulation signal generator generating a simulation signal and inputting the simulation signal to a corresponding protective relay, and synchronous starting units, respectively provided in the protective relays, each synchronous starting unit starting a corresponding simulation signal generator to generate the simulation signal, when time signals output from the GPS receivers coincide with a preset time at a same time.

Abstract: A composite switch is constituted by a series or parallel association of at least two simple switches. Each simple switch includes an element for measuring the current in the simple switch in the case of a parallel association; an element for measuring the voltage across the simple switch in the case of an association in series; and a control circuit receiving the information provided by the measuring elements as well as a control signal from the simple switch, and providing an active failure signal if the measured voltage is high or the measured current is low while the simple switch is controlled to be turned on, or if the measured current is high or the measured voltage is low while the simple switch is controlled to be turned off.

Abstract: The invention refers to a system for the technical safety check of solenoid valves, where during an operational switch of the solenoid valve, the induction current of the actuating magnet of the valve is recorded over time and stored as test function I=I(t). From the test function the control function I'=dI/dt is digitally calculated and after digital logarithmation also stored. Both functions may be displayed and evaluated simultaneously on the screen, which assures a better and more exact evaluation of the functional condition of the concerning solenoid valve, including any existing defects.

Abstract: In order to provide a dependable check on the reliable functioning of contacts of switches or relays which control a control device, to ascertain whether they occupy the desired rest contact position and/or have a sufficiently high mains voltage, the rest contacts of the two switches can be connected in parallel by way of a respective electrical resistor to a pole of the voltage source and both resistors can be connected in series to a charging capacitor which, upon the attainment of a given electrical charge or voltage (threshold voltage) activates the control device and in particular feeds a threshold switch or itself serves as such.

Abstract: In one aspect of the present invention, an apparatus detects a shorted winding condition of a solenoid coil. The apparatus includes a reference solenoid that is connected to a test solenoid. A sine generator drives the reference solenoid with a sinusoidal waveform to cause an induced voltage across the test solenoid. A meter determines the voltage difference between the solenoids and compares the voltage difference to a predetermined value.

Abstract: A relay test assembly constructed of a majority of parts adapted to be injection molded and capable of withstanding large and rapid swings in temperature and humidity. These include a central approximately cylindrical body portion having a plurality of channels running therethrough generally-parallel to the axis of the body portion. The channels provide easy entry to leads of a relay. Each channel includes a spring contact which may be brought to bear against a lead positioned in the channel to provide positive electrical contact to the lead so that connection may be made to sources of potential or current. A second set of contacts surrounds the first set and may be brought to bear against a lead positioned in the channel to provide a second more positive electrical contact to the lead closer to the relay through which testing may be conducted. A sleeve positioned about the body portion is shaped to move the springs into contact with the relay leads and retract the springs.

Abstract: The relay includes an input module capable of receiving 70 volt and 5 amp signals, respectively, from conventional instrument transformers, which are responsive to power line signals at their primaries. Output signals from the input module have specified, standardized levels suitable for electronic processing circuits, i.e. 1.4 volts and 0.1 volt. The output signals from the input module are applied through an accessible connector to a separate processing module which uses those signals in a conventional manner to determine possible faults on the power line. Low-level testing is accomplished by testing the outputs of the input module and by applying test signals simulating the standardized outputs of the input module to the processing module.

Abstract: A non-invasive apparatus and method is disclosed which is adapted for testing of solenoid valves to verify valve operation. The non-invasive apparatus and method monitors with time both the stroke of the solenoid valve plunger to identify associated impacts and the state of the solenoid valve as being energized or de-energized to determine valve operability.

Abstract: A relay test assembly including a majority of parts adapted to be injection molded and capable of withstanding large and rapid swings in temperature and humidity. These include a central approximately cylindrical body portion having a plurality of channels of generally-conical shape running therethrough generally-parallel to the axis of the body portion. The channels provide easy entry and straightening to leads of a relay Each channel includes a spring which may be brought to bear against a lead positioned in the channel to provide positive electrical contact to the lead while requiring no force to insert the lead. A sleeve positioned about the body portion is shaped to force the springs into contact with the relay leads.

Abstract: An improved monitoring system which identifies the particular event (contact operation) and therefore the particular electromechanical relay (20, 22, and 24 which operated). This information is output from a MCU (30), along with the relative time the event occurred, to a PC and an LCD display (40). In addition, the relative occurrence time is recorded to the thousandths of a second.

Abstract: A tester for individually testing diode packages, double pole relays and single pole relays includes a circuit contained within a housing, which circuit connects the diode package or relay being tested to a source of 12-volt direct current and transmits the direct current through the diode package, or relay, to an array of indicator lamps under the control of one normally open and two normally closed switches. A forward and reverse bias switch controls the direction of current through the diodes of the diode package and the internal diode of the relays to determine if the diodes and internal diode are oriented properly and conduct current properly.

Abstract: The present invention is directed to a method for determining actual tripping characteristics with the aid of a test apparatus in which test parameters are input with the aid of an input unit. The aim is to specify an appropriate method which works particularly quickly and precisely. This can be achieved when a theoretical tripping characteristic of the respective protective relay is stored in the test apparatus. Each measurement point of the actual tripping characteristic is determined on a locating straight line, the starting point for the measurement being a point of intersection of the locating straight line with the theoretical tripping characteristic. In this case, the locating straight line dissects the theoretical tripping characteristic at an angle. The angle is situated in a range from 60.degree. to 120.degree., 90.degree. being preferred.

Abstract: The invention relates to a data input module for inputting data, by means of electrical contact, to a monitoring/control module, the module including a first voltage feed input (1) and a second voltage feed input (2), which inputs are intended to be subjected to a potential difference which is optionally variable, and a plurality of contacts (3) each of which has a first terminal (4) connected to the first input via a first resistor (14), and a second terminal (5) connected to the second input (2), each contact being designed to open or to close an electric current path between its terminals. The module further includes detection members (7) respectively associated with the contacts. Each detection member is organized to detect the presence or the absence of current flowing between the terminals of the contact with which the detection member is associated.

Abstract: An electromagnetic relay having an uncomplicated and cost-effective construction includes a switching contact spring (5) that is adjustable in a particularly uncomplicated manner for controlling actuation sensitivity. In this manner, in particular, actuation can be influenced by a value of a minimum attraction voltage.

Abstract: A circuit is provided for detecting abnormal conduction of current conducted through a solenoid in response to the pulse width modulation signal. The circuit includes a measuring means, for detecting conduction current conducted through the solenoid in response to the pulse width modulation signal and measuring continuous conduction time of the conduction current, and determining means, for determining a conduction to be an abnormal conduction when the continuous conduction time is longer than a predetermined time. Thus, the circuit can be miniaturized and the accuracy of the circuit is not affected by the accuracy of its components. And, the circuit is capable of detecting the half short state of the transistor driving the solenoid and not malfunctioning even if tile power is turned off.

Abstract: The invention relates to a method for the supervision of a switch, in which a switch supervision signal (CA1, CA2, CB1, CB2) is generated and transmitted to the switch contact to be supervised, and in which the switch supervision signal (CA1, CA2, CB1, CB2) returning from the switch contact is detected and compared with the emitted signal. A coded signal is used as switch supervision signal (CA1, CA2, CB1, CB2) and this coded signal is transmitted serially to the switch contact to be supervised.

Abstract: Load driver system (10) preferably uses a microprocessor controller (20) to generate write/read signals and command signals received by a circuit at write/read and command/status input terminals (16, 17). The circuit (15) responds to the input signals and controls a semiconductor switch (11) that controls the operative state of a load (14). The circuit (15) includes a load shorted high detector (28), a load shorted low detector (29) and a load open detector (30) which are used to detect various faults and provide a predetermined sequence of logic states at the command/status input terminal (17) during read cycles implemented by the controller (20). Thus one input line (terminal 17) is used to both send commands to the semiconductor switch (11) and receive a sequence of logic states indicative of various fault modes. This permits the controller to determine which of several types of faults, if any, has occurred, while minimizing the number of controller-circuit interconnections.

Abstract: Open-circuit and closed-circuit faults in a solenoid controlled actuator are detected using shunt resistors (R1, R4) across the solenoid (1), a transistor switch (4), and a voltage monitor (7) and/or (14) across one or both of these which can detect a faulty open-circuit solenoid that is not energized, or a faulty closed-circuit solenoid that is energized. According to the present invention, before each change in actuator position, the solenoids are all caused to assume an opposite energization condition for a period of time insufficient to move the actuator, but enough to check the voltage monitor responses. In this way, both open and closed circuit faults are detected.

Abstract: A computerized relay tester is provided which comprises a bar code reader, a test circuit for determining an actual value of an operational characteristic of the relay, and a memory for storing reference values for the operational characteristic for a plurality of relays. The test circuit is operative to automatically measure the actual voltage or current values at which "pickup" or "drop away" occurs in the relay under test, by sensing an inductive voltage "spike" caused by movement of the relay armature. Based on signals from the bar code reader, a reference value for the particular operational characteristic under test are retrieved from memory. The actual value is then compared with the reference value to determine whether the relay is functioning properly, and the relay tester outputs an indication of the operational state or condition of the relay.

Abstract: A circuit is provided for detecting the deposition of an electromagnetic contactor which opens and closes a drive circuit connecting a power source to a load. A load current of the drive circuit and an operating current for operating the electromagnetic contactor are detected and applied to a detection circuit. The thus detected load current and operating current are used to determine the deposition of the electromagnetic contactor. Further, in the event of a detected malfunction in the electromagnetic contactors, a breaker of the drive circuit is automatically opened.

Abstract: When a solenoid has been turned on by supplying current to a coil thereof, the solenoid operation is checked by temporarily ceasing the supply of current to the coil to temporarily deenergize the solenoid. The current flowing in the coil is detected while the solenoid is temporarily deenergized, and the characteristics of the thus detected current are used to discriminate the position of a movable iron core of the solenoid. On the other hand, when the solenoid has been turned off by ceasing the supply of current to the coil, the solenoid operation is checked by temporarily supplying current to the coil to thereby temporarily energize the solenoid. The current flowing in the coil while the solenoid is temporarily energized is detected, and the characteristics of the thus detected coil current are used to determine the position of the movable iron core of the solenoid.

Abstract: A fusion detecting system for relays is provided for detecting a fusion of relay contacts. Two fully-interlocked or semi-interlocked relays are connected in such a manner that they operate under identical conditions, and a fused state is detected based on the states of signals sent from series-connected make contacts and series-connected break contacts of the two relays. In the case of semi-interlocked relays (R1, R2), if a make contact (r12) is fused during a current supply to a coil, the other contact (r22) remains in an open state or at a make-contact side after the current supply to the coil is cut off, and if a break contact (r11) is fused, the other contact (r21) remains in an open state or at break-contact side after a current is supplied to the relay coil.

Abstract: An electromagnetic contactor assembly with a sensing circuit for determining contactor state based upon the reluctance of the contactor coil. The coil has an electromagnetic coil and a movable contact separated from the coil by a gap when the coil is not energized. Energizing the coil causes the movable contact to close the gap and contact the coil. The determination of the relationship between the reluctance in the coil when the gap is in an open and closed state allows contactor gap status to be measured by measuring the coil inductance. A sensing circuit is added to the drive circuit to measure changes in AC current during the pulse cycle which holds the contacts in this closed position. The sensing circuit measures the AC current and is able to signal contactor status based on that value.

Abstract: A shutter, positioned between an electronic imaging device (such as a laser printer) and a film processor, is actuated by a solenoid which is driven by a driver network which isolates the solenoid coil when it is deactuated. If, after deactuation, a jam occurs, such that the shutter does not close completely, the jam is detected by a solenoid engagement sensing circuit. The sensing circuit includes a function generator, an operational amplifier having the solenoid coil connected between its input and output, an envelope detector and a comparator. The comparator produces a jam signal in response to an increase in the voltage detected by the presence of the solenoid plunger within the solenoid coil.

Abstract: A method for detecting the motion and position state of a component of an inductive electric load. The component can be moved between two end positions by magnetic interaction, in which the total waveform of the drive current is divided into a plurality of states. By evaluating these individual states, comprehensive error diagnostics and a setting of operating parameters of the inductive electric load to operating conditions are possible.

Abstract: Disclosed herein is a device for detecting an occurrence of abnormal condition accurately in a load such as a plurality of fuel injectors for use in an internal combustion engine or the like with a single abnormality determining circuit.

Abstract: An apparatus for detecting a failure in a solenoid valve having an electrical winding electromagnetically coupled with a plunger. The failure detecting apparatus comprises a current sensor sensitive to a current through the electrical winding for producing a signal indicative of a sensed winding current. Changes in the sensed winding current indication signal with time are monitored to provide a failure signal which indicates a failure in the solenoid valve when no inflection point exists in the change of the sensed winding current indication signal for a predetermined period of time after power is supplied to the electrical winding.

Abstract: A relay device having a relay element mounted on a circuit board, the relay element having a pair of contacts which are closed and electrically conducted by a control signal of a first level and opened by the control signal of a second level to form a contact gap; an LED for emitting light toward the contact gap; a phototransistor for receiving light from the LED, the phototransistor not receiving the light while the pair of contacts are closed, and receiving the light passing through the contact gap while the pair of contacts are opened; and a checker circuit for checking if the relay device operates normally or abnormally in accordance with the relationship between an output from the phototransistor and the level of the control signal.

Abstract: A tester for a vehicle engine idle air control system includes an air bypass valve operated by a solenoid which receives a pulse width modulated signal to control the degree of opening of the valve. The tester is inserted in the vehicle wiring harness and includes a manually controlled pulse width modulator for generating a test voltage to the solenoid. A switch is connected within the tester to switch between engine computer control or manual modulator control of the solenoid. A bar graph display monitors the voltage supplied to the solenoid to indicate the magnitude thereof. The bar graph display also indicates the occurrence of short or open circuits.

Abstract: A circuit for correcting a fault in an automotive system having at least two operating states includes an actuator mechanism for placing the system into one of at least two operating states and a switching mechanism, such as a relay, operatively connected with the actuator mechanism for driving the actuator mechanism upon passing a current through the switching mechanism. The circuit further includes a fault warning mechanism for detecting an inability of the actuator to place the system into a desired operating state and for generating a fault warning signal in response to the detection as well as a control unit for activating the switching mechanism according to a predetermined sequence upon generation of the fault warning signal to correct the inability of the actuator mechanism to place the system into a desired operating state.

Abstract: A circuit configuration for monitoring the final stages of a plurality of valves, particularly the power transistors (LT1-LT4) and their circuitry, for defects as well as for leakage currents or by-path currents comprises a comparator circuit (1), an OR-link (2) and of a further comparator element (XOR4). By way of the monitoring circuit, the actuation connections (S1-S4) of electromagnetically operable valves are connected to a sole output (A3). By applying short test pulses to the actuation inputs (E1-E4) of the final stages (LT1-LT4) and by comparing the signal variation at the output (A3) with the test pulse variation defects, leakage currents and the like are detected.

Abstract: A mini-relay signal tester designed to simplify, speed up, and test the operation of "mini" or "reed" relays which are suspected of intermittent failure. These types of relays are extensively used in memory and gate-array testing systems and their failure can cause the semiconductor devices being tested to be erroneously rejected. The relay tester dynamically exercises the relay being tested by application of a square-wave input signal to its coil. The square wave input "reference" signal driving the relay coil is then compared to a square wave output "test" signal which is generated by the contacts of the relay being tested. The signals are compared on a dual-trace oscilloscope. When difference between signals exceeds acceptable standards the relay is rejected.

Abstract: The disclosure describes a tester for determining the operating condition of a Reed Relay Printed Circuit Board (PCB) device. A Reed Relay PCB to be tested is connected directly to the tester for testing in a data flow per path environment as it would be functionally connected with a data acquisition system, such as a "Ramp Scanner" model 128RR by Kaye Instruments, Inc. The tester develops accurate voltages for the test and connects them for powering components as well as for simulating data flow. As each data flow path is sequenced in its turn, the time of opening of a previous relay contact as a next contact is closed is monitored, and if it exceeds a predetermined amount of time, a visual indicator light is energized and latched in its energized state. Also, the tester includes other test circuits for testing the operating functionality of each data flow path.