Abstract: A back end of the line (BEOL) fuse structure having a stack of vias. The stacking of vias leads to high aspect ratios making liner and seed coverage inside the vias poorer. The weakness of the liner and seed layers leads to a higher probability of electromigration (EM) failure. The fuse structure addresses failures due to poor liner and seed coverage. Design features permit determining where failures occur, determining the extent of the damaged region after fuse programming and preventing further propagation of the damaged dielectric region.

Abstract: A system is provided that includes: a sensor device adapted to selectively monitor a plurality of sensors, wherein the sensor device includes a wireless transceiver within the sensor device adapted to transmit measurement information from the selected sensor; and a receiver indicator device adapted to wirelessly receive the measurement information from the sensor device, and provide an indication based on the measurement information to a user operating the receiver indicator device.

Abstract: A system and method is provided for correcting alignment of a product on a tool and, more particularly, to a system and method for correcting alignment of a wafer on a chuck of a tool. The system is a tool including at least one contact near a circumference of the tool and a grounded contact proximate to the at least one contact.

Abstract: The presently disclosed subject matter relates to powerline communications (PLC) in an advanced metering infrastructure (AMI) environment. A communications signal is applied to a power line by a PLC transmitting device. A receiver is provided that evaluates communications signals based on the power coupled to the power line by the transmitting device. In one present embodiment, PLC signal voltage and current levels are multiplied together to evaluate signal power to reproduce received PLC signals.

Abstract: A wiring testing device configured to test the wiring correctness of an inverter is disclosed. The inverter is configured to be connected to a low-voltage three-phase system with a neutral conductor serving as a reference point for grid-side conductor voltages. The wiring testing device includes a test circuit configured to measure the grid-side conductor voltages and determine an average value from the sum of the instantaneous values of the grid-side conductor voltages, and a display unit configured to display an error message if the average value exceeds a threshold voltage for a defined time period. The wiring testing device further includes a capacitor connected between a phase of the three-phase system and the neutral conductor configured to generate a voltage imbalance if the neutral conductor connection is missing, wherein the test circuit is configured to measure the conductor voltages and determine the voltage imbalance.

Abstract: A circuit breaker having internal power monitoring and data signal generating apparatus, and a system for utilizing such a circuit breaker in a facility having a plurality of tenants served by branch circuits from a plurality of distribution panels. The circuit breaker radiates signals indicative of power consumption of the branch circuit protected thereby, together with a unique address identifier tied to one tenant. Electrical billings are based on summing all signals for each tenant. Changes to branch circuits during tenancy will not disturb correct billings since individual circuit breakers are associated with that tenant using power supplied by each branch circuit. Hence changes to branch circuits may be limited to modify building space locations served by the modified branch circuit, and need not be further modified to maintain correct billing in light of the circuit changes.

Abstract: The claimed invention relates to the power industry and can be used for locating short circuits in power transmission lines by measuring the instantaneous current and voltage values when unsynchronized measurements are taken at both ends of the line. It is a technological object of the invention to improve the accuracy of damage location. The technical result of the invention is achieved by accurately synchronizing the current and voltage values measured at the ends of the line and unsynchronized in time on measurement. Synchronization is effected by aligning the oscillograms at both ends of the line with the short circuit start section.

Abstract: The invention relates to a method for igniting a fuel-air mixture in an internal combustion engine. An electric transformer excites an oscillating circuit connected to a secondary winding of the transformer. A capacitor is formed by an ignition electrode together with the wall of a combustion chamber through which it extends. The excitation of the oscillating circuit is controlled by generating a corona discharge igniting the fuel-air mixture. Before each ignition time the voltage applied to a primary winding of the transformer is incrementally increased, and the intensity of the current flowing in the primary winding is measured repeatedly at the same primary voltage. The variation of the values of the related primary current is determined, and the incremental increase in the primary voltage is aborted at a value thereof at which the variation of the primary current intensity reaches or exceeds a predetermined limit.

Abstract: A comparison judgment circuit judges the level of a signal received, via a transmission line, from a second device which is a communication partner. An input/output terminal is connected to the transmission line. An attenuator circuit attenuates the voltage at the input/output terminal so as to generate an attenuated voltage. A level comparator compares the attenuated voltage with a predetermined threshold voltage, and generates a level judgment signal that corresponds to the comparison result. A protection circuit monitors the voltage at the input/output terminal or the attenuated voltage. When the voltage to be monitored deviates from a predetermined voltage range, the protection circuit forcibly cuts off or changes the voltage input to the level comparator.

Abstract: A method is provided for detection of a ground fault in a high resistance network in a voltage source power conversion circuit comprising a power converter that converts incoming AC power to DC power applied to a DC bus and an inverter that converts DC power from the DC bus to output AC power. The method includes detecting a midpoint-to-ground voltage between a low side of the DC bus and a ground potential and detecting the presence of a ground fault in a high resistance network based upon the detected midpoint-to-ground voltage.

Abstract: A measurement apparatus includes a display unit, a current detection unit configured to output a detection signal if an increase in a consumption current of the display unit is detected, a plurality of setting units each of which is configured to output an output signal, each of the plurality of setting units changing the output signal if the detection signal is received, and a diagnosis unit configured to receive the output signal, the diagnosis unit diagnosing the increase in the consumption current.

Abstract: The invention relates to an electrical power tool, particularly an electric hand power tool, for operating with alternating current, having an electric motor, and electronic control device, and an electrical power switch for actuating the electric motor, wherein the electronic control device comprises a bias voltage output and a detection input, connected to each other by means of a voltage divider comprising a summation point and to the side of the power switch facing the electric motor, and the control device is further designed such that the potential at the detection input is monitored after actuating the power switch and used for checking whether the power switch is conducting, and that it is actuated again if the power switch was not conducting or returned to the non-conducting state during the monitoring, and that said checking and any renewed actuation of the power switch is repeated within a half-wave of the alternating voltage.

Abstract: A display panel and a testing method of the display panel are provided. The display panel has a display region and a non-display region and includes a first substrate, a second substrate, and a display medium. The display panel further includes scan lines, data lines, pixel units, at least one testing line, and at least one testing pad. The scan lines and the data lines are located on the first substrate within the display region. The pixel units are located on the first substrate within the display region. Each pixel unit electrically connects one of the scan lines and one of the data lines. The testing line is located on the first substrate within the non-display region, crosses over the scan lines, and is insulated from the scan lines. The testing pad is located on the first substrate within the non-display region and electrically connected to the testing line.

Abstract: A diagnostic circuit is configured for connecting to a unit under test that has a load and a sinusoidal source. The diagnostic circuit includes a voltage sensing device that has an input for sensing a signal, a first terminal for connecting to the load, a second terminal for connecting to the sinusoidal source, and a relay connected between the first and second terminals for connecting the sinusoidal source to the load. Clamping diodes are provide for clamping a sinusoidal signal and include a first clamping diode connected between a D/C voltage source and the input and a second clamping diode connected between ground and the input. A resistor is connected between the D/C voltage source and the first terminal. The diagnostic circuit verifies the operational functionality of the load, related wiring and connections.

Abstract: There is provided a semiconductor light source device including a plurality of semiconductor light source elements connected in series, a drive circuit configured to drive the semiconductor light source elements, a plurality of resistors, each of which is connected in parallel with one of the semiconductor light source elements, respectively, and a determination unit configured to determine the number of elements short-circuited in the semiconductor light source elements based on voltages applied to the resistors when driving of each of the semiconductor light source elements is being stopped.

Abstract: Embodiments of an apparatus for measuring the leakage current of capacitive components is taught. One embodiment includes a first stage amplifier configured to receive an input from a serially-connected capacitive component at an inverting input and a feedback resistor in a feedback path of the first stage amplifier. A resistance value of the feedback resistor is programmable based on an expected value of the leakage current and a corresponding voltage output.

Abstract: An apparatus and method for burning-in an electronic ballast for a lamp. The apparatus comprises a first stage for emulating an input impedance characteristic of a lamp for the electronic ballast and a second stage connected to the first stage for providing energy feedback to a power supply. An input of the first stage connects in use to the electronic ballast to be burnt-in. An output of the second stage connects in use to the power supply to provide energy feedback to said power supply from the electronic ballast being burnt-in. The energy-recyclable burn-in apparatus can emulate the lamp characteristics from start up to the steady state, process high-frequency ballast output power and recycle the power back into the power grid. The burn-in method includes operating the apparatus for a predetermined period of time such that a voltage applied to the electronic ballast simulates a steady-state operation of a lamp for the electronic ballast.

Abstract: Embodiments of the present invention include systems, methods, computer-readable media, and computer programs to determine and locate one or more faults on a distribution network in a high resistivity area. Embodiments of the present invention include a plurality of open conductor devices positioned on lateral ends of a plurality of distribution transformers. Each of the plurality of open conductor devices are configured to, for example, determine abnormal voltage readings and communicate such readings to a master station over a GSM/GPRS communication network. The master station, in accordance with embodiments of the present invention, is configured to determine or verify the presence of one or more faults on the distribution network and the location of the one or more faults.

Abstract: A system and method for filtering electric power system data communicated from faulted circuit indicators (FCIs) and at least one other source before the electric power system data is further communicated to a monitoring system such as SCADA. The power system data from the FCIs may include an event such as a fault on the electric power system. To avoid sending incorrect or excess information along to the monitoring system, the present disclosure describes a system and method for comparing data from the FCIs against electric power system data gathered either directly from the electric power system or from an intelligent electronic device (IED). If the two sets of data agree, then the information is passed on to the monitoring system. The FCIs may communicate to a transceiver interface periodically, upon detection of an event, and/or upon interrogation by the transceiver interface.

Abstract: According to one aspect, embodiments of the invention provide a system for monitoring a plurality of circuit branches, the system comprising a plurality of current sensors, each configured to be coupled to at least one of the plurality of circuit branches and to produce a signal having a level related to a current level of the one of the plurality of circuit branches, a communications bus, a plurality of sensor circuits, wherein each one of the plurality of sensor circuits is configured to convert the signal from the associated one of the plurality of current sensors to a digital measurement signal and provide the digital measurement signal to the communication bus, and a controller configured to receive the digital measurement signal from each sensor circuit over the communication bus and transmit data related to the digital measurement signal from each sensor circuit to an external client.

Abstract: According to one aspect, embodiments of the invention provide a system for monitoring a plurality of circuit branches coupled to an input line, the system comprising a communication bus, a plurality of sensor circuits, each configured to be coupled to the communication bus and at least one of the plurality of circuit branches, wherein each sensor circuit is further configured to sample current in the at least one of the plurality of circuit branches, a controller configured to be coupled to the communication bus and the input line; wherein the controller is further configured to sample voltage on the input line, and wherein the controller is further configured to synchronize, via the communication bus, current sampling performed by the plurality of sensor circuits with the voltage sampling performed by the controller.

Abstract: A set of current measurements may be transmitted from a remote Intelligent Electronic Device (IED) to a local IED. The current measurements may comprise a timestamp and/or be associated with timestamp information to allow the local IED to time align the local current measurement with the remote current measurement. The local IED may detect a fault within the power system segment defined by the local and remote IEDs by comparing an operating current to a scaled restraint current. A fault may also be detected by comparing the operating current to a scaled nominal current. The operating and restraint currents may be derived from the local and remote current measurements. The restraint current scale may be derived from the characteristics of the local and/or remote IED. The current measurements may correspond to a negative-sequence component and/or a zero-sequence component of a three-phase current measurement set.

Abstract: A system for the detection of welded contacts in a circuit of a line converter system has a plurality of inverter switches, a plurality of utility switches in which a pair of utility switches is connected in series through a line to a utility, a voltage detector, an electronic controller, and a DC input source. The line converter system converts incoming DC power into AC output power that is delivered to the utility grid. The voltage detector measures the voltage across a first node and a second node of the circuit and provides an output that is interpreted by an electronic controller for each step performed during a method of detection of welded contacts. The detection method has a sequence of test steps in which at least one switch is opened and/or closed, a DC bus of the inverter or the utility grid is used as a stimulus voltage, and the voltage is measured.

Abstract: A method for quasi-static testing a magnetic recording head read sensor is described. The method includes applying a first voltage to a heater in the magnetic recording head and measuring an output of the magnetic recording head read sensor while applying the first voltage to the heater and recording the measured output as a first set of measurements. The method further includes applying a second voltage to the heater in the magnetic recording head and measuring the output of the magnetic recording head read sensor while applying the second voltage to the heater and recording the measured output as a second set of measurements. The first and second sets of measurements are then compared.

Abstract: A battery system for vehicle comprises a battery unit that is constituted with a plurality of serially connected cell groups each include a plurality of serially connected battery cells, integrated circuits that are each disposed in correspondence to one of the cell groups of the battery unit and each measure terminal voltages at the battery cells in the corresponding cell group, and a signal transmission path through which one of the integrated circuits is connected to another one of the integrated circuits or to a circuit other than that of the integrated circuits.

Abstract: Disclosed are various embodiments for monitoring power usage. A plurality of power usage cycles are monitored using a controller. Each of the power usage cycles includes a plurality of current draw periods. Each of the current draw periods has a different average current draw. A current draw reading is determined to be abnormal when the current draw reading meets a threshold associated with one of the current draw periods, while the one of the current draw periods is predicted to be active. An action is performed when the current draw reading is determined to be abnormal.

Abstract: A display apparatus and a method for detecting a voltage error thereof, include a display unit which displays an image, a voltage supply which supplies a voltage to respective elements of the display apparatus, a detector which monitors a plurality of voltages supplied to the respective elements of the display apparatus and detects an error occurring from at least one of the plurality of voltages, and a controller which determines a location where an error has occurred if the error has occurred from at least one of the plurality of voltages according to a detection result of the detector. Thus, the display apparatus and method thereof determine whether a voltage error is present and determine the location of one or more errors without difficulty using a circuit for performing the self diagnosis.

Abstract: The apparatus is provided with an abnormality determination means for determining abnormality of the apparatus where two different combinations of two electrodes are selected from the three electrodes, an alternating-current voltage is applied to an electrode in one combination by the voltage-applying portion to measure a value of a current flowing to the other electrode via the dielectric body by electrostatic coupling, an alternating-current voltage is applied to an electrode in another combination out of the at least two different combinations by the voltage-applying portion to measure a value of a current flowing to the other electrode via the dielectric body by electrostatic coupling, and an abnormality of the apparatus is determined from the current values measured.

Abstract: A tool for configuring a branch current monitor facilitates mapping the connections of branch circuits to voltage sources in a power distribution panel.

Abstract: A monitoring apparatus includes a detection circuit, a filter circuit, an amplifying circuit, a regulation circuit, a delay and charging circuit, and a driving circuit. The detection circuit receives a video signal, and performs an operation to obtain an image signal from the video signal. The filter circuit obtains an average intensity of a luminance signal corresponding to the image signal. The delay and charging circuit charges an input capacitor when receiving a low level regulated signal from the amplifying circuit. The driving circuit activates an alarm when a charging voltage of the chargeable capacitor exceeds a predetermined value.

Abstract: A test system for testing a unit such as multiple solid oxide fuel cells. The test system includes a thermal test chamber in which a non-contact electrostatic voltage probe is mounted to scan the solid oxide fuel cells. The test system includes a detector coupled to the voltage probe to produce an output signal or display based on the measured voltages. The measured voltages are processed to compute a representative voltage for each fuel cell and to identify any defective fuel cells based on the measured voltages. The test system may be used during manufacture of solid oxide fuel cell stacks for cost effective testing to lower manufacturing costs.

Abstract: A device and method for monitoring the material health of a structure, providing a miniaturized MEMS Kelvin probe within a housing, wherein the Kelvin probe comprises a conductive plate formed of a stable metal and positioned substantially parallel to the structure; a piezoelectric vibrator for vibrating the conductive plate; and an electrical circuit connected to the conductive plate and the structure, wherein the conductive plate and the structure form a capacitor. The device is contained in one small, lightweight package that can be placed at one or more locations of interest. The sensor can be left in-place for continuous monitoring or for active testing at desired intervals, or be brought to the aircraft at desired intervals.

Abstract: The method of detecting the failure of the excitation circuit of a polyphase alternator controlled by a regulator comprises the following steps: a) electrical information (Iexc) is continuously taken from the excitation circuit (1); b) the electrical information taken in step a) is continuously compared with a predetermined threshold value (Iref); c) a logic state (LT) is continuously determined according to the result of the comparison made in step b); and d) if the logic state (LT) determined in step c) persists for a time at least equal to a predetermined delay time (6), an electrical continuity fault of said excitation circuit is signalled. This method is particularly suitable for machines having a rotor equipped with permanent magnets or having a high remanence of the magnetic circuit of the rotor.

Abstract: A voltage detection circuit used to detect a voltage source includes a Zener diode, a thyristor, a first resistor, a second resistor, a first light-emitting diode (LED), and a second LED. A cathode of the Zener diode is connected to the voltage source. An anode of the Zener diode is connected to a control terminal of the thyristor through a first resistor. An anode of the thyristor is connected to the voltage source through a second resistor. The anode of the thyristor is connected to an anode of the first LED. A cathode of the thyristor is connected to a cathode of the first LED. The cathode of the thyristor is connected to an anode of the second LED, and a cathode of the second LED is grounded.

Abstract: A branch circuit monitoring system (BCMS) for monitoring branch circuit currents in one or more electrical circuit panels is described. The system is comprised of a data center server, one or more panel processors, each with one or more collection devices, and one or more current sensors per collection device. The BCMS is designed to be installed entirely inside the panel without the need for a dedicated enclosure or power supply to facilitate ease of installation and low-cost. The BCMS also allows for future upgradability through standard software updates so that the system can be updated or patched easily. The BCMS data center server collects, aggregates, stores, and serves historical branch circuit current data from the panel processors to networked users via a web server to provide visualization of data such as tables, charts, and gauges.

Abstract: An organic light emitting diode display device that includes a first substrate, a second substrate, a sealing material sealing a space between the first and second substrates and applied along an edge of the second substrate, an interconnection disposed inside the sealing material, and a test unit connected to both ends of the interconnection and configured to measure a preset voltage applied to the interconnection and compare the measured voltage with a reference voltage to determine whether a crack occurred in the sealing material or not. Further, the same effect can be obtained by measuring and comparing currents instead of the voltages.

Abstract: In one embodiment, a protection control monitoring device includes a conversion unit sequentially converting analog data corresponding to an amount of electricity of a power system into digital data and outputting the results as a data sequence, a calculation unit sequentially calculating difference data representing a difference between adjacent data in the data sequence and outputting results as a difference data sequence, a data block generation unit dividing each of a plurality of difference data in the difference data sequence into a plurality of partial data, generating data blocks from a plurality of corresponding partial data, and outputting results as a data block sequence, a compression unit losslessly compressing the data block sequence, and a storage unit storing the losslessly compressed data block sequence.

Abstract: Apparatus for detecting faults in the delivery of electrical power to electrical loads, includes a plurality of load electrical connections arranged to deliver electrical power from an electrical power source to each of a plurality of electrical loads, a plurality of electrical switches, each connected to an associated one of the load connections, and a diagnostic device operable to detect a short circuit fault in the apparatus, wherein the diagnostic device is operable to apply a diagnostic procedure to detect a short circuit connection between at least two of the load electrical connections and includes a control logic unit operable to apply to each of the electrical switches in turn a test control signal causing operation of the switch to apply a test electrical signal to each of the load electrical connections in turn; and detector means connected to the load electrical connections and operable, while the test electrical signal is applied in turn to each load electrical connection, to detect whether a cor

Abstract: The invention relates to a method for testing the operation of an electric heating element which is used for heating activated carbon of an activated carbon filter and/or air which is guided through the activated carbon for the regeneration thereof. The heating element has a PTC-characteristic (positive temperature coefficient characteristic). The strength of a current flow through the heating element in a heating phase selected for the operational testing is measured at a point in time or over a time period and is used for the operational testing, in that at least one measured current flow value is compared with a corresponding current flow value to be anticipated during defect-free operation of the heating element, and the heating element is considered to be defective in the event of a deviation which exceeds a predetermined measurement.

Abstract: Current flow at a line frequency may be measured from a source using matched voltage drops in a pair of voltage drop circuits. The voltage drop circuits may each includes a fixed value component, such as a resistor, and an adjustable value component, such as an adjustable current source, coupled in series. The adjustable valued components may be controlled based on differences in voltage drops produced by the voltage drop circuits based on a high-frequency signal, higher in frequency than the line frequency, applied to a control input for each of the adjustable value components.

Abstract: A method includes inductively coupling an electrical sensor to a transmission line associated with a node of an electrical network, and capturing power transmission information associated with the node through the electrical sensor. The method also includes communicating, through an electrical sensing device including the electrical sensor, information associated with a location of a power outage and/or a sub-optimal performance in the node to a processing node and/or a central control node associated with the electrical network.

Abstract: The present invention relates to a tester, its use and a method for testing signal lines of a flight control system for a trimmable horizontal stabilizer (THS) motor of an aircraft. The tester comprises at least one test-relay (52, 54) to be connected with a relay socket of the flight control system, when the signal lines of the flight control system are to be tested, and at least one indicator (60, 70, 80, 90) being electrically connected with the at least one test-relay (52, 54) for indicating whether a voltage being applied to the test-relay (52, 54) is equal to or larger than a predetermined voltage. The method according to the invention comprises the steps of connecting at least one test-relay (52, 54) of a tester (1), in place of the original relay, with the relay socket of the flight control system, applying a voltage to the at least one test-relay (52, 54) and determining whether a voltage being applied to the at least one test-relay (52, 54) is equal to or larger than a predetermined voltage.

Abstract: A method of inspecting a short circuit defect between first wires extending in a first direction and a second direction intersecting the first direction and second wires extending in the first or second direction, the method including inspecting a short circuit defect between the first and second wires by using a potential difference monitored only in the second wires.

Abstract: An apparatus for measuring RMS values of burst-fired currents includes a current sensor having a signal output, an analog-to-digital (A/D) converter coupled to the signal output of the current sensor, a digital processor coupled to an output of the A/D converter, and a digital memory coupled to the digital processor. Code segments stored in the digital memory are executable on the digital processor and implement a process of: a) initially sampling the output of the A/D converter; b) determining from the initial sampling a burst-fired current pattern; c) sampling the output of the A/D converter N times within a burst-fired current pattern to provide N samples; and d) calculating an RMS value from the N samples.

Abstract: A diagnosis device and method of a voltage transformer can include a current transformer disposed at one side of an output port for generating a current variation according to an on/off operation of a power switch element; a first current detector configured to detect a forward direction current from the current transformer; a second current detector configured to detect a reverse direction current from the current transformer; a first voltage transformer configured to transform the forward direction current detected from the first current detector to a forward direction voltage; a second voltage transformer configured to transform the reverse direction current detected from the second current detector to a reverse direction voltage; and a diagnosis portion for comparing the forward direction voltage with the reverse direction voltage to determine whether or not an offset is formed.

Abstract: An isolation monitor is disclosed in which a switchable bias voltage is imposed on a chassis ground. An isolation voltage is measured when a bias voltage is applied. When there are no electrical faults, the isolation voltage swings up and down to known values. When a fault occurs, the isolation voltage will not to swing to the known values, and thus the isolation resistance can be measured and alarm generated if the isolation resistance falls below a threshold value.

Abstract: An inverter is forcibly operated to supply electric power to a motor, thereby performing detection of a current leakage, on condition that a power-on operation is performed, that the motor is stopped, and that determination as to occurrence or non-occurrence of the current leakage has not yet been made even once after the power-on.

Abstract: The present invention provides an apparatus for easily detecting an abnormal status of power generation of a solar cell panel in a solar cell power generation system having the power generation of 1 MW or higher. The present invention provides an abnormality detecting apparatus for a solar cell power generation system including a plurality of solar cell strings each having a plurality of solar cell modules connected to each other in series and a backflow preventing diode connected to a power output terminal of each of the solar cell strings, characterized in that the abnormality detecting apparatus further includes measuring means for measuring a current flowing in the backflow preventing diode; and that the measuring means is supplied with electric power from both terminals of the backflow preventing diode.

Abstract: In the present method of measuring the current of a first current source, the current thereof may be combined with either the current of a second current source, or the current of a third current source. Based on a combination of the current of the first current source and either (a) the current of the second current source or (b) the current of the third current source, a digital output is provided. If this digital output is of a first value, the state of combining the current of the first current source with the current of the second current source becomes in effect. If this digital output is of a second value, the state of combining the current of the first current source with the current of the second current source becomes in effect.

Abstract: This invention relates to non-contact measurement methods and an apparatus for the identification of hazardous contact voltages on energized objects and surfaces. The apparatus includes an electric field sensor structured to sense an electric field and a gain amplifier electrically connected to the electric field sensor to amplify electric signals from the electric field sensor. The apparatus further includes a signal conditioning circuit adapted to process the amplified electric signals and form time-coordinated signals and a digital signal processor adapted to evaluate the time-coordinated signals and provide a user with a status of a contact voltage source by activating an appropriate status indicator.