Printed board test system

Abstract

The invention discloses a printed board test system which comprises a controller, a measuring device, N test channels and a probe branch, the measuring device can be switched between a universal meter mode and a resistance meter mode under the control of the controller, one end of each test channel can be connected with one test point of a tested printed board, and the other end of each test channel can be connected with the probe branch. One end of the probe branch can be connected with the controller, the other end of the probe branch can be connected with the measuring device, each test channel corresponds to each test point of the tested printed board in a one-to-one manner, each test channel is switched on and off under the control of the controller, one end of the probe branch can be connected with one test point of the tested printed board, and the other end of the probe branch can be connected with the measuring device. And the resistance error between the conduction test channel and the tested printed board can be determined, so that the resistance of the part can be eliminated from each test channel, and the accuracy of a test result is ensured. Therefore, automatic testing of the tested printed board is realized, a large amount of manpower and material resources are saved, the testing efficiency is improved, and the accuracy of a testing result can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of printed circuit board testing, and more specifically, to a printed circuit board testing system. Background Art

[0002] As one of the most basic components in the electronics industry, the printed circuit board (PCB) plays an extremely important role in railway signals. With the continuous development of semiconductor design and manufacturing technologies, the number of layers of the printed circuit board has been increasing, and the spacing between components has been decreasing. At the same time, the manufacturing requirements and processing accuracy of the printed circuit board have also been increasing. Therefore, the technical difficulty and complexity of the printed circuit board have reached a very high level at the present stage.

[0003] However, during the production process of the printed circuit board, it is affected by many uncertain factors, such as raw materials, equipment stability, temperature, environment, and human error operations, etc., and will inevitably cause certain defects. In addition, during the production of the printed circuit board, phenomena such as short circuits, virtual soldering, and reverse components may occur during SMT (Surface Mounted Technology) chip mounting, DIP (Dual Inline-pin Package) insertion mounting, or manual soldering. Therefore, testing the printed circuit board has become a necessary process in its manufacturing process.

[0004] Currently, the testing of printed circuit boards is mainly as follows: manually using a multimeter to test each test point of the printed circuit board manually, which has disadvantages such as large workload, slow speed, and low testing efficiency. Summary of the Invention

[0005] In view of this, the present invention discloses a printed circuit board testing system to achieve automatic testing of the printed circuit board to be tested, save a large amount of manpower and material resources, improve testing efficiency, and ensure the accuracy of test results.

[0006] A printed circuit board testing system includes:

[0007] A controller;

[0008] A measuring device, the measuring device is connected to the controller and is used to switch the working mode according to the control instruction sent by the controller, and the working mode includes: multimeter mode and resistance meter mode;

[0009] N test channels, one end of each of the test channels serves as a test end for connecting to a test point of the printed circuit board under test, and the other end of the test channel is used to connect to the positive or negative pole of the measuring device. The control end of the test channel is connected to the controller and is used to conduct or cut off accordingly according to the conduction instruction or disconnection instruction sent by the controller. Wherein, the printed circuit board under test has N connector pins, each of the connector pins serves as one of the test points and corresponds to the test channel one by one, and N is a positive integer;

[0010] A probe branch, one end of the probe branch is used to connect to one of the test points, the other end of the probe branch is connected to the positive pole of the measuring device, and the control end of the probe branch is connected to the controller and is used to conduct when the measuring device is in the ohmmeter mode according to the conduction instruction sent by the controller, so that the measuring device can determine the resistance error between any conductive test channel and the printed circuit board under test.

[0011] Optionally, each of the test channels includes: a first switch, an ammeter, and a second switch;

[0012] One end of the first switch serves as the test end of the test channel for connecting to one of the test points of the printed circuit board under test. The other end of the first switch is connected to the fixed end of the second switch through the ammeter. The control end of the first switch serves as the control end of the test channel and is connected to the controller. The first moving end of the second switch is used to connect to the positive pole of the measuring device, the second moving end is used to connect to the negative pole of the measuring device, and the control end of the second switch is connected to the controller and is used to determine to conduct the first moving end or the second moving end according to the switching instruction sent by the controller.

[0013] Optionally, the probe branch includes: a third switch and a probe. One end of the probe is used to connect to one of the test points, and the other end of the probe is connected to the positive pole of the measuring device through the third switch.

[0014] Optionally, when performing a voltage test or a diode test on the printed circuit board under test, the controller is used to control the measuring device to switch to the multimeter mode.

[0015] Optionally, when performing a resistance test on the printed circuit board under test, the controller is used to control the measuring device to switch to the ohmmeter mode.

[0016] Optionally, when the measuring device switches to the ohmmeter mode, the measuring device measures the resistance using the four-wire method.

[0017] Optionally, when the measuring device measures the resistance by the four-wire method, the measuring device includes: a power supply, an ammeter, a voltmeter, a first resistor, a second resistor, a third resistor, and a fourth resistor;

[0018] The positive pole of the power supply is connected to one end of the resistor under test through the ammeter and the first resistor connected in series in sequence, and the positive pole of the power supply is connected to the other end of the resistor under test through the fourth resistor, where the resistor under test is the resistor in the printed circuit board under test;

[0019] One end of the voltmeter is connected to one end of the resistor under test through the second resistor, and the other end of the voltmeter is connected to the other end of the resistor under test through the third resistor.

[0020] Optionally, each of the test channels has a unique channel number, and each of the channel numbers and each of the connector pins have a one-to-one correspondence.

[0021] Optionally, the controller is further configured to determine the channel number of the test channel that has been conducted based on the probe branch, specifically including:

[0022] Controlling the measuring device to switch to the ohmmeter mode;

[0023] Controlling the conducted channel to be connected to the negative pole of the measuring device;

[0024] Controlling the probe branch to be connected to the positive pole of the measuring device;

[0025] Controlling the probe branch to be connected to the target test point corresponding to the conducted channel, so that the conducted channel, the probe branch, the target test point, and the measuring device form a loop;

[0026] When the measuring device shows a reading, determining the channel number corresponding to the test point, where the channel number is the number pre-set for the conducted channel.

[0027] Optionally, both the first switch and the third switch are relays.

[0028] As can be seen from the above technical solution, the present invention discloses a printed circuit board testing system, including: a controller, a measuring device, N test channels, and a probe branch. The measuring device can be switched between a multimeter mode and a resistance meter mode under the control of the controller. One end of each test channel can be connected to a test point of the printed circuit board to be measured, and the other end can be connected to the measuring device. Each test channel corresponds to a test point of the printed circuit board to be measured one by one. Each test channel is turned on and off under the control of the controller. One end of the probe branch can be connected to a test point of the printed circuit board to be measured, and the other end can be connected to the measuring device, so as to determine the resistance error between the conductive test channel and the printed circuit board to be measured, so as to eliminate this part of the resistance from each test channel and ensure the accuracy of the test result. Therefore, the present invention realizes the automatic testing of the printed circuit board to be measured, saves a large amount of manpower and material resources, improves the test efficiency, and can ensure the accuracy of the test result. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the disclosed drawings without creative efforts.

[0030] Figure 1 It is a circuit schematic diagram of a printed circuit board testing system disclosed in an embodiment of the present invention;

[0031] Figure 2 It is a circuit schematic diagram of another printed circuit board testing system disclosed in an embodiment of the present invention;

[0032] Figure 3 It is a circuit schematic diagram of another printed circuit board testing system disclosed in an embodiment of the present invention;

[0033] Figure 4 It is a structural schematic diagram of a measuring device disclosed in an embodiment of the present invention

[0034] Figure 5 It is a basic circuit schematic diagram of measuring resistance by the four-wire method disclosed in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0036] An embodiment of the present invention discloses a printed circuit board testing system, including: a controller, a measuring device, N test channels, and a probe branch. The measuring device can be switched between a multimeter mode and a resistance meter mode under the control of the controller. One end of each test channel can be connected to a test point of the printed circuit board to be tested, and the other end can be connected to the measuring device. Each test channel corresponds to each test point of the printed circuit board to be tested one by one. Each test channel is turned on and off under the control of the controller. One end of the probe branch can be connected to a test point of the printed circuit board to be tested, and the other end can be connected to the measuring device, so as to determine the resistance error between the turned-on test channel and the printed circuit board to be tested, so as to eliminate this part of the resistance from each test channel and ensure the accuracy of the test result. Therefore, the present invention realizes the automatic testing of the printed circuit board to be tested, saves a large amount of manpower and material resources, improves the test efficiency, and can ensure the accuracy of the test result.

[0037] See Figure 1 , the circuit schematic diagram of a printed circuit board testing system disclosed in an embodiment of the present invention. The printed circuit board testing system includes: a controller ( Figure 1 not shown in the figure), a measuring device 10, N test channels 20, and a probe branch 30.

[0038] Among them, the measuring device 10 is connected to the controller and is used to switch the working mode according to the control instruction sent by the controller. The working modes include: a multimeter mode and a resistance meter mode.

[0039] In practical applications, when it is necessary to test the voltage and diode of the printed circuit board to be tested, the controller can control the measuring device 10 to switch to the multimeter mode. When it is necessary to measure the resistance in the printed circuit board to be tested, especially the resistance with high precision requirements, the controller can control the measuring device 10 to switch to the resistance meter mode.

[0040] Of course, for the impedance with low precision requirements, the controller can also control the measuring device 10 to switch to the multimeter mode.

[0041] One end of each test channel 20 serves as a test end for connecting to a test point of the printed circuit board to be tested. The other end of the test channel 20 is used to connect to the positive or negative pole of the measuring device 10. The control end of the test channel 20 is connected to the controller and is used to perform corresponding conduction or disconnection according to the conduction instruction or disconnection instruction sent by the controller.

[0042] Among them, the printed circuit board to be tested has N connector pins. Each connector pin serves as a test point and corresponds to the test channel 20 one by one. N is a positive integer.

[0043] It should be noted that, generally, the printed circuit board does not work independently. It needs to be connected to the external communication through the connector interface and transmit signals through the connector interface. Therefore, connectors for external communication are provided on the vast majority of printed circuit boards. Each connector has one or more connector pins. By connecting to the connector pins, the performance test of the printed circuit board can be carried out. In this embodiment, the printed circuit board under test has N connector pins, and each connector pin serves as a test point. By connecting the test channel 20 to the connector pins, the connection between the printed circuit board test system and the printed circuit board under test can be achieved, so as to realize the performance test of the printed circuit board under test by the printed circuit board test system.

[0044] In practical applications, the number of test channels 20 in the printed circuit board test system is the same as the number of connector pins of the printed circuit board under test, both are N, and N is a positive integer, such as N = 96. Or rather, the channel numbers of the test channels 20 and the connector pins are in a one-to-one correspondence relationship, so as to convert the connection relationship between the test points to be tested on the printed circuit board under test into the connection relationship of the corresponding test channels 20.

[0045] In this embodiment, one end of the probe branch 30 is used to connect to a test point of the printed circuit board under test, the other end of the probe branch 30 is connected to the positive pole of the measuring device 10, and the control end of the probe branch 30 is connected to the controller, and is used to conduct when the measuring device 10 is in the ohmmeter mode according to the conduction instruction sent by the controller, so that the measuring device 10 can determine the resistance error between any conducting test channel and the printed circuit board under test.

[0046] In practical applications, when the printed circuit board test system is communicatively connected to the printed circuit board under test, there is a certain resistance value in the connection cable and connector provided between the printed circuit board test system and the printed circuit board under test, and this resistance value will affect the measurement result of the printed circuit board test system on the printed circuit board under test. Based on this, when the present invention uses the probe branch 30 to conduct a conduction test, the resistance of the connection cable and connector part (i.e., the error resistance of the printed circuit board under test) is measured through the probe branch 30, and the resistance of this part on each test channel 20 is eliminated, so as to ensure the accuracy of the test result.

[0047] In summary, the present invention discloses a printed circuit board testing system, including: a controller, a measuring device 10, N test channels 20, and a probe branch 30. The measuring device 10 can be switched between a multimeter mode and a resistance meter mode under the control of the controller. One end of each test channel 20 can be connected to a test point of the printed circuit board to be tested, and the other end can be connected to the measuring device 10. Each of the test channels 20 corresponds to a respective test point of the printed circuit board to be tested. Each test channel 20 is turned on and off under the control of the controller. One end of the probe branch 30 can be connected to a test point of the printed circuit board to be tested, and the other end can be connected to the measuring device 10, so as to determine the resistance error between the conductive test channel and the printed circuit board to be tested, so as to eliminate this part of the resistance from each test channel 20 and ensure the accuracy of the test result. Therefore, the present invention realizes the automatic testing of the printed circuit board to be tested, saves a large amount of manpower and material resources, improves the test efficiency, and can ensure the accuracy of the test result.

[0048] To further optimize the above embodiment, refer to Figure 1 , each test channel 20 includes: a first switch S1, an ammeter A, and a second switch S2.

[0049] One end of the first switch S1 serves as the test end of the test channel 20 and is used to connect to a test point of the printed circuit board to be tested. The other end of the first switch S1 is connected to the fixed end of the second switch S2 through the ammeter A. The control end of the first switch S1 serves as the control end of the test channel 20 and is connected to the controller. The first moving end of the second switch S2 is used to connect to the positive pole of the measuring device 10, and the second moving end is used to connect to the negative pole of the measuring device 10. The control end of the second switch S2 is connected to the controller and is used to determine to conduct the first moving end or the second moving end according to the switching instruction sent by the controller.

[0050] In practical applications, when there is a reading on the ammeter A on the test channel 20, it can be determined that there is current passing through this test channel 20.

[0051] When testing the printed circuit board to be tested, the process of forming a loop between the printed circuit board testing system and the printed circuit board to be tested is Figure 1 illustrated by taking channel 1 and channel 2 among the N test channels 20 as examples as follows:

[0052] Channel 1 is pre-corresponded and connected to test point 1 in the printed circuit board to be tested, and channel 2 is pre-corresponded and connected to test point 2 in the printed circuit board to be tested.

[0053] When testing the printed circuit board under test, the first switch S1 in channel 1 is turned on under the control of the controller, and the second switch S2 is connected to the positive pole of the measuring device 10 under the control of the controller. The first switch in channel 2 is turned on under the control of the controller, and the second switch S2 is connected to the negative pole of the measuring device 10 under the control of the controller. The measuring device 10 is switched to the ohmmeter mode under the control of the controller.

[0054] The test point 1 is accessed through channel 1, passes through the first switch S1 and the second switch S2 in channel 1, and is connected to the positive pole of the measuring device 10. Then, through the measuring device 10 in the ohmmeter mode and the first switch S1 and the second switch S2 in channel 2, it reaches the test point 2. Thus, a loop is formed between the test point 1 and the test point 2.

[0055] Preferably, the first switch S1 can be a relay, and the second switch S2 can be a single-pole double-throw switch.

[0056] To further optimize the above embodiment, refer to Figure 1 , the probe branch 30 can include: a third switch S3 and a probe 31.

[0057] One end of the probe 31 is used to connect to a test point on a printed circuit board under test, and the other end of the probe 31 is connected to the positive pole of the measuring device 10 through the third switch S3.

[0058] Preferably, the third switch S3 can be a relay.

[0059] In the present invention, each connector pin of the printed circuit board under test and each test channel 20 have a one-to-one correspondence. To facilitate the distinction of each test channel 20, the present invention assigns a channel serial number to each test channel, that is, each test channel 20 has a unique channel serial number. At the same time, each connector pin of the printed circuit board under test also has a corresponding number, so as to realize a one-to-one correspondence between each channel serial number and each connector pin of the printed circuit board under test.

[0060] In practical applications, when the printed circuit board test system first establishes a connection with the printed circuit board under test, the automatic test system in the controller does not know the correspondence between each connector pin of the printed circuit board under test and each test channel 20. Based on this, the present invention adds a probe branch 30 to the printed circuit board test system, and uses the probe branch 30 to determine the correspondence between each channel serial number and the connector pin, so that when performing a continuity test on each connector pin, the target channel serial number corresponding to the connector pin can be determined.

[0061] Therefore, the controller is also used to determine the channel serial number of the test channel that has been conducted based on the probe branch 30. The specific process includes:

[0062] Controlling the measuring device 10 to switch to the ohmmeter mode;

[0063] Control the connection of the conducting channel to the negative electrode of the measuring device 10;

[0064] Control the probe branch 30 to connect to the positive electrode of the measuring device 10;

[0065] Control the probe branch 30 to connect to the target test point corresponding to the conducting channel, so that the conducting channel, the probe branch, the target test point, and the measuring device 10 form a loop;

[0066] When the measuring device 10 shows a reading, determine the channel number corresponding to the test point, and this channel number is the number pre-set for the conducting channel.

[0067] Illustrate the principle of using the probe branch 30 to determine the conducting channel number as follows:

[0068] The working mode of the measuring device 10 is the ohmmeter mode. The first switch S1 of any test channel 20 is closed, the second switch S2 of this test channel 20 is connected to the negative electrode of the measuring device 10, the third switch S3 is closed, the probe branch 30 is connected to the positive electrode of the measuring device 10, and by connecting the probe 31 to the target test point connected to this test channel, a loop is formed for the test channel 20 corresponding to the target test, and a reading appears on the measuring device 10 in the ohmmeter mode, thereby determining the channel number corresponding to the target test point.

[0069] It can be understood that when using the probe branch 30 to determine the correspondence between each test point (i.e., connector pin) in the printed circuit board under test and the channel number of the test channel 20, when testing the printed circuit board under test, the mapping relationship between the two currently tested test points can be determined, that is, the two test points connected in the current test loop.

[0070] Illustrate, when determining the mapping relationship between test point 1 and test point 2, the first switch S1 in the test channel 20 corresponding to test point 1 and the first switch S1 in the test channel 20 corresponding to test point 2 are both closed, the second switch S2 corresponding to test point 1 and the second switch S2 corresponding to test point 2 are respectively connected to the positive electrode and the negative electrode of the measuring device 10, thereby forming a test loop to realize the construction of the mapping relationship between test point 1 and test point 2.

[0071] In practical applications, it is possible to set the test channel with a smaller channel number to connect to the positive electrode of the measuring device 10, and the test channel with a larger channel number to connect to the negative electrode of the measuring device 10.

[0072] When the electrical component to be tested in the printed circuit board under test is a diode, the positive and negative poles of the measuring device 10 connected to the test channel lock may need to be reversed, that is, the test channel with a smaller channel number is connected to the negative pole of the measuring device 10, and the test channel with a larger channel number is connected to the positive pole of the measuring device 10, which is specifically determined according to actual needs.

[0073] In this embodiment, the automatic test software in the controller can establish a mapping between multiple test points, and set the impedance, voltage, or diode range for different mappings according to the test plan, so as to complete the test plan.

[0074] Specifically, when the controller performs a test through the established mapping, it calls the switch on the corresponding test channel to turn it on, and calls the switch on the required impedance or voltage or diode line to select and turn it on to obtain a test reading, and compares the test reading with the set range value. If it meets the requirement, the test passes; otherwise, the test fails.

[0075] It should be particularly noted that when performing a voltage test or a diode test on the printed circuit board under test, the controller is used to control the measuring device to switch to the multimeter mode. See Figure 2 the circuit schematic diagram of another printed circuit board test system shown in Figure 2 where the measuring device 10 is a multimeter.

[0076] When performing a resistance test on the printed circuit board under test, the controller is used to control the measuring device to switch to the resistance meter mode. See Figure 3 the circuit schematic diagram of another printed circuit board test system shown in Figure 3 where the measuring device 10 is a resistance meter.

[0077] See Figure 4 the structural schematic diagram of a measuring device disclosed in the embodiment of the present invention. The measuring device 10 realizes the switching between a multimeter and a resistance meter through the switch S.

[0078] Currently, when using the two-wire method to measure resistance, according to Ohm's law R = U / I, whether measuring the resistance value at a short distance or a long distance, the measurement result will be affected by the wire resistance, resulting in a voltage drop. The voltage drop (voltage decrease) caused by the longer wire during long-distance measurement is greater and has a non-negligible impact. In actual measurement, due to certain conditions, it is only possible to measure the voltage at a long distance. At this time, due to the large current flowing through the long wire during long-distance measurement, an unignorable voltage drop is caused, which affects the measurement of the resistance value.

[0079] Based on this, when the present invention tests the resistance, in order to ensure the accuracy of the resistance test value, the measuring device 10 uses the four-wire method to measure the resistance.

[0080] When measuring with the four-wire method, the additional wires are led to the voltmeter, which can avoid the influence of the voltage drop caused by the wire resistance during the measurement of the resistance. Since the internal resistance of the voltmeter is extremely large, the current flowing through the voltmeter is negligible compared to the current flowing through the resistance to be measured. Therefore, the voltage drop generated by the additional wires will not affect the measurement result. At this time, the ratio of the measured voltage to the current measured by the ammeter can be approximately regarded as the resistance value of the resistance to be measured. The voltage difference generated by the wire resistance is almost zero and does not affect the voltage measurement result. Since only a very small part of the current (negligibly small) flows through the voltmeter, it also does not affect the current measurement result. The resistance to be measured is a low resistance, and it can also be accurately measured.

[0081] For ease of understanding, refer to Figure 5 , a basic circuit schematic diagram for measuring resistance by the four-wire method disclosed in an embodiment of the present invention, where Figure 5 what is shown in Figure 4 is the resistor meter structure in

[0082] The positive pole of the power supply VCC is connected to one end of the resistance Rx to be measured through the ammeter A and the first resistor R1 connected in series in sequence. The positive pole of the power supply VCC is connected to the other end of the resistance Rx to be measured through the fourth resistor R4, where the resistance Rx to be measured is the resistance in the printed circuit board to be measured;

[0083] One end of the voltmeter V is connected to one end of the resistance Rx to be measured through the second resistor R2, and the other end of the voltmeter V is connected to the other end of the resistance Rx to be measured through the third resistor R3.

[0084] In this embodiment, the voltmeter V is directly connected to both ends of the resistance Rx to be measured by skipping the first resistor R1 and the second resistor R2 through a cable. The measured voltage is the voltage directly divided on the resistance Rx to be measured. Then, the current in the circuit is measured through the ammeter A, so that the true resistance value of the resistance Rx to be measured can be measured.

[0085] Compared with the lead wires led out by the existing multimeter, the voltage value measured in this embodiment is the voltage jointly divided by the two lead wires (R1, R2) and Rx. Then, the current in the circuit is measured through the ammeter A, and the resistance obtained by dividing the voltage by the current is the sum of R1, R2, and Rx.

[0086] It should be particularly noted that Figure 4 the reference numeral A in Figure 1 corresponds to the “+” on the measuring device 10 in Figure 4 the reference numeral B in Figure 1 corresponds to the “—” below the measuring device 10 in

[0087] In summary, the printed circuit board testing system disclosed in the present invention not only reduces the time and cost required for manual testing of printed circuit boards, eliminates the resistance error caused by the connector end, and adopts the four-wire measurement technology to improve the testing accuracy, but also when multiple test points independently set the test mapping, it can transfer a variety of connectors, is applicable to printed circuit boards with different test requirements, and enhances its applicability.

[0088] It should also be noted that when testing different printed circuit boards, the following testing process can be adopted:

[0089] Make a mating connector (i.e., the automatic testing software) for the connectors of different printed circuit boards, connect the mating connector to the printed circuit board testing system, and call the printed circuit board testing scheme through the following program, input the production order number, board serial number, temperature, and humidity, and test the printed circuit board and generate a test report.

[0090] The following is the program for calling and generating the report:

[0091] var s = wire.prompt("Production order number", true, "");

[0092] Wire.setKeyValue("process", s);

[0093] Wire.speak("Start testing");

[0094] Wire.run("Printed circuit board name");

[0095] Wire.speak("Testing ended");

[0096] / / Wire.mergeReport();

[0097] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0098] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0099] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A printed circuit board testing system, characterized in that, it includes: A controller; A measuring device, which is connected to the controller and is used to switch the working mode according to the control instruction sent by the controller. The working modes include: multimeter mode and ohmmeter mode; N test channels, one end of each test channel serves as a test end for connecting to a test point of the printed circuit board to be tested, and the other end of the test channel is used to connect to the positive or negative pole of the measuring device. The control end of the test channel is connected to the controller and is used to conduct or cut off correspondingly according to the conduction instruction or disconnection instruction sent by the controller; wherein, the printed circuit board to be tested has N connector pins, each connector pin serves as one of the test points and corresponds to the test channel one by one, and N is a positive integer; A probe branch, one end of the probe branch is used to connect to one of the test points, the other end of the probe branch is connected to the positive pole of the measuring device, and the control end of the probe branch is connected to the controller and is used to conduct when the measuring device is in the ohmmeter mode according to the conduction instruction sent by the controller, so that the measuring device can determine the resistance error between any conductive test channel and the printed circuit board to be tested.

2. The printed circuit board testing system according to claim 1, characterized in that, each test channel includes: a first switch, an ammeter and a second switch; One end of the first switch serves as the test end of the test channel for connecting to one of the test points of the printed circuit board to be tested. The other end of the first switch is connected to the fixed end of the second switch through the ammeter. The control end of the first switch serves as the control end of the test channel and is connected to the controller. The first moving end of the second switch is used to connect to the positive pole of the measuring device, the second moving end is used to connect to the negative pole of the measuring device, and the control end of the second switch is connected to the controller and is used to determine to conduct the first moving end or the second moving end according to the switching instruction sent by the controller.

3. The printed circuit board testing system according to claim 2, characterized in that, the probe branch includes: a third switch and a probe, one end of the probe is used to connect to one of the test points, and the other end of the probe is connected to the positive pole of the measuring device through the third switch.

4. The printed circuit board testing system according to claim 1, characterized in that, when performing voltage testing or diode testing on the printed circuit board to be tested, the controller is used to control the measuring device to switch to the multimeter mode.

5. The printed circuit board testing system according to claim 1, characterized in that, when performing resistance testing on the printed circuit board to be tested, the controller is used to control the measuring device to switch to the ohmmeter mode.

6. The printed circuit board testing system according to claim 5, characterized in that, when the measuring device switches to the ohmmeter mode, the measuring device measures resistance by the four-wire method.

7. The printed circuit board testing system according to claim 6, characterized in that, When the measuring device measures the resistance by the four-wire method, the measuring device includes: a power supply, an ammeter, a voltmeter, a first resistor, a second resistor, a third resistor, and a fourth resistor; The positive pole of the power supply is connected to one end of the resistor under test through the ammeter and the first resistor connected in series in sequence, and the positive pole of the power supply is connected to the other end of the resistor under test through the fourth resistor, where the resistor under test is the resistor in the printed circuit board under test; One end of the voltmeter is connected to one end of the resistor under test through the second resistor, and the other end of the voltmeter is connected to the other end of the resistor under test through the third resistor.

8. The printed circuit board test system according to claim 1, characterized in that, Each of the test channels has a unique channel number, and each of the channel numbers and each of the connector pins are in one-to-one correspondence.

9. The printed circuit board test system according to claim 1, characterized in that, The controller is further configured to determine the channel number of the already-conducted test channel based on the probe branch, specifically including: Controlling the measuring device to switch to the ohmmeter mode; Controlling the already-conducted channel to be connected to the negative pole of the measuring device; Controlling the probe branch to be connected to the positive pole of the measuring device; Controlling the probe branch to be connected to the target test point corresponding to the already-conducted channel, so that the already-conducted channel, the probe branch, the target test point, and the measuring device form a loop; When the measuring device shows a reading, determining the channel number corresponding to the test point, and the channel number is the number set in advance for the already-conducted channel.

10. The printed circuit board test system according to claim 3, characterized in that, Both the first switch and the third switch are relays.

Images