Handheld Relay Tester

Abstract

The present invention discloses a handheld relay tester, comprising a control module, a driving module and a contact detection module; the driving module is used to connect with the coil of the relay to be tested, and the contact detection module is used to connect with the contact of the relay to be tested; the control module is used to output a PWM wave to the driving module, and the driving module drives the coil of the relay to be tested according to the PWM wave to make the relay to be tested actuate; the contact detection module is used to generate an action electrical signal according to the action of the relay to be tested, and output the action electrical signal to the control module, and the control module is also used to output a test result according to the action electrical signal and the PWM wave. The driving module drives the relay to be tested by using the PWM wave, and the action electrical signal generated by the contact detection module according to the action of the relay to be tested is obtained at the same time, and the test result is obtained by comparing the action electrical signal and the PWM wave; the bad relays such as aging can be detected conveniently, quickly and accurately.

Description

Technical Field

[0001] The invention relates to detection technology, in particular to a handheld relay tester. Background Art

[0002] Relays are a common component, but they are usually required to have high reliability. For example, a large number of relays are used inside the special test equipment used to detect the performance of semiconductor products. The relays used in the test equipment are required to have a fast response speed and a contact resistance of less than 0.2Ω. Relay aging may cause problems such as increased contact resistance or delayed response speed. Therefore, relay aging is the main factor causing the instability of test equipment. Therefore, how to conveniently, quickly and accurately detect aging and other defective relays is a technical problem that needs to be solved. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the present invention aims to provide a handheld relay tester that can conveniently, quickly and accurately detect defective relays such as aging.

[0004] The purpose of the present invention is achieved by the following technical solutions:

[0005] A handheld relay tester comprises a control module, a drive module and a contact detection module; the drive module is used to connect with the coil of the relay to be tested, and the contact detection module is used to connect with the contact of the relay to be tested;

[0006] The control module is used to output a PWM wave to the driving module, and the driving module drives the coil of the relay under test according to the PWM wave to make the relay under test operate; the contact detection module is used to generate an action electrical signal according to the action of the relay under test, and output the action electrical signal to the control module, and the control module is also used to output a test result according to the action electrical signal and the PWM wave.

[0007] In some implementations, the coil of the relay to be tested includes a first end and a second end, the driving module includes a bridge commutation unit, and the bridge commutation unit is used to supply power to the coil; the control module controls the bridge commutation unit to output a current from the first end to the second end to the coil, or controls the bridge commutation unit to output a current from the second end to the first end to the coil.

[0008] In some implementations, the driving module further includes a current detection unit for detecting a current flowing through the coil;

[0009] The control module is used to obtain the current flowing through the coil from the current detection unit, and when the current flowing through the coil is greater than a preset value, control the bridge commutation unit to switch the direction of outputting the current to the coil.

[0010] In some implementations, the current detection unit includes a sampling element and an amplifying circuit, the sampling element is connected in series to a loop through which the bridge commutation unit supplies power to the coil, the amplifying circuit amplifies the output of the sampling element and transmits it to the control module, and the control module is used to calculate the current flowing through the coil based on the output of the amplifying circuit.

[0011] In some implementations, the driving module further includes a driving power supply unit, and the driving power supply unit supplies power to the coil through the bridge commutation unit.

[0012] In some implementations, one end of the bridge commutation unit is connected to the driving power supply unit, and the other end is connected to the ground terminal of the power supply through the current detection unit.

[0013] In some implementations, the control module is also used to control the drive power supply unit to increase the voltage output to the bridge commutation unit when the current flowing through the coil is not greater than a preset value and no action electrical signal generated according to the action of the relay to be tested is received from the contact detection module.

[0014] In some implementations, the driving power supply unit includes a first voltage unit and a second voltage unit connected to the control module, and the voltage output by the first voltage unit is smaller than the voltage output by the second voltage unit;

[0015] The control module controls the first voltage unit to supply power to the coil through the bridge commutation unit. If the control module determines that the current flowing through the coil is not greater than a preset value and does not receive an action electrical signal generated according to the action of the relay to be tested from the contact detection module, the control module controls the second voltage unit to supply power to the coil through the bridge commutation unit.

[0016] In some implementations, the first voltage unit includes a first power branch and a switch tube Q5 and a power member K2-A connected in series, the first power branch includes an action switch K6-B coupled to the power member K2-A; when the control module controls the switch tube Q5 to turn on, the power member K2-A closes the action switch K6-B, so that the first voltage unit outputs voltage to the bridge commutation unit;

[0017] The second voltage unit includes a second power supply branch and a switch tube Q6 and a power component K3-A connected in series, and the second power supply branch includes an action switch K7-B coupled to the power component K3-A; when the control module controls the switch tube Q6 to turn on, the power component K3-A closes the action switch K7-B so that the second voltage unit outputs voltage to the bridge commutation unit.

[0018] In some embodiments, the bridge commutation unit includes a first switch half-bridge and a second switch half-bridge connected in parallel, the first switch half-bridge includes a switch tube Q10 and a switch tube Q11 connected in series, the second switch half-bridge includes a switch tube Q9 and a switch tube Q12 connected in series, the first end of the coil is connected to the connection between the switch tube Q10 and the switch tube Q11, the second end of the coil is connected to the connection between the switch tube Q9 and the switch tube Q12, and the switch tube Q10, the switch tube Q11, the switch tube Q9 and the switch tube Q12 are all controlled by the control module to be turned on or off.

[0019] In some implementations, the switch tube Q10 and the switch tube Q11 are connected to the first driving end of the control module, and the switch tube Q9 and the switch tube Q12 are connected to the second driving end of the control module;

[0020] The switch tubes Q10 and Q9 are PMOS tubes, and the switch tubes Q11 and Q12 are NMOS tubes; or

[0021] The switch tubes Q10 and Q9 are NMOS tubes, and the switch tubes Q11 and Q12 are PMOS tubes.

[0022] In some embodiments, the relay to be tested includes a first group of contacts, and the contact detection module includes a first contact detection unit; the first contact detection unit is used to compare the resistance when the first group of contacts is connected with a preset resistance value, and if the first group of contacts is connected and the resistance when connected is less than the preset resistance value, output an interrupt signal to the control module.

[0023] In some implementations, the first contact point detection unit includes a resistance bridge unit and a first comparison unit, one end of the resistance bridge unit is connected to a positive terminal of a power supply, and the other end is connected to a ground terminal of the power supply; the resistance bridge unit includes a first resistance half-bridge and a second resistance half-bridge connected in parallel, the first resistance half-bridge includes a resistor R3 and a resistor R5 connected in series, and the second resistance half-bridge includes a resistor R4 and a resistor R6 connected in series; the first group of contacts is connected to the resistor R3, the resistor R5, the resistor R4 or the resistor R6;

[0024] The first input end of the first comparison unit is connected between the resistor R3 and the resistor R5 , the second input end of the first comparison unit is connected to the connection between the resistor R4 and the resistor R6 , and the output end IN1 of the first comparison unit is connected to the control module.

[0025] In some implementations, the resistance bridge unit further includes an adjusting resistor R2 for adjusting a preset resistance value, the first group of contacts is connected in series with the resistor R3, and the adjusting resistor R2 is connected in parallel with the resistor R5.

[0026] In some implementations, the relay to be tested also includes a second group of contacts, and the contact detection module also includes a second contact detection unit; the second contact detection unit is used to compare the resistance when the second group of contacts is connected with a preset resistance value, and if the second group of contacts is connected and the resistance when connected is less than the preset resistance value, output an interrupt signal to the control module.

[0027] In some embodiments, the second contact detection unit includes a resistor R10, a resistor R9, a resistor R11, and a second comparison unit; one end of the second group of contacts is connected to the resistor R3, and the other end is connected to the ground terminal of the power supply through the resistor R10, and is connected to the third input terminal of the second comparison unit, one end of the resistor R9 is connected to the positive terminal of the power supply, and the other end is connected to the ground terminal of the power supply through the resistor R11, and is connected to the fourth input terminal of the second comparison unit, and the output terminal IN2 of the second comparison unit is connected to the control module.

[0028] In some implementations, the second contact detection unit further includes an adjusting resistor R8 for adjusting a preset resistance, and the adjusting resistor R8 is connected in parallel with the resistor R10 or the resistor R9.

[0029] In some embodiments, the handheld relay tester also includes a display screen and buttons connected to the control module, the display screen is used to display the test results, as well as the frequency, duty cycle and current test number of the PWM wave, and the button is used to set the frequency, duty cycle and total test number of the PWM wave output by the control module to the drive module.

[0030] In some implementations, the handheld relay tester further includes a prompt unit connected to the control module, and the prompt unit is used to indicate the operating state of the relay to be tested.

[0031] Compared with the prior art, the beneficial effects of the embodiments of the present invention are: using PWM waves to enable the driving module to drive the relay to be tested, and at the same time obtaining the action electrical signal generated by the contact detection module according to the action of the relay to be tested, and obtaining the test result by comparing the action electrical signal and the PWM wave; defective relays such as aging can be detected conveniently, quickly and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of a handheld relay tester provided in an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of an action electrical signal and a PWM wave generated according to the action of the relay to be tested;

[0034] Figure 3 for Figure 1 Circuit diagram of the control module;

[0035] Figure 4 for Figure 1 Circuit diagram of the middle drive module;

[0036] Figure 5 for Figure 4 A circuit diagram of a control part of the first voltage unit, the second voltage unit and the third voltage unit;

[0037] Figure 6 for Figure 1 Circuit diagram of the middle contact detection module;

[0038] Figure 7 A schematic diagram of a circuit for a key connected to a control module;

[0039] Figure 8 It is a circuit diagram of a prompt unit connected to a control module.

[0040] In the figure: 110, control module; 120, drive module; 121, drive power supply unit; 1211, first voltage unit; 1212, second voltage unit; 122, bridge commutation unit; 123, current detection unit; 1231, sampling element; 1232, amplifier circuit; 130, contact detection module; 131, first contact detection unit; 1311, resistance bridge unit; 1312, first comparison unit; 132, second contact detection unit; 1321, second comparison unit; 140, interface module; 141, coil end interface; 142, contact end interface; 200, relay to be tested; 210, coil; 211, first end; 212, second end; 220, contact. DETAILED DESCRIPTION

[0041] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0042] like Figure 1 Shown is a schematic diagram of the structure of a handheld relay tester.

[0043] The handheld relay tester comprises a control module 110, a drive module 120 and a contact detection module 130. The drive module 120 is used to connect with the coil 210 of the relay 200 to be tested, and the contact detection module 130 is used to connect with the contact 220 of the relay 200 to be tested.

[0044] In some feasible embodiments, the handheld relay tester also includes an interface module 140, the interface module 140 includes a coil end interface 141 for connecting to the coil 210 of the relay 200 to be tested, and a contact end interface 142 for connecting to the contact 220 of the relay 200 to be tested; the drive module 120 is connected between the control module 110 and the coil end interface 141, and the contact detection module 130 is connected between the control module 110 and the contact end interface 142.

[0045] The control module 110 is used to output a PWM (Pulse Width Modulation) wave, ie, a pulse width modulation wave, to the driving module 120. Exemplarily, the frequency of the PWM wave output by the control module 110 to the driving module 120 is 0 Hz-30 Hz, and the duty cycle is 10%-90%.

[0046] The driving module 120 drives the coil 210 of the relay 200 to be tested according to the PWM wave to make the relay 200 to be tested actuate; illustratively, the relay 200 to be tested connects the common contact with the normally open contact at the rising edge of the PWM wave, and disconnects the common contact with the normally open contact at the falling edge of the PWM wave. The contact detection module 130 is used to generate an action electrical signal according to the action of the relay 200 to be tested, and output the action electrical signal to the control module 110, and the control module 110 is also used to output the test result according to the received action electrical signal and the PWM wave.

[0047] like Figure 2 As shown, the first waveform represents the voltage waveform applied by the driving module 120 to the coil 210 of the relay 200 under test. The second waveform and the third waveform represent the action electrical signal waveforms generated by the contact detection module 130 according to the action of the relay 200 under test. The rising edge of the second waveform and the third waveform represents that the common contact of the relay 200 under test is connected to the normally open contact, and the falling edge represents that the common contact of the relay 200 under test is disconnected from the normally open contact.

[0048] Comparing the second waveform with the first waveform, it can be concluded that the action state of the relay 200 under test, that is, the connection and disconnection of the common contact and the normally open contact, are synchronized with the rising edge and the falling edge of the voltage waveform applied to the coil 210 of the relay 200 under test, so the relay 200 under test can correctly operate according to the waveform of the drive coil 210 and switch the switch state. However, when the second waveform is compared with the first waveform, the action state of the relay 200 under test and the rising edge and the falling edge of the voltage waveform applied to the coil 210 of the relay 200 under test are sometimes not synchronized. At M1, the action of the relay 200 under test is delayed compared to the waveform applied to the coil 210, so the relay 200 under test has a response lag phenomenon; at M2, the relay 200 under test does not respond to the drive module 120 on the coil 210; at M3, when the voltage waveform applied to the coil 210 of the relay 200 under test is not yet at the falling edge, the common contact of the relay 200 under test is disconnected from the normally open contact in advance, indicating that the connection between the common contact of the relay 200 under test and the normally open contact cannot be maintained for a sufficient time, and there is a phenomenon of premature disconnection.

[0049] In some feasible embodiments, the PWM wave output by the control module 110 to the driving module 120 includes a number of cycles, such as 1-2000 cycles, so that the on-off detection of the relay 200 to be tested can be performed the same number of times as the number of cycles contained in the PWM wave. Figure 2 As shown, the voltage waveform represented by the first waveform applied by the driving module 120 to the coil 210 of the relay 200 under test includes 5 cycles, so the relay 200 under test can be tested 5 times. The second waveform indicates that the relay 200 under test can operate correctly in all 5 tests; the third waveform indicates that the relay 200 under test can only operate correctly twice in 5 tests, so the relay 200 under test corresponding to the third waveform is a bad relay.

[0050] In some feasible embodiments, when the number of times the action of the relay 200 to be tested is not synchronized with the PWM wave reaches a preset threshold, the relay 200 to be tested is judged to be a bad relay and the detection can be terminated in advance; in other feasible embodiments, the PWM wave output by the control module 110 to the drive module 120 includes several cycles. When the ratio of the number of times the action of the relay 200 to be tested is synchronized with the PWM wave to the number of cycles is not greater than a proportional threshold, or when the ratio of the number of times the action of the relay 200 to be tested is not synchronized with the PWM wave to the number of cycles is greater than the proportional threshold, the relay 200 to be tested is judged to be a bad relay.

[0051] like Figure 3 As shown, the control module 110 includes a processor chip U3. Exemplarily, the processor chip U3 adopts an STC single-chip microcomputer, for example, a chip with a model number of STC12C5A6052.

[0052] In some possible embodiments, such as Figure 3 As shown, the handheld relay tester also includes a display screen J1 connected to the control module 110. The control module 110 uses the display screen J1 for user information interaction, displays test parameters and test data, and can output test results, such as outputting information indicating that the relay 200 to be tested is qualified and / or unqualified, the number of times the action of the relay 200 to be tested is synchronized and / or asynchronous with the PWM wave, or the number of cycles included in the PWM wave, that is, the total number of times required to be tested.

[0053] Exemplarily, the display screen J1 may use LCD1206, LCD12864 or OLED screen.

[0054] In some possible embodiments, such as Figure 4 As shown, the coil 210 of the relay 200 to be tested includes a first end 211 and a second end 212 , and the driving module 120 includes a bridge commutation unit 122 , and the bridge commutation unit 122 is used to supply power to the coil 210 .

[0055] The control module 110 controls the bridge commutation unit 122 to output a current from the first end 211 to the second end 212 to the coil 210, or controls the bridge commutation unit 122 to output a current from the second end 212 to the first end 211 to the coil 210. Thus, the control module 110 can switch the direction of the current applied to the coil 210 of the relay 200 to be tested through the bridge commutation unit 122. When testing a batch of relays 200 to be tested of a certain model, the control module 110 controls the bridge commutation unit 122 to output a current in one direction to the coil 210, and when testing another batch of relays 200 to be tested of another model, the control module 110 controls the bridge commutation unit 122 to output a current in another direction to the coil 210; thereby expanding the test object range of the handheld relay tester.

[0056] In some feasible embodiments, the bridge commutation unit 122 includes a first switch half-bridge and a second switch half-bridge connected in parallel; wherein the first switch half-bridge includes a switch tube Q10 and a switch tube Q11 connected in series, and the second switch half-bridge includes a switch tube Q9 and a switch tube Q12 connected in series. The first end 211 of the coil 210 is connected to the connection between the switch tube Q10 and the switch tube Q11, and the second end 212 of the coil 210 is connected to the connection between the switch tube Q9 and the switch tube Q12. The switch tubes Q10, Q11, Q9, and Q12 are all controlled to be turned on or off by the control module 110.

[0057] In some feasible embodiments, the switch tubes Q10 and Q11 are connected to the first driving end DRIVER_H of the control module 110, and the switch tubes Q9 and Q12 are connected to the second driving end DRIVER_L of the control module 110. The switch tubes Q10 and Q9 are PMOS tubes, and the switch tubes Q11 and Q12 are NMOS tubes; or the switch tubes Q10 and Q9 are NMOS tubes, and the switch tubes Q11 and Q12 are PMOS tubes.

[0058] In some feasible embodiments, the driving module 120 further includes a current detection unit 123 for detecting the current flowing through the coil 210 of the relay 200 to be tested.

[0059] The control module 110 is used to obtain the current flowing through the coil 210 from the current detection unit 123. When the control module 110 detects that the current flowing through the coil 210 is greater than a preset value, it can be determined that the positive and negative poles of the coil 210 are connected in reverse, that is, the bridge commutation unit 122 outputs a current in the opposite direction to the coil 210. Thus, the control module 110 can control the bridge commutation unit 122 to switch the direction of the current output to the coil 210. Therefore, when the direction of the current applied to the coil 210 of the relay 200 to be tested does not match the requirements of the relay 200 to be tested, the direction of the current output to the coil 210 can be automatically realized more positively according to the current flowing through the coil 210 obtained from the current detection unit 123. Therefore, even when a batch of relays 200 to be tested with different models are tested, it is not necessary to carefully distinguish the positive and negative poles of the coil 210 of the relay 200 to be tested.

[0060] In some feasible embodiments, the current detection unit 123 includes a sampling element 1231 and an amplifying circuit 1232 . The sampling element 1231 is connected in series to a loop through which the bridge commutation unit 122 supplies power to the coil 210 .

[0061] In this embodiment, the amplifier circuit 1232 includes a chip U6-A of model LM358 and a resistor network connected to the chip U6-A; the chip U6-A and the resistor network constitute a reverse proportional operational amplifier circuit 1232.

[0062] The amplifier circuit 1232 amplifies the output of the sampling element 1231 and transmits the amplified output to the control module 110 . The control module 110 is used to calculate the current flowing through the coil 210 according to the output of the amplifier circuit 1232 .

[0063] Exemplarily, the sampling element 1231 includes a sampling resistor R27, which can convert the current flowing through the coil 210 into a voltage value, and the voltage value is transmitted to the control module 110 after being processed by the amplifier circuit 1232. The processor chip U3 in the control module 110 can have an analog-to-digital conversion function, which can convert the signal processed by the amplifier circuit 1232 into a digital value; or the control module 110 also includes an analog-to-digital conversion device connected to the processor chip U3, and the voltage value is converted into a digital value by the analog-to-digital conversion device after being processed by the amplifier circuit 1232 and transmitted to the control module 110. Therefore, the control module 110 can be used to calculate the current flowing through the coil 210 according to the output of the amplifier circuit 1232.

[0064] In some feasible embodiments, the driving module 120 further includes a driving power supply unit 121 , and the driving power supply unit 121 supplies power to the coil 210 through a bridge commutation unit 122 .

[0065] In some feasible embodiments, one end of the bridge commutation unit 122 is connected to the drive power supply unit 121, and the other end is connected to a low level, such as grounding, through the sampling element 1231 in the current detection unit 123; this facilitates the reasonable arrangement of the bridge commutation unit 122, the sampling element 1231, and the amplification circuit 1232 on the circuit board.

[0066] In some feasible embodiments, the control module 110 is also used to control the driving power supply unit 121 to increase the voltage output to the bridge commutation unit 122 when the current flowing through the coil 210 of the relay 200 to be tested is not greater than the preset value and the action electrical signal generated according to the action of the relay 200 to be tested is not received from the contact detection module 130. The current flowing through the coil 210 of the relay 200 to be tested is not greater than the preset value, indicating that the current applied to the coil 210 is not reversed, but the relay 200 to be tested does not act at this time, which may be because the voltage provided by the bridge commutation unit 122 to the coil 210 is too small; for example, the voltage of the coil 210 required by the relay 200 to be tested is 12V, but the voltage provided by the bridge commutation unit 122 to the coil 210 is 5V, then the driving power supply unit 121 needs to increase the voltage output to the bridge commutation unit 122 to meet the voltage of the coil 210 required by the relay 200 to be tested.

[0067] In some possible embodiments, such as Figure 4As shown, the driving power supply unit 121 includes a first voltage unit 1211 and a second voltage unit 1212 connected to the control module 110, and the voltage output by the first voltage unit 1211 is less than the voltage output by the second voltage unit 1212. In this embodiment, the voltage output by the first voltage unit 1211 to the bridge commutation unit 122 is 5V, and the voltage output by the second voltage unit 1212 to the bridge commutation unit 122 is 12V; in another implementation, the voltage output by the first voltage unit 1211 to the bridge commutation unit 122 is 12V, and the voltage output by the second voltage unit 1212 to the bridge commutation unit 122 is 24V.

[0068] If the control module 110 determines that the current flowing through the coil 210 is not greater than the preset value, and does not receive the action electrical signal generated according to the action of the relay 200 to be tested from the contact detection module 130, the control module 110 controls the first voltage unit 1211 to supply power to the coil 210 through the bridge commutation unit 122, and switches to controlling the second voltage unit 1212 to supply power to the coil 210 through the bridge commutation unit 122; thereby achieving the voltage provided by the bridge commutation unit 122 to the coil 210 to increase from 5V to 12V, or from 12V to 24V.

[0069] In this embodiment, the driving power supply unit 121 includes a first voltage unit 1211, a second voltage unit 1212, and a third voltage unit; the voltage output by the first voltage unit 1211 is less than the voltage output by the second voltage unit 1212, and the voltage output by the second voltage unit 1212 is less than the voltage output by the third voltage unit. The voltage output by the first voltage unit 1211 to the bridge commutation unit 122 is 5V, the voltage output by the second voltage unit 1212 to the bridge commutation unit 122 is 12V, and the voltage output by the third voltage unit to the bridge commutation unit 122 is 24V.

[0070] In some possible embodiments, such as Figure 4 and Figure 5 As shown, the first voltage unit 1211 includes a first power branch and a switch tube Q5 and a power piece K2-A connected in series, and the first power branch includes an action switch K6-B coupled to the power piece K2-A. When the control module 110 controls the switch tube Q5 to turn on, the power piece K2-A closes the action switch K6-B, so that the first voltage unit 1211 outputs a voltage to the bridge commutation unit 122.

[0071] The second voltage unit 1212 includes a second power branch and a switch tube Q6 and a power component K3-A connected in series. The second power branch includes an action switch K7-B coupled to the power component K3-A.

[0072] The third voltage unit includes a third power supply branch and a switch tube Q7 and a power component K4-A connected in series. The second power supply branch includes an action switch K8-B coupled to the power component K4-A.

[0073] When the control module 110 controls the switch tube Q6 to be turned on, the power component K3 -A closes the action switch K7 -B, so that the second voltage unit 1212 outputs voltage to the bridge commutation unit 122 .

[0074] If the control module 110 determines that the current flowing through the coil 210 is not greater than the preset value, and does not receive the action electrical signal generated according to the action of the relay 200 to be tested from the contact detection module 130, the control module 110 controls the switch tube Q5 to turn off, the power part K2-A loses power, so that the action switch K6-B is disconnected, and the first voltage unit 1211 stops outputting voltage to the bridge commutation unit 122; and the control module 110 controls the switch tube Q6 to turn on, the power part K3-A is powered on, so that the action switch K7-B is closed, and the second voltage unit 1212 starts to output voltage to the bridge commutation unit 122. In this embodiment, the first power branch is connected to a 5V level, and the second power branch is connected to a 12V level. Thereby, the voltage provided by the bridge commutation unit 122 to the coil 210 is increased from 5V to 12V; in another embodiment, the second power supply branch is connected to the 12V level, and the second power supply branch is connected to the 24V level; thereby, the voltage provided by the bridge commutation unit 122 to the coil 210 is increased from 12V to 24V.

[0075] In some feasible embodiments, the control module 110 first controls the driving power supply unit 121 to apply a relatively low voltage, such as 5V, to the coil 210 of the relay 200 to be tested through the bridge commutation unit 122, and the direction of the voltage on the coil 210 is, for example, from the first end 211 to the second end 212; if the control module 110 detects that the current flowing through the coil 210 is greater than a preset value, that is, the positive and negative poles of the coil 210 are connected in reverse, the bridge commutation unit 122 is controlled to switch the direction of the current output to the coil 210, and the relatively low voltage is applied to the coil 210 of the relay 200 to be tested, and the direction of the voltage on the coil 210 is, for example, from the second end 212 to the first end 211. If the control module 110 still does not receive the action electrical signal generated according to the action of the relay 200 to be tested from the contact detection module 130 at this time, the control module 110 controls the driving power supply unit 121 to apply a relatively high voltage, such as 12V, to the coil 210 of the relay 200 to be tested through the bridge commutation unit 122.

[0076] In some feasible embodiments, after a voltage of 12V is applied to the coil 210, if the control module 110 still has not received an action electrical signal generated according to the action of the relay 200 to be tested from the contact detection module 130, the control module 110 controls the driving power supply unit 121 to apply a higher voltage, such as 24V, to the coil 210 of the relay 200 to be tested through the bridge switching unit 122.

[0077] By means of the driving power supply unit 121 capable of outputting various voltage values ​​to the bridge switching unit 122, the voltage applied to the coil 210 of the relay 200 to be tested can be automatically adjusted, thereby realizing the detection of relays 200 to be tested with various voltage specifications, thereby further expanding the test object range of the handheld relay tester. Moreover, by applying voltages from small to large to the coil 210 of the relay 200 to be tested, the relay 200 itself can be prevented from being damaged, and the peripheral circuits of the relay 200 to be tested on the circuit board can be prevented from being damaged, thereby realizing the online test of the relay.

[0078] In some possible embodiments, such as Figure 6 As shown, the relay 200 to be tested includes a first set of contacts, and the contact terminal interface 142 is used to connect the first set of contacts of the relay 200 to be tested. Exemplarily, the first set of contacts includes a common contact COM and a normally closed contact NC.

[0079] The contact detection module 130 includes a first contact detection unit 131, which is used to compare the resistance when the first group of contacts are connected with a preset resistance value, and if the first group of contacts are connected and the resistance when connected is less than the preset resistance value, an interrupt signal is output to the control module 110 to generate an action electrical signal according to the action of the relay 200 to be tested.

[0080] In some feasible embodiments, the contact detection module 130 is connected to the external interrupt input port of the processor chip U3 in the control module 110; therefore, the control module 110 can detect the action response of the relay 200 to be tested in real time by receiving the interrupt.

[0081] When the voltage waveform applied to the coil 210 of the relay 200 under test is at the rising edge, the relay 200 under test is actuated, and the common contact COM is disconnected from the normally closed contact NC; when the voltage waveform applied to the coil 210 of the relay 200 under test is at the falling edge, the relay 200 under test is actuated again, and the first group of contacts is connected, that is, the common contact COM is connected to the normally closed contact NC.

[0082] When the first group of contacts is connected, if the resistance of the first group of contacts when connected is greater than a preset resistance, such as 0.2 ohms, the connection between the current common contact COM and the normally closed contact NC is unreliable, and the contact detection module 130 does not output an interrupt signal to the control module 110, that is, does not output an action electrical signal; the control module 110 can determine that the relay 200 under test did not operate correctly in this test based on the absence of the action electrical signal waveform.

[0083] In some possible embodiments, such as Figure 6 As shown, the first contact point detection unit 131 includes a resistance bridge unit 1311 and a first comparison unit 1312. Exemplarily, the first comparison unit 1312 includes a comparator U1.

[0084] One end of the resistance bridge unit 1311 is connected to the positive terminal of a power supply, whose voltage is, for example, 24V, and the other end is connected to the ground terminal of the power supply. The resistance bridge unit 1311 includes a first resistance half-bridge and a second resistance half-bridge connected in parallel, the first resistance half-bridge includes a resistor R3 and a resistor R5 connected in series, and the second resistance half-bridge includes a resistor R4 and a resistor R6 connected in series.

[0085] The first group of contacts is connected to the resistor R3, the resistor R5, the resistor R4 or the resistor R6; for example, connected in series or in parallel with one of the resistors R3, R5, R4 and R6. In this embodiment, the first group of contacts, i.e., the common contact COM and the normally closed contact NC are connected in series in the branch of the resistor R3.

[0086] The first input terminal of the first comparison unit 1312 is connected between the branch where the resistor R3 is located and the resistor R5 , and the second input terminal of the first comparison unit 1312 is connected to the connection between the resistor R4 and the resistor R6 . The output terminal IN1 of the first comparison unit 1312 is connected to the control module 110 .

[0087] If the resistance when the first set of contacts is connected is greater than the preset resistance, such as greater than 0.2 ohms, the first comparison unit 1312 outputs an interrupt signal to the control module 110 through the output terminal IN1 according to the voltage difference between the first input terminal and the second input terminal. The comparison between the resistance when the first set of contacts is connected and the preset resistance is realized by the resistance bridge unit 1311, with a higher accuracy, which can reach 0.05 ohms. In some feasible embodiments, the resistors R3, R5, R4, and R6 use high-precision resistors with an error of 0.1%.

[0088] In some feasible embodiments, the resistance bridge unit 1311 further includes an adjusting resistor R2 for adjusting the preset resistance value, the first group of contacts is connected in series with the resistor R3, and the adjusting resistor R2 is connected in parallel with the resistor R5. Thus, the preset resistance value can be adjusted, and the preset resistance value can be adjusted by adjusting the resistor R2 according to the model and batch of the relay 200 to be tested, so as to achieve the accuracy of the test.

[0089] In some feasible embodiments, the relay 200 under test further includes a second set of contacts, and the contact terminal interface 142 is further used to connect the second set of contacts of the relay 200 under test. Exemplarily, the second set of contacts includes a common contact COM and a normally open contact NO.

[0090] The contact detection module 130 also includes a second contact detection unit 132, which is used to compare the resistance when the second group of contacts are connected with a preset resistance value, and if the second group of contacts are connected and the resistance when connected is less than the preset resistance value, an interrupt signal is output to the control module 110 as an action electrical signal generated according to the action of the relay 200 to be tested.

[0091] When the voltage waveform applied to the coil 210 of the relay 200 under test is at the rising edge, the relay 200 under test is actuated, and the common contact COM is connected to the normally open contact NO; when the voltage waveform applied to the coil 210 of the relay 200 under test is at the falling edge, the relay 200 under test is actuated again, and the second group of contacts is disconnected, that is, the common contact COM is disconnected from the normally open contact NO.

[0092] When the second group of contacts is connected, if the resistance when the second group of contacts is connected is greater than the preset resistance, such as greater than 0.2 ohms, the connection between the current common contact COM and the normally open contact NO is unreliable, and the contact detection module 130 does not output an interrupt signal to the control module 110, that is, does not output an action electrical signal; the control module 110 can determine that the relay 200 under test did not operate correctly in this test based on the absence of the action electrical signal waveform.

[0093] In some feasible embodiments, the second contact detection unit 132 includes a resistor R10, a resistor R9, a resistor R11, and a second comparison unit 1321; illustratively, the second comparison unit 1321 includes a comparator U5.

[0094] One end of the second group of contacts is connected to the resistor R3 , and the other end is connected to the ground of the power supply through the resistor R10 , and is connected to the third input end of the second comparison unit 1321 .

[0095] One end of the resistor R9 is connected to the positive end of the power supply, and its voltage is, for example, 24V. The other end is connected to the ground end of the power supply through the resistor R11, and is connected to the fourth input end of the second comparison unit 1321. The output end IN2 of the second comparison unit 1321 is connected to the control module 110.

[0096] Therefore, the resistors R10, R9, R11 and R3 form another resistor bridge, which enables comparison of the resistance when the second group of contacts are connected with the preset resistance value with higher accuracy.

[0097] In some feasible embodiments, the second contact detection unit 132 further includes an adjusting resistor R8 for adjusting the preset resistance, and the adjusting resistor R8 is connected in parallel with the resistor R10. Thus, the preset resistance can be adjusted, and the preset resistance can be adjusted by adjusting the resistor R8 according to the model and batch of the relay 200 to be tested, so as to achieve the accuracy of the test.

[0098] like Figure 7 As shown, the handheld relay tester also includes a button connected to the control module 110. For example, in this embodiment, buttons S1-A, S2-A, S3-A, and S4-A are connected to the control module 110. The display screen J1 is used to display the test results, as well as the frequency, duty cycle, and current test times of the PWM wave. The buttons are used to set the frequency, duty cycle, and total test times of the PWM wave output by the control module 110 to the drive module 120. Exemplarily, the buttons S1-A, S2-A, S3-A, and S4-A are respectively a menu button, an up jump button, a down jump button, and a confirmation button, wherein the confirmation button has the multiplexing functions of starting the test, pausing, and stopping the test.

[0099] In some possible embodiments, such as Figure 8 As shown, the handheld relay tester also includes a prompt unit connected to the control module 110. The prompt unit is used to indicate the operating state of the relay 200 to be tested. Exemplarily, the prompt unit includes a buzzer U4 and an indicator light D1 and an indicator light D2. Exemplarily, when the contact detection module 130 outputs an interrupt signal to the control module 110, the control module 110 drives the indicator lights D1 and D2 to indicate the working state of the relay, and drives the buzzer to prompt the test result.

[0100] The handheld relay tester provided in the embodiment of the present invention uses PWM waves to enable the driving module 120 to drive the relay 200 to be tested, and at the same time obtains the action electrical signal generated by the contact detection module 130 according to the action of the relay 200 to be tested, and obtains the test result by comparing the action electrical signal and the PWM wave; it can conveniently, quickly and accurately detect defective relays such as aging.

[0101] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. Handheld relay tester, characterized by: It includes a control module, a driving module and a contact detection module; the driving module is used to connect with the coil of the relay to be tested, and the contact detection module is used to connect with the contact of the relay to be tested; The control module is used to output a PWM wave to the driving module, and the driving module drives the coil of the relay to be tested according to the PWM wave to make the relay to be tested actuate; the contact detection module is used to generate an action electrical signal according to the action of the relay to be tested, and output the action electrical signal to the control module, and the control module is also used to output a test result according to the action electrical signal and the PWM wave; The driving module includes a bridge commutation unit, a current detection unit for detecting a current flowing through the coil, and a driving power supply unit, wherein the bridge commutation unit is used to supply power to the coil; the driving power supply unit supplies power to the coil through the bridge commutation unit; The control module is used to obtain the current flowing through the coil from the current detection unit, and when the current flowing through the coil is greater than a preset value, control the bridge commutation unit to switch the direction of outputting the current to the coil; The current detection unit includes a sampling element and an amplifying circuit. The sampling element is connected in series to a circuit through which the bridge commutation unit supplies power to the coil. The amplifying circuit amplifies the output of the sampling element and transmits it to the control module. The control module is used to calculate the current flowing through the coil based on the output of the amplifying circuit.

2. The handheld relay tester according to claim 1, characterized in that: The coil of the relay to be tested includes a first end and a second end, and the control module controls the bridge commutation unit to output a current from the first end to the second end to the coil, or controls the bridge commutation unit to output a current from the second end to the first end to the coil.

3. The handheld relay tester according to claim 2, characterized in that: One end of the bridge commutation unit is connected to the driving power supply unit, and the other end is connected to the ground terminal of the power supply through the current detection unit.

4. The handheld relay tester according to claim 2, characterized in that: The control module is also used to control the drive power supply unit to increase the voltage output to the bridge commutation unit when the current flowing through the coil is not greater than a preset value and the action electrical signal generated according to the action of the relay to be tested is not received from the contact detection module.

5. The handheld relay tester according to claim 4, characterized in that: The driving power supply unit includes a first voltage unit and a second voltage unit connected to the control module, and the voltage output by the first voltage unit is smaller than the voltage output by the second voltage unit; The control module controls the first voltage unit to supply power to the coil through the bridge commutation unit. If the control module determines that the current flowing through the coil is not greater than a preset value and does not receive an action electrical signal generated according to the action of the relay to be tested from the contact detection module, the control module controls the second voltage unit to supply power to the coil through the bridge commutation unit.

6. The handheld relay tester according to claim 5, characterized in that: The first voltage unit includes a first power supply branch and a switch tube Q5 and a power part K2-A connected in series, and the first power supply branch includes an action switch K6-B coupled to the power part K2-A; when the control module controls the switch tube Q5 to be turned on, the power part K2-A closes the action switch K6-B, so that the first voltage unit outputs voltage to the bridge commutation unit; The second voltage unit includes a second power supply branch and a switch tube Q6 and a power component K3-A connected in series, and the second power supply branch includes an action switch K7-B coupled to the power component K3-A; when the control module controls the switch tube Q6 to turn on, the power component K3-A closes the action switch K7-B so that the second voltage unit outputs voltage to the bridge commutation unit.

7. The handheld relay tester according to claim 2, characterized in that: The bridge commutation unit includes a first switch half-bridge and a second switch half-bridge connected in parallel, the first switch half-bridge includes a switch tube Q10 and a switch tube Q11 connected in series, the second switch half-bridge includes a switch tube Q9 and a switch tube Q12 connected in series, a first end of the coil is connected to the connection between the switch tube Q10 and the switch tube Q11, a second end of the coil is connected to the connection between the switch tube Q9 and the switch tube Q12, and the switch tubes Q10, Q11, Q9 and Q12 are all controlled to be turned on or off by the control module.

8. The handheld relay tester according to claim 7, characterized in that: The switch tube Q10 and the switch tube Q11 are connected to the first driving end of the control module, and the switch tube Q9 and the switch tube Q12 are connected to the second driving end of the control module; The switch tubes Q10 and Q9 are PMOS tubes, and the switch tubes Q11 and Q12 are NMOS tubes; or The switch tubes Q10 and Q9 are NMOS tubes, and the switch tubes Q11 and Q12 are PMOS tubes.

9. The handheld relay tester according to any one of claims 1 to 5, characterized in that: The relay to be tested includes a first group of contacts, and the contact detection module includes a first contact detection unit; the first contact detection unit is used to compare the resistance when the first group of contacts is connected with a preset resistance value, and if the first group of contacts is connected and the resistance when connected is less than the preset resistance value, output an interrupt signal to the control module.

10. The handheld relay tester according to claim 9, characterized in that: The first contact detection unit includes a resistance bridge unit and a first comparison unit, one end of the resistance bridge unit is connected to the positive end of a power supply, and the other end is connected to the ground end of the power supply; the resistance bridge unit includes a first resistance half-bridge and a second resistance half-bridge connected in parallel, the first resistance half-bridge includes a resistor R3 and a resistor R5 connected in series, and the second resistance half-bridge includes a resistor R4 and a resistor R6 connected in series; the first group of contacts is connected to the resistor R3, the resistor R5, the resistor R4 or the resistor R6; The first input end of the first comparison unit is connected between the resistor R3 and the resistor R5 , the second input end of the first comparison unit is connected to the connection between the resistor R4 and the resistor R6 , and the output end IN1 of the first comparison unit is connected to the control module.

11. The handheld relay tester according to claim 10, characterized in that: The resistance bridge unit further includes an adjusting resistor R2 for adjusting a preset resistance value, the first group of contacts is connected in series with the resistor R3, and the adjusting resistor R2 is connected in parallel with the resistor R5.

12. The handheld relay tester according to claim 10, characterized in that: The relay to be tested also includes a second group of contacts, and the contact detection module also includes a second contact detection unit; the second contact detection unit is used to compare the resistance when the second group of contacts is connected with a preset resistance value, and if the second group of contacts is connected and the resistance when connected is less than the preset resistance value, output an interrupt signal to the control module.

13. The handheld relay tester according to claim 12, characterized in that: The second contact detection unit includes a resistor R10, a resistor R9, a resistor R11 and a second comparison unit; one end of the second group of contacts is connected to the resistor R3, and the other end is connected to the ground end of the power supply through the resistor R10, and is connected to the third input end of the second comparison unit, one end of the resistor R9 is connected to the positive end of the power supply, and the other end is connected to the ground end of the power supply through the resistor R11, and is connected to the fourth input end of the second comparison unit, and the output end IN2 of the second comparison unit is connected to the control module.

14. The handheld relay tester according to claim 13, characterized in that: The second contact detection unit further includes an adjusting resistor R8 for adjusting a preset resistance value, and the adjusting resistor R8 is connected in parallel with the resistor R10 or the resistor R9.

15. The handheld relay tester according to any one of claims 1 to 5, characterized in that: It also includes a display screen and a button connected to the control module, the display screen is used to display the test results, as well as the frequency, duty cycle and current test number of the PWM wave, and the button is used to set the frequency, duty cycle and total test number of the PWM wave output by the control module to the drive module.

16. The handheld relay tester according to any one of claims 1 to 5, characterized in that: It also includes a prompt unit connected to the control module, and the prompt unit is used to indicate the action state of the relay to be tested.

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