Switch monitoring device

Abstract

A kind of switch monitoring device for monitoring the switching operation of relay switch contact of relay, the switch monitoring device has the following characteristics: control terminal, the control terminal is used to apply control signal to the relay switch contact for the switching operation of the relay switch contact;Controller for generating excitation signal;And the impedance circuit with signal input and signal output, wherein, the controller is used to apply the excitation signal to the signal input, the impedance circuit is used to convert the excitation signal into switch monitoring signal, and the switch monitoring signal is output by the signal output, for applying to the relay switch contact, the controller is also used to detect the change of signal present in the impedance circuit, and when the signal exists change, the switching operation of the relay switch contact is detected.

Description

[0001] This application is a divisional application of patent application No. 201980035597.4, filed on May 27, 2019, entitled "Switch Monitoring Device". Technical Field

[0002] This invention relates to a switch monitoring device for monitoring the switch operation of relay switch contacts. Background Technology

[0003] In electrical automation, each actuator can be switched on and off by a relay. It may be necessary to detect the actual switching operation of the relay switch contacts. In such detection, feedback is often obtained by switching the relay on and off using other auxiliary contacts. Alternatively, forced contact control can be implemented to prevent erroneous relay switching operations. When a relay switch contact fails, for example, due to defects in a soldered button, forced contact control can prevent the switching operation of other relay switch contacts and / or the connection of soldered buttons to other buttons. Forced contact control and / or feedback via auxiliary contacts have the disadvantage of increasing production costs in relay manufacturing. Summary of the Invention

[0004] The purpose of this invention is to provide a more effective switch monitoring device that provides information related to the switch state of relay switch contacts, particularly the switch state based on relay control.

[0005] This objective is achieved by the technical features of the independent claims. Advantageous embodiments of the invention are those described in the dependent claims, the specification, and the drawings.

[0006] This invention is based on the understanding that the aforementioned objective can be achieved by a switch monitoring device for applying a switch monitoring signal, particularly a switch monitoring signal in the form of high-frequency auxiliary energy, to a relay switch contact via a signal generator and a transmitter connected downstream of the signal generator. The switch monitoring signal is generated by the signal generator and connected to the load circuit of the relay by the transmitter. Impedance changes in the load circuit, particularly those caused by the switching operation of the relay switch contact, are fed back to the signal generator via the transmitter, resulting in a signal change between the signal generator and the transmitter that can be used to detect the switching operation of the relay switch contact.

[0007] According to a first aspect, the present invention relates to a switch monitoring device for monitoring the switching operation of a relay switch contact. The switch monitoring device includes a controller for generating an excitation signal and a control terminal for applying a control signal to the relay switch contact to perform a switching operation on the relay switch contact.

[0008] The switch monitoring device further includes an impedance circuit with a signal input terminal and a signal output terminal, wherein the controller is used to apply the excitation signal to the signal input terminal. The impedance circuit is used to convert the excitation signal into a switch monitoring signal and output the switch monitoring signal through the signal output terminal for application to the relay switch contacts.

[0009] The controller is also used to detect changes in the signal present in the impedance circuit, and to detect the switching operation of the relay switch contacts when the signal changes.

[0010] In one embodiment, the signal includes the excitation signal and / or the switch monitoring signal.

[0011] In one embodiment, the controller can be used to detect changes in the excitation signal present within the impedance circuit, and, when such a change in the excitation signal is present, to detect the switching operation of the relay switch contacts. The controller can be used specifically to detect changes in the excitation signal, rather than monitoring changes in the switch monitoring signal. Outside the impedance circuit, the controller may have another signal monitoring circuit for monitoring changes in the switch monitoring signal. This signal monitoring circuit can be used to detect changes in the switch monitoring signal via capacitive or inductive coupling.

[0012] By monitoring the relay switch contacts with the aforementioned switch monitoring device, when the control signal is applied to the relay, switch information related to the transition between a first switching state where the relay switch contacts are not conductive and a second switching state where the relay switch contacts are conductive can be generated. This ensures that the relay is switched on and off under the control of the control signal, and ensures that the relay switch contacts and / or the relay's magnet system are correspondingly free from faults. Thus, when the control signal is applied to the relay and the relay switch contacts cannot switch on or off, it can be determined that the relay has failed. Furthermore, even when the switch signal weakens, the switching operation of the relay can still be detected.

[0013] The advantage of the aforementioned switch monitoring device lies in its ability to clearly detect the switching state of the relay switch contacts, particularly in terms of functional safety according to the IEC 61508 standard. This allows for a wider diagnostic coverage.

[0014] In one embodiment, the relay is used to send a signal within a first frequency range and the switch monitoring signal is within a second frequency range, wherein the frequency of the second frequency range is higher than the frequency of the first frequency range, and the impedance of the impedance circuit in the first frequency range is higher than its impedance in the second frequency range.

[0015] The impedance circuit can form a frequency filter, particularly a bandpass filter, where the impedance for the switch monitoring signal and / or the excitation signal is lower than the impedance for electrical signals of other frequencies. This prevents and / or attenuates the input of electrical signals from voltage sources and / or other signal sources with corresponding power transmission capabilities. For example, the first frequency range may include frequencies from 0Hz to 100Hz, and / or the second frequency range may include frequencies above 10kHz, particularly frequencies in the range of 100kHz to 500kHz. By increasing the impedance within the first frequency range, the current on the output side can be reduced, in particular. Accordingly, by coupling the signal input terminal to the signal output terminal within the first frequency range, the current on the input side can be reduced.

[0016] The impedance circuit may, in particular, have a two-port configuration formed by a 2×2 impedance matrix. The impedance at the signal output terminal for lower frequencies, such as those in the 10Hz–100Hz frequency range, especially 50Hz, may be higher than its impedance for higher frequencies, such as those in the 100kHz–1MHz frequency range, especially 500kHz. For example, the impedance may be 13MΩ at 50Hz and 3kΩ at 500kHz. Thus, a frequency-dependent impedance difference of three to four orders of magnitude can be achieved between the first and second frequency ranges.

[0017] In one embodiment, the controller is used to generate the excitation signal within the second frequency range. The advantage achieved is that, due to the lower impedance within the second frequency range, the impedance circuit can efficiently convert the excitation signal into the switching monitoring signal.

[0018] In one embodiment, the controller includes measurement circuitry for monitoring changes in the excitation signal. This measurement circuitry can be particularly used to detect amplitude changes in the excitation signal, such as voltage amplitude changes and / or current amplitude changes.

[0019] The measurement circuit can also be used to detect frequency deviations of the excitation signal. Furthermore, the measurement circuit may have an analog-to-digital converter and / or a measurement signal amplifier to further process the measurement signal, particularly the current and / or voltage variations of the excitation signal.

[0020] In one embodiment, the controller includes a signal generator for generating the excitation signal. The signal generator can be particularly used to generate the excitation signal in the form of a periodic voltage signal. The excitation signal may, for example, have a rectangular, sawtooth, or sinusoidal waveform. The frequency of the excitation signal can be set to a preset value by the signal generator. Furthermore, the signal generator can be used to generate the excitation signal with a fixed frequency value.

[0021] In one embodiment, the measurement circuit has a current sensor connected between the signal generator and the impedance circuit, wherein the current sensor is used to detect the current between the signal generator and the impedance circuit and provide it as a current measurement value to the controller, and the controller is used to detect changes in the current between the signal generator and the impedance circuit based on the current measurement value.

[0022] The current sensor may be formed of a resistor, particularly an ohmic resistor, capable of measuring the current between the signal generator and the impedance circuit in the form of a measured voltage. The controller may also include a voltage measuring device for detecting the measured voltage.

[0023] In addition, the controller may include a voltage sensor for detecting changes in the voltage amplitude of the excitation signal in order to detect the switching operation of the relay switch contacts.

[0024] In one embodiment, the impedance circuit is used to electrically isolate the relay switch contacts from the signal generator and / or controller. The relay switch contacts may have electrical energy applied thereto. The electrical isolation provided by the impedance circuit prevents this electrical energy from accessing the controller and / or signal generator. This electrical energy may be particularly greater than the electrical energy applied to the impedance circuit by the signal generator.

[0025] In one embodiment, the impedance circuit includes a transformer having a primary winding and a secondary winding, wherein the secondary winding is connected in parallel with the relay switch contacts, and the primary winding is connected to the signal generator.

[0026] The transformer is particularly useful for converting the excitation signal into the switch monitoring signal, wherein the current and / or voltage amplitude of the switch monitoring signal is proportional to the current and / or voltage amplitude of the excitation signal, depending on the ratio of the primary-side coil to the secondary-side coil windings. The primary-side coil and the secondary-side coil can be electromagnetically coupled so that the change in the switch monitoring signal generated by the transformer can be applied to the input side of the excitation signal.

[0027] When the relay switch contact is in the first switch state, the switch monitoring signal does not have a low-impedance connection, so that the current intensity flowing through the secondary coil can be lower than the current intensity in the second switch state.

[0028] The capacitor, connected in parallel with the relay switch contact, can form an oscillation circuit with the secondary coil having a preset resonant frequency. The attenuation effect of this oscillation circuit and the relay switch contact in the second switching state is less than its attenuation effect in the first switching state. Thus, when the oscillation circuit is excited by the signal generator, the oscillation amplitude of the oscillation circuit when the relay switch contact is in the second switching state is greater than the oscillation amplitude when the relay switch contact is in the first switching state. The controller can be used to detect this change in oscillation amplitude using a resistor located between the signal generator and the signal input terminal.

[0029] In one embodiment, a second electromagnetic coil may be disposed on the primary winding of the transformer. This electromagnetic coil is used to detect changes in the excitation signal when the switch monitoring signal changes due to the switching operation of the relay switch contacts. The controller can be used to detect the switching operation of the relay switch contacts by evaluating the induced signal of the second electromagnetic coil. The second electromagnetic coil may be disposed on the ferromagnetic core of the transformer adjacent to the primary winding. In one embodiment, the second electromagnetic coil may at least partially surround the primary winding, and more particularly may be wound around the primary winding.

[0030] In one embodiment, the impedance circuit has a capacitor connected in series with the secondary coil, wherein the capacitor is used to form the reactance of the AC voltage signal applied to the relay switch contacts.

[0031] The impedance circuit can be used, in particular, to periodically switch and monitor the signal applied to the relay switch contacts. In the first switching state, the impedance of the signal output terminal can be measured by the capacitor. In the second switching state, the impedance of the signal output terminal can be less than the impedance of the signal output terminal when the relay switch contacts are in the first switching state. The current flowing through the signal output terminal of the impedance circuit, when the signal output terminal has a lower impedance, can have a greater current intensity than when the signal output terminal has a higher impedance. The impedance circuit can be used to couple the corresponding changes in current intensity to the signal input terminal, such that the current intensity flowing through the signal input terminal increases as the output impedance decreases.

[0032] Furthermore, when the relay switch contact performs a switching operation, the voltage amplitude of the switch monitoring signal may change, and when the voltage amplitude of the switch monitoring signal changes, the current and / or voltage amplitude of the excitation signal may also change.

[0033] The capacitor can also form the reactance of the AC voltage signal generated by the voltage source and applied to the relay switch contacts. Furthermore, the capacitor can be used to reduce power loss at the signal output terminal and / or to reduce leakage current flowing through the signal output terminal when the relay switch contacts are in the first switching state.

[0034] The capacitor can be used to withstand transient 230V AC and / or DC voltages without loss.

[0035] In one embodiment, the capacitor may be formed as a parallel-plate capacitor in the form of conductor traces on a printed circuit board. The characteristics of the capacitor may be determined by the material and / or thickness of the circuit board, such that the distance between two conductor trace segments and / or two conductor surfaces can achieve a defined dielectric strength. The circuit board material may be, in particular, FR4, which is formed from glass fiber fabric, especially a di / tetraepoxy material.

[0036] In one embodiment, the signal input terminal is a bipolar input terminal having a first input connection point and a second input connection point, and the signal output terminal is a bipolar output terminal having a first output connection point and a second output connection point. A first capacitor is disposed between the first output connection point and the first input connection point, and a second capacitor is disposed between the second output connection point and the second input connection point, so as to capacitively couple the switch monitoring signal to the relay switch contact.

[0037] In one embodiment, the impedance circuit has an inductor connected downstream of the first capacitor, wherein the inductor and the first capacitor form an oscillating system between the first output connection point and the first input connection point.

[0038] In one embodiment, the switch monitoring device includes a first decoupling capacitor, a second decoupling capacitor, and a signal monitoring circuit. The first decoupling capacitor is connected to the first output connection point, and the second decoupling capacitor is connected to the second output connection point. Each decoupling capacitor is connected to the signal monitoring circuit and is used to convert the switch monitoring signal into a test signal, and to provide the test signal to the signal monitoring circuit, and / or the signal monitoring circuit is used to detect changes in the test signal, and to detect the switching operation of the relay switch contact when the test signal changes.

[0039] Furthermore, the first decoupling capacitor, the second decoupling capacitor, and / or signal monitoring circuitry may be integrated within the controller. In one embodiment, the impedance circuitry may include the respective decoupling capacitors.

[0040] In one embodiment, the controller may be connected to the control terminal and used to generate a control signal to switch the relay switch contacts, and / or apply the control signal to the control terminal.

[0041] The inductor may be, in particular, an electromagnetic coil having an inductance matched to the capacitance of an upstream capacitor, such that the electromagnetic coil and the capacitor have a minimum total impedance at the resonant frequency. The signal generator may, for example, be used to generate the excitation signal having the resonant frequency.

[0042] In one embodiment, the impedance circuit has another inductor connected downstream of the second output connection point, which, together with the second capacitor, forms another oscillating system between the second output connection point and the second input connection point.

[0043] In one embodiment, the impedance circuit is used to apply a high-frequency auxiliary energy form of the switch monitoring signal, particularly in the range of 10 kHz to 1 MHz, to the relay switch contacts. The excitation signal generated by the signal generator preferably has a frequency of 100 kHz to 500 kHz, and may be, in particular, a square wave clock signal. The frequency of the excitation signal may be fixed and / or preset by the controller. The impedance circuit can be used to convert the excitation signal having a coupling frequency into the switch monitoring signal having that coupling frequency.

[0044] In one embodiment, the controller includes a switch controller for generating a control signal to switch the relay switch contacts and applying a control signal to the magnet system of the relay to achieve the switching of the relay switch contacts.

[0045] The controller can also be used to supply electrical power to the signal generator. The activation of the relay can be associated with the generation of the excitation signal by the signal generator, such that the excitation signal can be generated simultaneously with the activation of the relay, and the switch monitoring signal can be applied to the relay switch contacts.

[0046] In one embodiment, the controller applies the control signal to the signal generator, which generates the excitation signal using the switching signal. The advantage of this is that the same electrical signal used to control the relay can also be fed into the signal generator. This eliminates the need for the signal generator and / or the controller to use different power supplies.

[0047] In one embodiment, the controller can be used, in particular, to detect the current intensity of the switching signal and / or the current intensity of the current flowing through the relay coil of the magnet system, especially with a shunt resistor.

[0048] The typical turn-on delay of the relay switch contact is 1ms to 50ms. Thus, by simultaneously activating the relay and the signal generator with the start signal, the switch monitoring signal is applied to the relay switch contact before it switches between the first and second switch states according to the start signal. Therefore, the signal propagation time of the signal link from the signal generator through the impedance circuit to the relay switch contact can be shorter than the turn-on delay of the relay.

[0049] Furthermore, the signal generator can be used to continue generating the excitation signal after the control signal has faded by a time interval particularly greater than the typical disconnection delay of the relay, in order to detect the switching of the relay switch contacts from the second switch state to the first switch state.

[0050] The switch monitoring device can be used to apply the relay control signal, which is applied to the controller to control the relay, to the signal generator, the impedance circuit, and / or the relay's magnet system, to power the corresponding components. Thus, since the signal generator, impedance circuit, and / or controller can be directly powered by the relay control signal, no additional power supply and / or power supply device is required.

[0051] In one embodiment, the signal generator is used to generate the excitation signal in the form of a periodic clock signal, and the controller is used to detect the time interval between the generation time of the excitation signal and the time when the excitation signal changes, based on the constant period of the excitation signal, to detect the switching delay of the relay switch contact.

[0052] The controller can be used, in particular, to detect several cycles and / or clock cycles of the excitation signal, and, based on the fixed frequency of the excitation signal, to detect the time interval between the generation time of the excitation signal and the switching operation time of the relay switch contact. When the relay switch contact switches, the impedance on the output side may change, and this change will cause the excitation signal to also change. This change in the excitation signal can be detected by the controller using a sensor to determine the switching operation of the relay switch contact, and the end of the time interval between the relay start-up time and the switching operation of the relay switch contact.

[0053] The controller can also be used to control the signal generator before the relay switch contact performs a switching operation. Accordingly, the switch monitoring signal can be applied to the relay switch contact during the opening and / or closing process of the relay switch contact. The switch monitoring signal is preferably cut off when the relay switch contact is in the first switching state or the second switching state. The switch monitoring signal may exist, in particular, only during the switching time period when the relay switch contact switches between the first switching state and the second switching state.

[0054] In one embodiment, the controller has a control output terminal, which provides a status signal at the control output terminal, the status signal being an "activated" status signal when the relay switch contacts are closed, and an "unactivated" status signal when the relay switch contacts are open.

[0055] The advantage achieved is that the status signals of multiple switch monitoring devices can be gathered at the same central point, thereby enabling the switching operation of multiple relays in a non-central manner, especially far from the installation location of the corresponding relay among the multiple relays.

[0056] The control output terminal may also be a mirror image of the error indication contact and / or the relay switch contact. Furthermore, the control output terminal may include analog and / or digital interfaces for transmitting information related to the relay and its switching state.

[0057] In one embodiment, the switch monitoring device includes a first attenuation element, and the signal output terminal has a first output connection point located upstream of the first attenuation element to attenuate high-frequency signals applied to the relay switch contacts by the impedance circuit and / or an electrical load and / or voltage source connected to the relay switch contacts.

[0058] Thus, the advantage achieved is that the performance of the switch monitoring device can be improved in terms of electromagnetic compatibility. The attenuation elements are particularly useful for attenuating the signal amplitude of the switch monitoring signal, thereby reducing electromagnetic radiation of the switch monitoring signal in the vicinity of the switch monitoring device and / or relay.

[0059] In one embodiment, the switch monitoring device includes a second attenuation element, and the signal output terminal has a second output connection point located upstream of the second attenuation element to attenuate high-frequency signals applied by the impedance circuit to the relay switch contact and / or the electrical load and / or voltage source connected to the relay switch contact.

[0060] In one embodiment, each of the first attenuation element and / or the second attenuation element has an inductance, and each inductor forms the minimum required impedance of the switch monitoring signal to prevent the switch monitoring signal from bypassing the electrical load and / or voltage source.

[0061] Thus, the advantage achieved is that the switching of the relay switch contacts between the first and second switching states can be reliably detected even in the presence of low-impedance current sources and / or low-impedance electrical loads. If the impedance of the current path through the current source and electrical load is, for example, lower than the impedance of the capacitor connected in parallel with the relay switch contacts, the switch monitoring signal can flow through the current source and / or electrical load, so that the switching operation of the relay switch contacts will not have the impedance recorded at the signal output, or can only exert a small influence on such impedance.

[0062] To minimize power loss caused by current flowing through the inductors, each inductor is preferably configured to have low resistance. In one embodiment, each inductor is configured to have a total load current flowing through the relay switch contacts and determined by the power of the voltage source and the load impedance applied to the relay switch contacts. The inductors may be shared within the coil core, particularly the magnetic core, and particularly form a current-compensated choke. Furthermore, to maximize the possible push-pull impedance for the switch monitoring signal, the inductors may be nested together, with their winding directions opposite to each other. Attached Figure Description

[0063] Other exemplary embodiments will be described below with reference to the accompanying drawings. In the drawings:

[0064] Figure 1 The image shows a switch monitoring device in one embodiment;

[0065] Figure 2 The image shows a switch monitoring device in one embodiment;

[0066] Figure 3 The image shows a switch monitoring device in one embodiment;

[0067] Figure 4 The figure shows the signal waveform of the relay when it is activated by the switch monitoring device in one embodiment;

[0068] Figure 5 The diagram shows an event sequence when the relay is turned on by the switch monitoring device in one embodiment;

[0069] Figure 6 The diagram shows an event sequence when the relay is disconnected by the switch monitoring device in one embodiment;

[0070] Figure 7 A schematic diagram of a switch monitoring device for monitoring the switching operation of relay switch contacts.

[0071] List of reference numerals

[0072] 100 Switch Monitoring Device

[0073] 101 Relay switch contacts

[0074] 103 Relay

[0075] 105 controller

[0076] 107 impedance circuit

[0077] 109 signal input terminal

[0078] 111 signal output terminal

[0079] 113 signal generator

[0080] 115 Measurement Circuit

[0081] 117 Transformer

[0082] 119-1 Primary side coil

[0083] 119-2 Secondary coil

[0084] 121 Current Sensor

[0085] 123 Capacitor

[0086] 125 Magnet System

[0087] 127 Control Output Terminal

[0088] 129 Electrical loads

[0089] 131 Power Supply

[0090] 133 Control Input Terminal

[0091] 201-1 First Input Port

[0092] 201-2 Second Input Port

[0093] 203-1 First Output Port

[0094] 203-2 Second Output Port

[0095] 205-1 First Capacitor

[0096] 205-2 Second Capacitor

[0097] 207 Inductor

[0098] 301-1 First Attenuation Element

[0099] 301-2 Second Attenuation Element

[0100] 303-1 Inductor

[0101] 303-2 Inductor

[0102] 400 waveform

[0103] 401 Coil Voltage

[0104] 403 Coil Current

[0105] 405 stimulus signal

[0106] 407 Switch Monitoring Signal

[0107] 409 Status Signal

[0108] t1 time point

[0109] t2 time point

[0110] t3 time point

[0111] t4 time point

[0112] t5 time point

[0113] t6 time point

[0114] t7 time point

[0115] t8 time point

[0116] t9 time point

[0117] t10 time point

[0118] Δ1 time interval

[0119] Δ2 time interval

[0120] 500 event sequences

[0121] 501 Connection initiated

[0122] 503 Control Relay

[0123] 505 Clock Open

[0124] 507 Relay completed connection

[0125] 509 Current Change

[0126] 511 Open the runtime determination unit

[0127] 513 Feedback "Initiated"

[0128] 515 call ended

[0129] 600 event sequence

[0130] 601 Start disconnecting

[0131] 603 Turn off relay

[0132] 605 Clock Open

[0133] 607 Relay completed disconnection

[0134] 609 Current Change

[0135] 611 Shutdown Runtime Determination Unit

[0136] 613 feedback "Not starting"

[0137] 615 Disconnection End

[0138] 701 Coupling Capacitor

[0139] 703 Coupling Capacitor

[0140] 705 Signal Monitoring Circuit Detailed Implementation

[0141] Figure 1 This is a schematic diagram of a switch monitoring device 100 for monitoring the switching operation of the relay switch contact 101 of relay 103. The switch monitoring device 100 includes a controller 105, which generates control signals and excitation signals for the switch contact 101 of the relay.

[0142] The switch monitoring device 100 further includes an impedance circuit 107 having a signal input terminal 109 and a signal output terminal 111. The controller 105 is used to apply the excitation signal to the signal input terminal 109. The impedance circuit 107 is used to convert the excitation signal into a switch monitoring signal and output the switch monitoring signal at the signal output terminal 111 for application to the relay switch contact 101.

[0143] Additionally, the controller 105 is used to detect signal changes present in the impedance circuit 107, particularly changes in the excitation signal and / or switch monitoring signal, and to determine the switching operation of the relay switch contact 101 when such signal changes are present.

[0144] Relay 103 is used to send signals within a first frequency range and the switch monitoring signal is within a second frequency range, where the frequencies in the second frequency range are higher than those in the first frequency range. Furthermore, the impedance circuit 107 has a higher impedance in the first frequency range than its impedance in the second frequency range.

[0145] The controller 105 also includes a signal generator 113 for generating the excitation signal within the second frequency range. An impedance circuit 107 is used to electrically isolate the relay switch contact 101 from the signal generator 113 and / or the controller 105.

[0146] The controller 105 also includes a measurement circuit 115 for monitoring changes in the excitation signal. The measurement circuit 115 has a current sensor 121 connected between the signal generator 113 and the impedance circuit 107. The current sensor 121 detects the current between the signal generator 113 and the impedance circuit 107 and provides it as a current measurement value to the controller 105. Furthermore, the controller 105 detects current changes between the signal generator 113 and the impedance circuit 107 based on the current measurement value.

[0147] Impedance circuit 107 includes a transformer 117 having a primary-side coil 119-1 and a secondary-side coil 119-2, wherein the secondary-side coil 119-2 is connected in parallel with the relay switch contact 101, and the primary-side coil 119-1 is connected to a signal generator 113. Furthermore, impedance circuit 107 includes a capacitor 123 connected in series with the secondary-side coil 119-2. Capacitor 123 is used to form reactance for AC voltage signals applied to the relay switch contact 101.

[0148] In addition, impedance circuit 107 is used to apply the switch monitoring signal in the form of high-frequency auxiliary energy, particularly in the range of 10kHz to 1MHz, to the relay switch contact 101.

[0149] In addition, the controller 105 includes a switch controller for generating the control signal for switching the relay switch contact 101, and for applying the control signal to the magnet system 125 of the relay 103 to realize the on / off state of the relay switch contact 101.

[0150] In one embodiment, controller 105 is used to apply the control signal to signal generator 113, and signal generator 113 is used to generate the excitation signal with the switching signal.

[0151] In addition, the signal generator 113 is used to generate the excitation signal in the form of a periodic clock signal, and the controller 105 is used to detect the time interval between the generation time of the excitation signal and the time when the excitation signal changes, based on the constant period of the excitation signal, in order to detect the switching delay of the relay switch contact 101.

[0152] The controller 105 also includes a control output terminal 127, and the controller 105 is used to provide a status signal to the control output terminal 127, which is "started" when the relay switch contact 101 is closed, and "not started" when the relay switch contact 101 is open.

[0153] The controller 105 also includes a control input 133 through which the controller 105 can obtain a power supply. The controller 105 is particularly suitable for receiving electrical energy in the form of DC voltage in the range of 3V to 24V.

[0154] Figure 2 This is a schematic diagram of a switch monitoring device 100 that monitors the switching operation of the relay switch contact 101 of a relay 103 in one embodiment. The signal input terminal 109 is a bipolar input terminal with a first input connection point 201-1 and a second input connection point 201-2, and the signal output terminal 111 is a bipolar output terminal with a first output connection point 203-1 and a second output connection point 203-2. Furthermore, a first capacitor 205-1 is disposed between the first output connection point 203-1 and the first input connection point 201-1, and a second capacitor 205-2 is disposed between the second output connection point 203-2 and the second input connection point 201-2, to couple the switch monitoring signal to the relay switch contact 101.

[0155] In addition, the impedance circuit 107 includes an inductor 207 connected downstream of the first capacitor 205-1, wherein the inductor 207 and the first capacitor 205-1 form an oscillation system between the first output connection point 203-1 and the first input connection point 201-1.

[0156] Figure 3 According to Figure 1The schematic diagram shows a switch monitoring device 100 that monitors the switching operation of the relay switch contact 101 of the relay 103 according to the embodiment shown.

[0157] The switch monitoring device 100 further includes a first attenuation element 301-1 and a second attenuation element 301-2. The signal output terminal 111 has a first output connection point 203-1 and a second output connection point 203-2, wherein the first attenuation element 301-1 is connected downstream of the first output connection point 203-1, and the second attenuation element 301-2 is connected downstream of the second output connection point 203-2, so as to absorb the high-frequency signal applied to the relay switch contact 101 by the impedance circuit 107 and / or the electrical load 129 and / or the voltage source 131 connected to the relay switch contact 101.

[0158] Each of the first attenuation element 301-1 and the second attenuation element 301-2 has an inductor 303-1, 303-2 that forms the minimum required impedance of the switch monitoring signal to prevent the switch monitoring signal from bypassing the electrical load 129 and / or the voltage source 131.

[0159] Figure 4 This is a schematic diagram of the signal waveform 400 when the relay is activated by the aforementioned switch monitoring device. At a first time point t1, a relay control signal is applied to the electromagnetic relay coil of the relay's magnet system. Correspondingly, a coil voltage 401 is applied to the electromagnetic relay coil. When the coil voltage 401 is applied to the electromagnetic relay coil, the coil current 403 within the electromagnetic relay coil increases.

[0160] Furthermore, starting from time point t1, the signal generator of the switch monitoring device generates an excitation signal 405 in the form of a square wave signal, specifically having only a positive signal amplitude. Under the action of the impedance circuit, the excitation signal 405 is converted into a switch monitoring signal 407, and this switch monitoring signal is applied to the relay switch contacts. Starting from time point t2, the switch monitoring signal 407 has the signal waveform of the excitation signal 405.

[0161] Before time point t2, the relay switch contacts are in a first switching state and are correspondingly non-conductive or have high resistance. The total resistance detectable at the bipolar signal output of the impedance circuit can be determined by an external circuit consisting of an electrical load and / or voltage source. Furthermore, in one embodiment, the attenuation element is particularly in the form of an inductor and can be a contributing factor to the total resistance. Based on the total resistance, the current sensor can detect the current between the signal generator and the impedance circuit.

[0162] From time point t2, the relay switch contact switches from the first switch state to the second switch state, where the time interval between t2 and t3 determines the bounce time of the relay switch contact. When the relay switch contact switches, the switch monitoring signal 407 is disconnected in the form of a voltage across the relay switch contact. Accordingly, since the impedance of the capacitor connected in parallel with the relay switch contact is less than the impedance of the non-conductive relay switch contact, the total resistance at the signal output of the impedance circuit also changes. This change in total resistance can cause a change in the signal at the signal input or the primary side signal of the signal generator, and this change can be, for example, a change in the current amplitude detectable by the current sensor.

[0163] The controller is used to detect the switching operation of the relay switch contacts at time t2 by detecting the current change at time t2. The controller can also be used to correspondingly cut off the excitation signal 405 at time t5 by disconnecting the signal generator. Alternatively, the controller can also be used to continuously generate the excitation signal 405 to continuously apply a switching monitoring signal 407 to the relay switch contacts. The excitation signal 405 can be generated, particularly within the time interval Δ2 between time t5 and time t7.

[0164] In one embodiment, the controller is used to periodically control the signal generator to repeatedly generate an excitation signal 405 at a certain period and to detect the switching state of the relay switch contacts. Accordingly, the controller can be used to detect whether the relay switch contacts are in the first switching state or the second switching state by measuring the absolute amplitude value and / or effective amplitude value of the excitation signal 405. Accordingly, by periodically checking the relay switch contacts with the switch monitoring device, it can, for example, be ensured that the relay switch contacts are in a conductive state.

[0165] When the relay switch contact switches to the second switch state, the controller generates feedback on the switching operation of the relay switch contact by generating a status signal 409 at the control output terminal.

[0166] At time t7, by disconnecting the relay control signal, the relay switch contacts can be switched from the second switch state to the first switch state, thereby disconnecting the relay. From time t7, an excitation signal 405 can be generated by turning on the signal generator, and a switch monitoring signal 407 can be applied to the relay switch contacts accordingly. The signal generator can be turned off at time t10.

[0167] Starting from time point t8, the relay switch contacts begin to open, thereby disconnecting the electrical connection through the relay switch contacts. Starting from time point t9, the switch contacts are completely open and no longer conduct electricity. Starting from time point t9, the electric arc between the open contacts of the relay switch can be extinguished.

[0168] For each switching operation, the time interval t2-t3 during which the relay switch contacts bounce back and the time interval t8-t9 during which the relay switch contacts generate an arc can be different. The signal generator remains on outside of these time intervals to detect the time deviation of each time interval and / or the entire on / off process of the relay switch contacts.

[0169] The controller can also be used to determine the number of bounces and / or the bounce time based on the signal curve of the excitation signal 405 and the signal curve of the switch monitoring signal 407. Furthermore, the controller can be used to compare the determined bounce time and / or the determined number of bounces with corresponding limits.

[0170] The controller can also be used to detect the coil current 403 and determine the armature impact time point t6 based on the time amplitude curve of the coil current 403 when the switch signal is applied to the electromagnetic relay coil. The armature impact time point t6 can be defined as the point at which the magnet system deflects the relay armature to its maximum extent and the working air gap between the relay's yoke and the armature has been completely overcome. Furthermore, at the armature impact time point t6, the mechanical contact between the buttons of the relay switch contacts corresponds to the maximum possible pressure. The controller can be used to determine the time point t2 when the relay switch contacts begin to conduct electricity and the armature impact time point t6.

[0171] Furthermore, the controller can also be used to determine the time interval Δ1 between time points t2 and t6. Based on the signal curves of the excitation signal 405, the switch monitoring signal 407, and / or the coil current 403 within the time interval Δ1, the controller can be used to determine typical relay parameters. Additionally, the controller can be used to determine the typical relay parameters continuously or at periodic intervals to determine the wear condition, failure probability, and / or maintenance or replacement time of the relay based on the time curves of these relay parameters. The controller can also be used to detect the switching cycle of the relay.

[0172] Furthermore, the controller can be used to switch the status signal 409 to "started" at time point t4, thereby increasing the signal amplitude of the status signal 409 accordingly. Additionally, the controller can be used to switch the status signal 409 to "not started" at time point t8, thereby decreasing the signal amplitude of the status signal 409 accordingly.

[0173] Figure 5The diagram illustrates a relay energizing event sequence 500 implemented by the switch monitoring device in one embodiment. In event sequence 500, energizing 501 occurs first, characterized by the presence of a relay control signal at the control input of the controller. Subsequently, the controller applies the activation signal to the magnet system of the relay to activate the relay 503. Afterward, the signal generator is activated to generate a clock signal; this event is represented as "clock on" 505. Following the relay's energizing delay, the relay switch contacts close, thereby completing the relay energizing 507.

[0174] When the relay switch contact is closed, the current flowing through the relay switch contact changes, and the current flowing through the signal output terminal of the impedance circuit changes accordingly, resulting in a current change 509 on the input side. By activating the transit time determination unit 511, the controller can determine and record the closing time of the relay switch contact.

[0175] Subsequently, the controller switches the feedback to the "activated" state 513 by switching the status signal 409 at the control output terminal to "activated". This completes the activation of the relay, and the event sequence 500 ends 515.

[0176] Figure 6 The diagram illustrates a relay disconnection event sequence 600 implemented by the switch monitoring device in one embodiment. In event sequence 600, disconnection 601 occurs first, characterized by the absence of a relay control signal at the control input of the controller. Accordingly, the control signal is not applied to the relay's magnet system. Subsequently, the signal generator is turned on to generate a clock signal; this event is represented as "clock on" 605. After the relay disconnection delay, the relay switch contacts open, thereby completing the relay disconnection 507.

[0177] When the relay switch contact is open, the current flowing through the relay switch contact changes, and the current flowing through the signal output terminal of the impedance circuit changes accordingly, resulting in a current change 609 on the input side. By shutting down the running time determination unit 611, the controller can detect the disconnection time to determine the running time of the relay based on the difference between the connection time and the disconnection time.

[0178] Subsequently, the controller switches the feedback to the "non-start" state 613 by switching the status signal 409 at the control output terminal to "non-start". This completes the disconnection of the relay, and the event sequence 600 ends 615.

[0179] Figure 7This is a schematic diagram of a switch monitoring device 100 for monitoring the switching operation of the relay switch contact 101 of relay 103. The switch monitoring device 100 also includes two coupling capacitors 701 and 703 and a signal monitoring circuit 705. Capacitors 701 and 703 are connected to a signal output terminal 111 on the input side and to the signal monitoring circuit 705 on the output side. Furthermore, the coupling capacitors 701 and 703 are used to capacitively couple the signal applied to the relay switch contact, particularly the switch monitoring signal, to the signal monitoring circuit 705.

[0180] Thus, the advantage achieved is that the impedance circuit 107 can inductively couple the switch monitoring signal to the relay switch contact 101, and changes in the switch monitoring signal can be detected capacitively by the coupling capacitors 701 and 703 and provided to the signal monitoring circuit 705. The signal monitoring circuit 705 can be used to detect changes in the switch monitoring signal and provide the status signal. Furthermore, the coupling capacitors 701 and 703 and / or the signal monitoring circuit 705 can be part of the controller 105 and / or integrated therein.

Claims

1. A switch monitoring device (100) for monitoring the switching operation of the relay switch contacts (101) of a relay (103), characterized in that, The switch monitoring device (100) has the following characteristics: Control terminal (102), the control terminal is used to apply a control signal to the relay switch contact (101) to perform a switching operation on the relay switch contact (101). A controller (105) for generating excitation signals; and An impedance circuit (107) has a signal input terminal (109) and a signal output terminal (111), wherein the controller (105) is used to apply the excitation signal to the signal input terminal (109), wherein the impedance circuit (107) is used to convert the excitation signal into a switch monitoring signal and output the switch monitoring signal at the signal output terminal (111) for application to the relay switch contact (101), wherein the controller (105) is also used to detect changes in the signal present in the impedance circuit (107), and when the signal changes, detect the switching operation of the relay switch contact (101). The signal input terminal (109) is a bipolar input terminal with a first input connection point (201-1) and a second input connection point (201-2), and the signal output terminal (111) is a bipolar output terminal with a first output connection point (203-1) and a second output connection point (203-2). A first capacitor (205-1) is provided between the first output connection point (203-1) and the first input connection point (201-1), and a second capacitor (205-2) is provided between the second output connection point (203-2) and the second input connection point (201-2) to capacitively couple the switch monitoring signal to the relay switch contact (101).

2. The switch monitoring device (100) according to claim 1, characterized in that, The impedance circuit (107) has an inductor (207) connected downstream of the first capacitor (205-1), wherein the inductor (207) and the first capacitor (205-1) form an oscillating system between the first output connection point (203-1) and the first input connection point (201-1).

3. The switch monitoring device (100) according to claim 1 or 2, characterized in that, The impedance circuit (107) has another inductor connected downstream of the second output connection point (203-2), which, together with the second capacitor (205-2), forms another oscillation system between the second output connection point (203-2) and the second input connection point (201-2).

4. The switch monitoring device (100) according to claim 1, characterized in that, The signals present in the impedance circuit (107) include the excitation signal and / or the switch monitoring signal.

5. The switch monitoring device (100) according to claim 1, characterized in that, The relay (103) is used to send a signal within a first frequency range, and the switch monitoring signal is within a second frequency range, wherein the frequency of the second frequency range is higher than the frequency of the first frequency range, and the impedance circuit (107) has a higher impedance in the first frequency range than in the second frequency range.

6. The switch monitoring device (100) according to claim 5, characterized in that, The controller (105) is used to generate the excitation signal within the second frequency range.

7. The switch monitoring device (100) according to claim 1, characterized in that, The controller (105) includes a measurement circuit (115) for monitoring the changes in the excitation signal.

8. The switch monitoring device (100) according to claim 7, characterized in that, The controller (105) includes a signal generator (113) for generating the excitation signal.

9. The switch monitoring device (100) according to claim 8, characterized in that, The measurement circuit (115) has a current sensor (121) connected between the signal generator (113) and the impedance circuit (107), wherein the current sensor (121) is used to detect the current between the signal generator (113) and the impedance circuit (107) and provide the current as a current measurement value to the controller (105), wherein the controller (105) is used to detect the change of the current between the signal generator (113) and the impedance circuit (107) based on the current measurement value.

10. The switch monitoring device (100) according to claim 8, characterized in that, The impedance circuit (107) is used to electrically isolate the relay switch contact (101) from the signal generator (113) and / or the controller (105).

11. The switch monitoring device (100) according to claim 8, characterized in that, The controller (105) is connected to the control terminal (102) and is used to generate a control signal to perform a switching operation on the relay switch contact (101) and / or apply the control signal to the control terminal (102).

12. The switch monitoring device (100) according to claim 11, characterized in that, The controller (105) includes a switch controller, which generates a control signal for switching the relay switch contact (101) and applies the control signal to the magnet system (125) of the relay (103) to achieve the switching of the relay switch contact (101).

13. The switch monitoring device (100) according to claim 11 or 12, characterized in that, The controller (105) is used to apply the control signal to the signal generator (113), wherein the signal generator (113) is used to generate the excitation signal as a switching signal.

14. The switch monitoring device (100) according to claim 11 or 12, characterized in that, The signal generator (113) is used to generate the excitation signal in the form of a periodic clock signal, wherein the controller (105) is used to detect the time interval between the generation time of the excitation signal and the time when the impedance of the signal output terminal (111) changes, according to the constant period of the excitation signal, so as to detect the switching delay of the relay switch contact (101).

15. The switch monitoring device (100) according to claim 1, characterized in that, The controller (105) has a control output terminal (127), wherein the controller (105) is used to provide a status signal at the control output terminal (127), the status signal being "started" after the relay switch contact (101) is turned on, and "not started" after the relay switch contact (101) is turned off.

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