CN107271896A - Safety relay test device and its method of testing - Google Patents

Abstract

The invention provides a safety relay testing device and a testing method thereof, wherein the safety relay testing device includes an MCU controller, a relay contact testing module, a relay coil testing module, a power supply protection control unit, and a key input circuit; , the coil resistance measurement/stuck test switching circuit is controlled by the MCU controller to perform coil resistance measurement and stuck test switching; when performing coil resistance and contact resistance measurement, the MCU controller according to the coil resistance and The contact resistance draws the action characteristic diagram of the relay; when performing the sticking test, input and set the coil power supply voltage, test times, test pull-in time and test interval time through the key input circuit. The invention has scientific design, strong practicability, and can carry out automatic testing and repeated testing of the safety relay testing device.

Description

Safety relay testing device and testing method thereof

technical field

The invention relates to the field of safety relays, in particular to a safety relay testing device and a testing method thereof.

Background technique

The safety relay is installed on the internal relay control board of the platform controller (PEDC), and is mainly used to execute action signals such as permission, opening, closing, interlocking, and locking of the screen door, and control the door head DCU to open and close the screen door. At present, there are two kinds of safety relays commonly used in the subway screen door system, which are German Hensler and Japanese Panasonic. The failure rate of the subway screen door platform controller (PEDC) is high. During the maintenance process, it was found that the safety relay on the PEDC internal relay control board had a high failure rate, which seriously affected the operation of the main line.

The structure of the safety relay has disadvantages: the mechanical structure is complex, the weight is large, and the contact size is long, which is prone to fatigue; the contacts and coils are not sealed, and dust is easy to enter. After a long period of use, the contacts will be damaged by ignition. Due to the high purchase price of the relay and the long procurement cycle, when a fault occurs, in order to quickly troubleshoot the fault, emergency fault handling is carried out on the safety relay, such as repairing the relay contacts, grinding, cleaning and reinstalling the relay contacts, or replacing Contacts with severe damage.

In the absence of test equipment during the maintenance process, the relay can only be tested manually by conventional methods. As a result, the fault diagnosis test of the relay takes a long time, and the maintenance personnel perform repetitive operations, which affects the maintenance efficiency. There are also some test devices, such as: Patent Application No. 201610847392.4 "Test Device and Test Method for Safety Relay", which provides a test device and test method for safety relays. By changing the voltage provided by the relay coil, observe with eyes The light-emitting diode corresponding to the contact state is used to determine whether the working state of the relay contact is normal. When measuring the contact resistance, use the knob to select the switch, connect the contacts of the relay to the corresponding light-emitting diodes with the resistance meter respectively, and read the resistance value of the connected contact resistance through the resistance meter. Patent Application No. 201620684412.6 "Testing Device for Subway Signal Safety Relay and Vehicle Relay", uses an oscillating circuit to generate a level-reversal signal output with a frequency that can be set, and is used to drive the coil of the relay. In this way, the control of the frequency of power-on and power-off of the relay is realized, and the counter records the number of times it has been run.

The conventional method uses an adjustable DC regulated power supply and a multimeter for relay testing. Use the ohm gear of the multimeter or the resistance meter to measure the resistance value of the relay coil or contact, and judge whether the relay is good or bad by loading different voltage values on the relay coil and measuring the opening and closing action of the relay contact. The operation of this test method is cumbersome and complicated, and different data points need to be measured manually. The operation is cumbersome, and the error and influence caused by human factors are relatively large.

In order to solve the above existing problems, people have been seeking an ideal technical solution.

Contents of the invention

The object of the present invention is to address the deficiencies in the prior art, and provide a safety relay testing device with scientific design, strong practicability, and automatic testing and repeated testing. The present invention also provides a testing method for the safety relay testing device.

In order to achieve the above object, the technical solution adopted in the present invention is: a safety relay testing device, including an MCU controller, a relay contact testing module, a relay coil testing module, a power supply protection control unit, and a button input circuit; the power supply includes The control unit includes a power input protection control circuit, a DC-DC step-down circuit, and a DC-DC digital control boost module. The input end of the power input protection control circuit is connected to the mains; A power protection isolation circuit and the first AC-DC switching power supply are connected to the output end of the power input protection control circuit for providing 12V-120V voltage; the DC-DC step-down circuit is sequentially passed through the second power protection isolation circuit and the second AC-DC switching power supply is connected to the output end of the power input protection control circuit for providing 12V-5V voltage; the relay contact test module includes a relay contact measurement board and a first ADC acquisition circuit, The relay contact measurement board is connected to the contact of the relay to be tested in a four-wire measurement mode, and is connected to the MCU controller through the first ADC acquisition circuit; the relay coil test module includes a coil resistance measurement/card Hysteresis test switching circuit, coil resistance measurement board and second ADC acquisition circuit; the coil resistance measurement/stuck test switching circuit is connected to the relay coil to be tested in a four-wire measurement mode, connected to the coil resistance measurement board, It is also connected to the DC-DC numerically controlled step-up module through the voltage and current acquisition circuit and the electronic switch in turn; the electronic switch is connected to the MCU controller through the IO isolation drive circuit; the MCU controller is connected to the second ADC through the The acquisition circuit is connected to the voltage and current acquisition circuit and the coil resistance measurement board, and is connected to the coil resistance measurement/stuck test switching circuit through the switch state feedback circuit; the button input circuit is connected to the MCU controller , to set test parameters.

Based on the above, a safety relay test seat is also included, and the safety relay test seat is provided with ten relay contact measurement boards, two coil resistance measurement boards, an RS485 serial interface, and a USB interface.

Based on the above, the MCU controller is also connected with a temperature and humidity sensor for collecting the temperature and humidity of the test environment, an SD card for storing test data, and an indicator light for indicating the status of the safety relay test socket.

Based on the above, the relay contact measurement board includes a low-end drive constant current source circuit, a high-end drive constant current source circuit, a filter circuit, an output reverse current protection circuit, a contact test interface, and a first-stage input protection circuit connected in sequence. , a first-level signal buffer circuit, a first-level input signal filter circuit, a second signal buffer circuit, a second-level input signal filter circuit, and an output-level protection circuit, the first-level input protection circuit is connected to the contact test interface of the relay , the output end of the output stage protection circuit is a voltage feedback signal interface.

Based on the above, the relay contact measurement board is also provided with a contact resistance comparison circuit for indicating normal or abnormal contact resistance during the sticking test, and the comparison voltage of the contact resistance comparison circuit is taken from the The output of the first stage input signal filtering circuit.

Based on the above, the coil resistance measurement board includes a sequentially connected reference voltage source, a precision resistance network, a gear switching circuit, a low-end drive constant current source circuit, a high-end drive constant current source circuit, a filter circuit, and an output reverse current protection circuit. , coil test interface, first-level input protection circuit, first-level signal buffer circuit, first-level input signal filter circuit, second signal buffer circuit, second-level input signal filter circuit, output-level protection circuit; the gear position The switching circuit is connected to the MCU controller through the gear switching control circuit, the first-level input protection circuit is connected to the contact test interface of the relay, and the output terminal of the output-level protection circuit is a voltage feedback signal interface.

A testing method of the safety relay testing device, wherein the coil resistance measurement/stuck test switching circuit is controlled by the MCU controller to perform coil resistance measurement and stuck test switching; when coil resistance and contact resistance are measured, The MCU controller controls the conduction or disconnection of the electronic switch to supply power to the relay connected to the power supply circuit; the DC-DC digital control step-up module outputs different voltages manually or program-controlled, and the coil resistance measurement The board measures the coil resistance under different voltages, and uploads it to the MCU controller after analog-to-digital conversion by the second ADC acquisition circuit. The relay contact measurement board measures the contact resistance under different voltages. The first ADC acquisition circuit is uploaded to the MCU controller after analog-to-digital conversion; the MCU controller draws the action characteristic diagram of the relay according to the coil resistance and the contact resistance; The button input circuit inputs and sets the coil power supply voltage, the number of tests, the test pull-in time and the test interval time; the DC-DC numerical control step-up module program-controlled output sets the coil power supply voltage, and the voltage and current acquisition circuit collects the coil power supply voltage under the current voltage The line current value is uploaded to the MCU controller after analog-to-digital conversion by the second ADC acquisition circuit, the MCU controller calculates the current coil resistance, and the relay contact measurement board measures the set coil voltage The contact resistance is uploaded to the MCU controller after analog-to-digital conversion by the first ADC acquisition circuit.

Compared with the prior art, the present invention has outstanding substantive features and significant progress, specifically:

1. By program-controlling the constant current value of three fixed gears (1mA, 10mA, 100mA), it can automatically judge the resistance range of the coil resistance, automatically switch the constant current value, and can automatically test and repeatedly test the coil resistance of the relay.

2. By program-controlling the constant current value (0-100mA) loaded on the contacts, it can automatically test and repeatedly test the resistance of each group of contacts of the relay.

3. The device is designed with 10-way contact resistance measurement board interface and 2-way coil resistance measurement board interface. The idea of modular design is adopted for the measurement of coil resistance and contact resistance. Simultaneous and real-time measurement of all contact states of various types of relays can be realized by increasing the types and quantities of measurement boards.

4. The measurement of coil resistance and contact resistance is driven by a constant current source, and the measurement method of four-wire wiring is used for the measured coil or contact, which avoids the influence of the measuring wire and the relay test base on the measured resistance. influences.

5. The coil power supply voltage of the test relay can be adjusted manually or by program control, the output voltage is adjustable (DC12-120V), and the action characteristics of the relay can be drawn automatically through real-time collection of contact resistance.

6. Able to carry out the sticking test of the relay. While testing the contact resistance, through the contact resistance comparison circuit, the settable reference voltage value is used as the reference resistance comparison threshold, and the contact resistance resistance and the same settable reference voltage value constitute a comparison circuit, and the hardware Output the level indication of the resistance value of each group of contacts and the reference resistance value, and then send the high and low level signals to the MCU, the green light will be on when the test is normal, and the buzzer will alarm and the red light will flash if the test is abnormal; if the test is abnormal, the number of tests that will automatically stop is reached , it means that the relay is stuck, the buzzer will alarm and the red light will flash, and the test will stop automatically.

7. The measured data of coil resistance and contact resistance can be communicated with the upper computer software of PC through RS485 communication, and the test data can be displayed, recorded and analyzed in real time. At the same time, it can be stored in the SD card, which is convenient for off-line measurement of the relay state, and can be analyzed by reading the data of the SD card.

Description of drawings

Fig. 1 is a structural block diagram of the present invention.

Fig. 2 is a circuit frame diagram of the safety relay test socket of the present invention.

Fig. 3 is a block diagram of the relay coil testing module of the present invention.

Fig. 4 is a block diagram of the relay contact testing module of the present invention.

Fig. 5 is a circuit diagram of the relay coil testing module of the present invention.

Fig. 6 is a circuit diagram of the relay contact testing module of the present invention.

detailed description

The technical solutions of the present invention will be described in further detail below through specific implementation methods.

As shown in Figures 1-4, a safety relay test device includes an MCU controller, a relay contact test module, a relay coil test module, a power protection control unit, and a key input circuit; the power supply includes a control unit including a power input protection Control circuit, DC-DC step-down circuit, DC-DC numerical control boost module, the input terminal of the power input protection control circuit is connected to the mains; the DC-DC numerical control boost module is sequentially passed through the first power supply protection isolation circuit and The first AC-DC switching power supply is connected to the output terminal of the power supply input protection control circuit for providing 12V-120V voltage; the DC-DC step-down circuit is sequentially passed through the second power supply protection isolation circuit and the second AC-DC The switching power supply is connected to the output end of the power input protection control circuit for providing 12V-5V voltage; the relay contact test module includes a relay contact measurement board and a first ADC acquisition circuit, and the relay contact measurement The board is connected to the contacts of the relay to be tested in a four-wire measurement mode, and is connected to the MCU controller through the first ADC acquisition circuit; the relay coil test module includes a coil resistance measurement/stuck test switching circuit, a coil The resistance measurement board and the second ADC acquisition circuit; the coil resistance measurement/stuck test switching circuit is connected to the relay coil to be tested in a four-wire measurement mode, connected to the coil resistance measurement board, and sequentially through the voltage and current acquisition The circuit and the electronic switch are connected to the DC-DC numerically controlled step-up module; the electronic switch is connected to the MCU controller through an IO isolation drive circuit; the MCU controller is connected to the voltage through the second ADC acquisition circuit The current acquisition circuit and the coil resistance measurement board are connected to the coil resistance measurement/stuck test switching circuit through the switch state feedback circuit; the key input circuit is connected to the MCU controller to set test parameters ; Through RS485 communication, the test device can communicate with the host computer software of the PC to display, record and analyze the test data in real time.

Specifically, as shown in Figure 6, the relay contact measurement board includes a low-end drive constant current source circuit, a high-end drive constant current source circuit, a filter circuit, an output reverse current protection circuit, a contact test interface, The first-stage input protection circuit, the first-stage signal buffer circuit, the first-stage input signal filter circuit, the second signal buffer circuit, the second-stage input signal filter circuit, and the output-stage protection circuit, the first-stage input protection circuit is connected The contact test interface of the relay, the output end of the output stage protection circuit is a voltage feedback signal interface.

The relay contact measurement board is also provided with a contact resistance comparison circuit for indicating normal or abnormal contact resistance during the sticking test, and the comparison voltage of the contact resistance comparison circuit is taken from the first stage Input signal filter circuit output. By means of the contact resistance comparison circuit, the state of the contact can be quickly obtained when performing a stuck test.

As shown in Figure 5, the coil resistance measurement board includes a sequentially connected reference voltage source, a precision resistance network, a gear switching circuit, a low-end drive constant current source circuit, a high-end drive constant current source circuit, a filter circuit, an output Reverse current protection circuit, coil test interface, first-level input protection circuit, first-level signal buffer circuit, first-level input signal filter circuit, second signal buffer circuit, second-level input signal filter circuit, output-level protection circuit; The gear switching circuit is connected to the MCU controller through the gear switching control circuit, the first-level input protection circuit is connected to the contact test interface of the relay, and the output end of the output-level protection circuit is a voltage feedback signal interface. The reference voltage source is used to provide a fixed load current to ensure the stability of the reference voltage source; the gear switching circuit provides reference voltage values of different gears for the constant current circuit, and is switched by combining with the gear switching circuit Different constant current values; the low-end driving constant current source circuit and the high-end driving constant current source circuit are used to drive constant current output.

Preferably, the MCU controller is also connected with a temperature and humidity sensor for collecting the temperature and humidity of the test environment, an SD card for storing test data, and an indicator light for indicating the status of the safety relay test socket.

When specifically carrying out structural design, it also includes a safety relay test seat, and the safety relay test seat is provided with ten relay contact measurement boards, two coil resistance measurement boards, RS485 serial interface, and USB interface.

When in use, in the testing method of the safety relay testing device, the coil resistance measurement/stuck test switching circuit is controlled by the MCU controller to perform coil resistance measurement and stuck test switching;

When measuring the coil resistance and contact resistance, the MCU controller controls the conduction or disconnection of the electronic switch to supply power to the relay connected to the power supply circuit; the DC-DC digital control step-up module manually controls or Program-controlled output of different voltages, the coil resistance measurement board measures the coil resistance under different voltages, and uploads to the MCU controller after analog-to-digital conversion by the second ADC acquisition circuit, and the relay contact measurement board measures Contact resistances under different voltages are uploaded to the MCU controller after analog-to-digital conversion by the first ADC acquisition circuit; the MCU controller draws the action characteristics of the relay according to the coil resistance and the contact resistance Figure, through the action characteristics reflected by the contact resistance and coil resistance, the state of the relay can be tested and the automatic test of the relay can be completed.

When performing a stagnation test, input and set the coil power supply voltage, test times, test pull-in time and test interval time through the key input circuit; the DC-DC numerical control boost module program-controlled output sets the coil supply voltage, and The voltage and current acquisition circuit collects the line current value under the current voltage, and uploads it to the MCU controller after analog-to-digital conversion by the second ADC acquisition circuit. The MCU controller calculates the current coil resistance, and the relay contact measures The board measures the contact resistance under the set coil voltage, and uploads it to the MCU controller after analog-to-digital conversion by the first ADC acquisition circuit. Perform a stick-up test on the relay. Measure the resistance value of each group of contact closures, and the number of tests is adjustable; the test pull-in time can be set; the test interval time can be set; the measured resistance value for normal and abnormal tests can be set, and the number of tests that automatically stop when the test is abnormal can be set. It can program the output to set the coil power supply voltage, measure the contact resistance value of multiple groups of relay contacts at the same time, record and save the contact resistance value of each group, so as to simultaneously monitor the contact state and resistance value of the coil under different voltage conditions , Real-time measurement, to realize the automatic test of the relay.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: the present invention can still be Modifications to the specific implementation of the invention or equivalent replacement of some technical features; without departing from the spirit of the technical solution of the present invention, should be included in the scope of the technical solution claimed in the present invention.

Claims (8)

1. A safety relay testing device is characterized in that: comprise MCU controller, relay contact test module, relay coil test module, power supply protection control unit, button input circuit; The power supply includes a control unit including a power input protection control circuit, a DC-DC step-down circuit, and a DC-DC digital control boost module, and the input end of the power input protection control circuit is connected to the mains; the DC-DC digital control boost The modules are sequentially connected to the output terminal of the power input protection control circuit through the first power protection isolation circuit and the first AC-DC switching power supply to provide 12V-120V voltage; the DC-DC step-down circuit is sequentially passed through the second The power protection isolation circuit and the second AC-DC switching power supply are connected to the output end of the power input protection control circuit for providing 12V-5V voltage; The relay contact test module includes a relay contact measurement board and a first ADC acquisition circuit, the relay contact measurement board is connected to the contact of the relay to be tested in a four-wire measurement mode, and through the first ADC The acquisition circuit is connected to the MCU controller; The relay coil test module includes a coil resistance measurement/stuck test switching circuit, a coil resistance measurement board and a second ADC acquisition circuit; The coil resistance measurement/stuck test switching circuit is connected to the relay coil to be tested in a four-wire measurement mode, connected to the coil resistance measurement board, and connected to the DC-DC through the voltage and current acquisition circuit and the electronic switch in turn. CNC booster module; The electronic switch is connected to the MCU controller through an IO isolation drive circuit; The MCU controller is connected to the voltage and current acquisition circuit and the coil resistance measurement board through the second ADC acquisition circuit, and is connected to the coil resistance measurement/stuck test switching circuit through the switch state feedback circuit ; The key input circuit is connected to the MCU controller for setting test parameters. 2. The safety relay testing device according to claim 1, characterized in that: it also includes a safety relay test seat, and the safety relay test seat is provided with ten relay contact measurement boards, two coil resistance measurement boards, RS485 Serial interface, USB interface. 3. safety relay testing device according to claim 2, is characterized in that: described MCU controller is also connected with the temperature and humidity sensor that is used to collect test environment temperature and humidity, is used for the SD card of storing test data, and is used for safety. Indicator light for relay test socket status indication. 4. The safety relay testing device according to claim 3, characterized in that: The relay contact measurement board includes a low-end driving constant current source circuit, a high-end driving constant current source circuit, a filter circuit, an output reverse current protection circuit, a contact test interface, a first-level input protection circuit, and a first-level input protection circuit connected in sequence. Level signal buffer circuit, first level input signal filter circuit, second signal buffer circuit, second level input signal filter circuit, output level protection circuit, the first level input protection circuit is connected to the contact test interface of the relay, and the The output end of the output stage protection circuit is a voltage feedback signal interface. 5. The safety relay testing device according to claim 4, characterized in that: said relay contact measurement board is also provided with a contact resistance comparison circuit for normal or abnormal indication of contact resistance during the sticking test, The comparison voltage of the contact resistance comparison circuit is obtained from the output of the first stage input signal filter circuit. 6. The safety relay testing device according to claim 3, characterized in that: the coil resistance measuring board includes a reference voltage source, a precision resistor network, a gear switching circuit, and a low-end driving constant current source circuit connected in sequence , high-end drive constant current source circuit, filter circuit, output reverse current protection circuit, coil test interface, first-level input protection circuit, first-level signal buffer circuit, first-level input signal filter circuit, second signal buffer circuit, second Level input signal filter circuit, output level protection circuit; the gear switching circuit is connected to the MCU controller through the gear switching control circuit, the first level input protection circuit is connected to the contact test interface of the relay, and the output level The output end of the protection circuit is a voltage feedback signal interface. 7. a method of testing of the safety relay testing device according to claim 1, characterized in that: Controlling the coil resistance measurement/stuck test switching circuit by the MCU controller to switch between coil resistance measurement and stuck test; When measuring the coil resistance and contact resistance, the MCU controller controls the conduction or disconnection of the electronic switch to supply power to the relay connected to the power supply circuit; the DC-DC digital control step-up module manually controls or Program-controlled output of different voltages, the coil resistance measurement board measures the coil resistance under different voltages, and uploads to the MCU controller after analog-to-digital conversion by the second ADC acquisition circuit, and the relay contact measurement board measures Contact resistances under different voltages are uploaded to the MCU controller after analog-to-digital conversion by the first ADC acquisition circuit; the MCU controller draws the action characteristics of the relay according to the coil resistance and the contact resistance picture; When performing a stagnation test, input and set the coil power supply voltage, test times, test pull-in time and test interval time through the key input circuit; the DC-DC numerical control boost module program-controlled output sets the coil supply voltage, and The voltage and current acquisition circuit collects the line current value under the current voltage, and uploads it to the MCU controller after analog-to-digital conversion by the second ADC acquisition circuit. The MCU controller calculates the current coil resistance, and the relay contact measures The board measures the contact resistance under the set coil voltage, and uploads it to the MCU controller after analog-to-digital conversion by the first ADC acquisition circuit. 8. The testing method of the safety relay testing device according to claim 1, characterized in that: the relay contact measuring board is also provided with a contact resistance value comparison for normal or abnormal indication of contact resistance during the sticking test Circuit, the comparison voltage of the contact resistance comparison circuit is taken from the output of the first-stage input signal filter circuit; when performing a stuck test, the preset test is normal and the test is abnormal. The measured resistance value and the test that the test is abnormal automatically stop The number of times, when the number of tests that automatically stop when the test is abnormal reaches, it means that the relay is stuck and the test is automatically stopped.