Detection device for control system

Abstract

The embodiment of the invention relates to detection equipment for a control system. The detection device comprises a first voltage detection unit, the input end of the first voltage detection unit is electrically connected with a detected object related to the control system, and the first voltage detection unit is configured to output a first detection voltage; the current output end of the excitation current source is electrically connected with one end of the first resistor and the input end of the second voltage detection unit; a second voltage detection unit configured to output a second detection voltage; the other end of the first resistor is electrically connected with the input end of the first voltage detection unit; and the control unit is configured to control the excitation current source to output the excitation current so as to determine a resistance detection value of the detected object according to the first detection voltage, the second detection voltage and the first resistance. The detection equipment can realize high-efficiency detection.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of detection of control systems, and more particularly to a detection device for a control system. Background Art

[0002] At present, fault diagnosis of control systems is mainly achieved through multimeters, which requires operators to perform point-to-point testing. This method has disadvantages such as missing test points or repeated collection, and the test efficiency is not high. At the same time, the multimeter equipment does not have intelligent auxiliary functions, and the operator is required to manually select the detection mode and detection range according to the on-site working conditions, and manually judge the health of the control system. In addition, the multimeter equipment cannot perform the control system fault prediction function. For example, most of the existing control systems can only realize on-site fault diagnosis through multimeters. This point-to-point testing method has disadvantages such as missing test points or repeated collection, and the test efficiency is not high; using a multimeter to diagnose control system faults does not have intelligent auxiliary functions, and requires operators to manually select the detection mode and detection range according to the current working conditions. At the same time, the operator is required to manually judge the measurement results, which is prone to misjudgment of on-site working conditions due to irregular operations. Summary of the invention

[0003] In view of the above problems, the present disclosure provides a detection device for a control system, which can significantly improve the test efficiency.

[0004] According to one aspect of the present disclosure, a detection device for a control system is provided. The detection device includes: a first voltage detection unit, the input end of the first voltage detection unit is electrically connected to the object under test of the control system, and the first voltage detection unit is configured to output a first detection voltage; an excitation current source, the current output end of the excitation current source is electrically connected to one end of the first resistor and the input end of the second voltage detection unit; a second voltage detection unit, the second voltage detection unit is configured to output a second detection voltage; a first resistor, the other end of the first resistor is electrically connected to the input end of the first voltage detection unit; and a control unit, which is configured to control the excitation current source to output an excitation current, so as to determine the resistance detection value of the object under test according to the first detection voltage, the second detection voltage and the first resistor, and determine that the object under test is abnormal in response to determining that the resistance detection value of the object under test deviates from the predetermined normal resistance value by more than a first predetermined range.

[0005] In some embodiments, the control unit is also configured to control the excitation current source to stop outputting the excitation current so as to determine the output voltage value of the object under test based at least on the first detection voltage, and to determine that the object under test is abnormal in response to determining that the output voltage value of the object under test deviates from a predetermined normal voltage value by exceeding a second predetermined range; the object under test includes an input and output interface of the control system.

[0006] In some embodiments, the first voltage detection unit includes: a first voltage follower, the input end of the first voltage follower is configured as the input end of the first voltage detection unit; and a first voltage divider unit, the input end of the first voltage divider unit is electrically connected to the output end of the first voltage follower, and the output end of the first voltage divider unit is used to output a first detection voltage; the control unit is also configured to: determine the output voltage value of the object under test based on at least the first detection voltage and the voltage divider ratio of the first voltage divider unit.

[0007] In some embodiments, the control unit is configured to: control the excitation current source to output an excitation current having a first predetermined current value so as to determine a resistance detection value of the object under test relative to the first predetermined current value, the first predetermined current value corresponding to a first resistance range, and in response to determining that the resistance detection value is greater than an upper limit of the first resistance range, control the excitation current source to output an excitation current having a second predetermined current value, the second predetermined current value being greater than the first predetermined current value.

[0008] In some embodiments, the resistance detection value is within a second resistance range corresponding to a second predetermined current value.

[0009] In some embodiments, the control unit is further configured to: in response to determining that the output voltage value of the object under test is less than a predetermined voltage threshold, control the excitation current source to output an excitation current so as to determine the resistance detection value of the object under test.

[0010] In some embodiments, the detection device also includes: a self-detection resistor, one end of which is electrically connected to one end of the first switch; and a first switch, the other end of which is electrically connected to the other end of the first resistor; the control unit is also configured to: disconnect the detection device from the object under test, close the first switch, and control the excitation current source to output the excitation current, so as to determine whether the detection device has an internal fault based on the first detection voltage, the second detection voltage and the first resistor.

[0011] In some embodiments, the control unit is further configured to generate a fitting curve about the resistance detection value of the object under test according to historical sampling values ​​of the resistance detection value of the object under test.

[0012] In some embodiments, the control unit is further configured to: predict the decay period of the resistance detection value of the measured object according to the fitting curve, the decay period being the time it takes for the resistance detection value of the measured object to decay from the rated value to deviate from the rated value by more than a predetermined threshold.

[0013] In some embodiments, the second voltage detection unit includes: a second voltage follower, the input end of the second voltage follower is configured as the input end of the second voltage detection unit; and a second voltage divider unit, the input end of the second voltage divider unit is electrically connected to the output end of the second voltage follower, and the output end of the second voltage divider unit is used to output the second detection voltage; the control unit is also configured to: determine the resistance detection value of the object under test based on the first detection voltage, the voltage divider ratio of the first voltage divider unit, the second detection voltage, the voltage divider ratio of the second voltage divider unit and the first resistance.

[0014] According to the scheme of the present disclosure, the control unit controls the excitation current source to output the excitation current, the first voltage detection unit detects the first detection voltage about the first resistor, the second voltage detection unit detects the second detection voltage about the object under test, and the control unit determines the resistance detection value of the object under test based on the first detection voltage, the second detection voltage and the first resistor, thereby achieving efficient detection.

[0015] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements.

[0017] Figure 1 A schematic diagram showing the connection between a detection device for controlling a system and a control system according to an embodiment of the present disclosure is shown.

[0018] Figure 2 A schematic structural diagram of a detection device for controlling a system according to an embodiment of the present disclosure is shown.

[0019] Figure 3 The equivalent circuit of the detection device according to the embodiment of the present disclosure when performing voltage detection is shown.

[0020] Figure 4 A schematic diagram showing a detection device according to an embodiment of the present disclosure when performing a self-test is shown.

[0021] Figure 5 A schematic diagram showing multiple measuring ranges of a detection device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0023] As used herein, the term "including" and its variations mean open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0024] As described above, the fault diagnosis of the current control system is mainly achieved through a multimeter, which requires operators to perform point-to-point testing. This method has disadvantages such as missing test points or repeated collection, and the test efficiency is not high. At the same time, the multimeter device does not have intelligent auxiliary functions, and the operator is required to manually select the detection mode and detection range according to the on-site working conditions and manually judge the health of the control system. In addition, the multimeter device cannot perform the control system fault prediction function. Therefore, the prior art has the following deficiencies: (1) Most existing control systems can only perform on-site fault diagnosis through a multimeter. This point-to-point testing method has disadvantages such as missing test points or repeated collection, and the test efficiency is low; (2) Using a multimeter to diagnose control system failures does not have intelligent auxiliary functions. The operator is required to manually select the detection mode and detection range according to the current working conditions. At the same time, the operator is required to make manual judgments on the measurement results, which is prone to misjudgment of the on-site working conditions due to irregular operations; (3) Traditional testing methods are unable to record data. Existing data and historical data can only be recorded and compared manually, which has disadvantages such as low efficiency and prone to errors.

[0025] In order to at least partially solve one or more of the above problems and other potential problems, an exemplary embodiment of the present disclosure proposes a detection device for a control system. According to the scheme of the present disclosure, a control unit controls an excitation current source to output an excitation current, a first voltage detection unit detects a first detection voltage about a first resistor, a second voltage detection unit detects a second detection voltage about a measured object, and the control unit determines a resistance detection value of the measured object according to the first detection voltage, the second detection voltage and the first resistor, thereby achieving efficient detection.

[0026] Figure 1 The connection diagram of the detection device 100 and the control system 200 for the control system of the embodiment of the present disclosure is shown. The control system 200, for example, includes a controller 202 and a field instrument 204. The controller 202 can be implemented, for example, by a PLC (programmable logic controller). The controller 202 transmits data with the field instrument 204 through its input and output (I / O) interface. The detection interface of the detection device 100 is electrically connected to the input and output interface of the controller 202 of the control system 200, so as to detect the control system 200. The detection interface of the detection device 100 and the input and output interface of the controller 202 of the control system 200 can be electrically connected, for example, through an acquisition cable. The detection device 100 can be provided with a multi-channel acquisition circuit, and the multi-channel acquisition circuit has a similar structure, each acquisition circuit has a detection interface, and each detection interface is electrically connected to an input and output interface of the control system 200, so as to detect the input and output interface.

[0027] Figure 2 FIG. 1 is a schematic diagram showing a structure of a detection device 100 for controlling a system according to an embodiment of the present disclosure. Figure 2 1 shows the structure of one acquisition circuit in the detection device 100, and the other acquisition circuits of the detection device 100 have the same or similar circuit structure. Among them, the detection interface P1 is used to electrically connect with the object under test of the control system 200 to collect signals. For the convenience of explanation, the object under test of the control system 200 is represented by RX.

[0028] The detection device 100 includes a first voltage detection unit 102, an excitation current source 106, a second voltage detection unit 104, a first resistor R1, and a control unit 108. The input end of the first voltage detection unit 102 is electrically connected to the object under test of the control system 200, and the first voltage detection unit 102 is configured to output a first detection voltage u c1 The current output terminal of the excitation current source 106 is electrically connected to one end of the first resistor R1 and the input terminal of the second voltage detection unit 104. The second voltage detection unit 104 is configured to output a second detection voltage u c2 The other end of the first resistor R1 is electrically connected to the input end of the first voltage detection unit 102. The control unit is electrically connected to the first voltage detection unit 102, the excitation current source 106, and the second voltage detection unit 104. The control unit 108 is configured to control the excitation current source 106 to output an excitation current so as to generate an excitation current according to the first detection voltage u c1 , the second detection voltage u c2And the first resistor R1 determines the resistance detection value of the object under test. The detection device 100, for example, also includes a self-test resistor R6 and a first switch K1. One end of the self-test resistor R6 is electrically connected to one end of the first switch K1, and the other end of the first switch K1 is electrically connected to the other end of the first resistor R1. In the process of detecting the control system 200, the control unit 108 controls the first switch K1 to be in an off state, so that the self-test resistor R6 is disconnected. It is worth noting that the control unit 108 also compares the resistance detection value of the object under test with a pre-stored predetermined normal resistance value. If the resistance detection value of the object under test deviates from the predetermined normal resistance value by more than a first predetermined range, the control unit 108 determines that the object under test is abnormal; otherwise, the control unit 108 determines that the object under test is normal. The first predetermined range can be reasonably set according to the specific application scenario. In some embodiments, the first predetermined range is, for example, 10%.

[0029] It should be understood that the measured object of the control system 200 includes the input and output interfaces of the control system 200. The control unit 108 can be implemented based on MCU (microprocessing unit), CPU (central processing unit), FPGA (field programmable gate array), PLC, etc.

[0030] The first voltage detection unit 102 includes, for example, a first voltage follower and a first voltage divider 122. The input end of the first voltage follower is configured as the input end of the first voltage detection unit 102. The input end of the first voltage divider 122 is electrically connected to the output end of the first voltage follower, and the output end of the first voltage divider 122 is configured to output a first detection voltage u c1 .

[0031] The first voltage follower is implemented based on the first operational amplifier U1, for example. The non-inverting input terminal of the first operational amplifier U1 is configured as the input terminal of the first voltage follower, and the output terminal of the first operational amplifier U1 is electrically connected to the inverting input terminal of the first operational amplifier U1.

[0032] The first voltage divider unit 122 includes a second resistor R2 and a third resistor R3. The second resistor R2 and the third resistor R3 are connected in series. One end of the second resistor R2 is configured as the input end of the first voltage divider unit 122; the other end of the second resistor R2 is electrically connected to one end of the third resistor R3 and is configured as the output end of the first voltage divider unit 122; the other end of the third resistor R3 is grounded.

[0033] The second voltage detection unit 104 includes a second voltage follower and a second voltage divider unit 142. The input end of the second voltage follower is configured as the input end of the second voltage detection unit 104. The input end of the second voltage divider unit 142 is electrically connected to the output end of the second voltage follower, and the output end of the second voltage divider unit 142 is configured to output a second detection voltage u c2.

[0034] The second voltage follower is implemented based on the second operational amplifier U2, for example. The non-inverting input terminal of the second operational amplifier U2 is configured as the input terminal of the second voltage follower, and the output terminal of the second operational amplifier U2 is electrically connected to the inverting input terminal of the second operational amplifier U2.

[0035] The second voltage divider unit 142 includes a fourth resistor R4 and a fifth resistor R5. The fourth resistor R4 and the fifth resistor R5 are connected in series. One end of the fourth resistor R4 is configured as the input end of the second voltage divider unit 142; the other end of the fourth resistor R4 is electrically connected to one end of the fifth resistor R5 and is configured as the output end of the second voltage divider unit 142; the other end of the fifth resistor R5 is grounded.

[0036] Based on the detection device 100, it is possible to detect the resistance value of the object RX under test related to the control system 200, and it is also possible to detect the output voltage value of the object RX under test related to the control system 200. It is also possible to determine whether the control system 200 has a fault based on the detected resistance value of the object RX under test related to the control system 200 and the output voltage value of the object RX under test related to the control system 200.

[0037] For example, the detection device 100 can detect the resistance value of the object RX under test related to the control system 200. During the detection process, the control unit 108 controls the excitation current source 106 to output the excitation current i in At the same time, the first voltage detection unit 102 detects and outputs a first detection voltage u of the object under test RX. c1 The second voltage detection unit 104 detects and outputs a second detection voltage u about the first resistor R1 c2 .

[0038] The control unit 108 detects the first voltage u c1 Determine a first voltage u1 about the object under test RX. The first voltage u1 about the object under test RX is, for example, based on the excitation current i in The voltage generated on the object under test RX. It should be understood that the first voltage u1 of the object under test RX is also the voltage received by the input end of the first voltage detection unit 102. Referring to the specific structure of the first voltage detection unit 102, it can be determined that the first voltage u1 of the object under test RX can be represented by the following formula (1): (1) That is, the control unit 108 can detect the first voltage u c1And the voltage division ratio of the first voltage division unit 122 determines the first voltage u1 about the measured object RX. Wherein, R3 represents the resistance value of the third resistor R3, and R2 represents the resistance value of the second resistor R2.

[0039] The control unit 108 detects the second voltage u c2 Determine a second voltage u2 about the first resistor R1. The second voltage u2 about the first resistor R1 is, for example, based on the excitation current i in The sum of the voltages generated on the first resistor R1 and the object under test RX, the second voltage u2 about the first resistor R1 is the voltage at one end of the first resistor R1, that is, the voltage received at the input end of the second voltage detection unit. Referring to the specific structure of the second voltage detection unit 104, it can be determined that it can be represented by the following formula (2): (2) That is, the control unit 108 can detect the second voltage u c2 The voltage division ratio of the second voltage division unit 142 determines the second voltage u2 about the first resistor R1. R4 represents the resistance value of the fourth resistor R4, and R5 represents the resistance value of the fifth resistor R5.

[0040] It should be understood that the difference between the second voltage u2 of the first resistor R1 and the first voltage u1 of the measured object RX is based on the excitation current i in Therefore, the control unit 108 determines the resistance value R of the object RX according to the second voltage u2 of the first resistor R1, the first voltage u1 of the object RX and the first resistor R1. X , refer to the following formula (3) for details: (3) Among them, R X The resistance value of the measured object RX is represented, and R1 represents the resistance value of the first resistor R1.

[0041] Substituting the above formula (1) and formula (2) into formula (3), it can be seen that the control unit 108 can be used according to the first detection voltage u c1 , the voltage division ratio of the first voltage division unit 122, the second detection voltage u c2 , the voltage division ratio of the second voltage division unit 142 and the first resistor R1 determine the resistance value of the measured object RX.

[0042] It is worth noting that the excitation current generated by the excitation current source 106 can be used to generate an excitation current to implement the resistance sampling technology. The excitation current will not be conducted to the inside of the module, that is, when the detection device 100 performs the resistance acquisition function, it will not be disturbed by the internal resistance of the module, thus ensuring the accuracy of resistance acquisition.

[0043] Among them, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the self-test resistor R6 are all high-precision resistors with an error coefficient lower than 0.1% and a temperature coefficient lower than ±5ppm / °C.

[0044] The control unit 108 further includes an analog-to-digital conversion unit (ADC), and the control unit 108 receives the first detection voltage u based on the analog-to-digital conversion unit. c1 And the second detection voltage u c2 , the analog-to-digital conversion unit converts the first detection voltage u c1 And the second detection voltage u c2 The digital signal is converted into a digital signal and transmitted to a main control unit such as an MCU in the control unit 108 , and the main control unit calculates and obtains the resistance value of the measured object RX.

[0045] The control unit 108 can determine whether the control system 200 has a fault according to the resistance value of the measured object RX obtained by detection. For example, if the resistance value of the measured object RX obtained by detection is close to 0, the control unit 108 can determine that there is a short circuit fault between the input and output interface of the control system 200 and the external instrument. If the resistance value of the measured object RX obtained by detection is very large, far exceeding the predetermined resistance value, or close to infinity, the control unit 108 can determine that there is an open circuit fault between the input and output interface of the control system 200 and the external instrument.

[0046] The detection device 100 can detect the output voltage value of the object RX of the control system 200. When performing voltage detection, the control unit 108 controls the excitation current source 106 to stop outputting the excitation current i in . Figure 3 FIG. 1 shows an equivalent circuit of the detection device 100 of the embodiment of the present disclosure when performing voltage detection. The first voltage detection unit 102 generates a first detection voltage u1 according to the first voltage u1 output by the object under test RX. c1 The control unit 108 detects the first voltage u c1 The first voltage u1 output by the measured object RX can be determined. Specifically, according to the structure of the first voltage detection unit 102, the control unit 108 determines the first voltage u1 output by the measured object RX. c1 And the voltage division ratio of the first voltage division unit 122 determines the output voltage value of the measured object RX. It should be understood that the output voltage value u1 of the measured object RX conforms to the following formula (4): (4) It is worth noting that the control unit 108 also compares the output voltage value u1 of the measured object RX with the pre-stored predetermined normal voltage value. If the output voltage value u1 of the measured object RX deviates from the predetermined normal voltage value by more than the second predetermined range, the control unit 108 determines that the measured object is abnormal; otherwise, the control unit 108 determines that the measured object is normal. The second predetermined range can be reasonably set according to the specific application scenario. In some embodiments, the second predetermined range is, for example, 10%.

[0047] The detection device 100 also has a self-detection function. Figure 4 1 is a schematic diagram showing a detection device according to an embodiment of the present disclosure when performing a self-test. When performing a self-test, the control unit 108 disconnects the detection interface P1 of the detection device 100 from the object RX to be tested, and controls the first switch K1 to be closed, so that one end of the self-test resistor R6 is connected to the input end of the first voltage detection unit 102. Then, the control unit 108 controls the excitation current source 106 to output the excitation current i in At the same time, the first voltage detection unit 102 detects and outputs a first detection voltage u of the object under test RX. c1 The second voltage detection unit 104 detects and outputs a second detection voltage u about the first resistor R1 c2 .

[0048] The control unit 108 can detect the first voltage u c1 The voltage division ratio of the first voltage division unit 122 determines the self-test voltage U about the self-test resistor R6. R6 The control unit 108 can detect the second voltage u c2 The voltage division ratio of the second voltage division unit 142 determines the self-test voltage U about the first resistor R1. R1 It should be understood that when the detection device 100 is in a normal state, the self-test voltage U of the self-test resistor R6 is R6 The self-test voltage U of the first resistor R1 R1 The following formula (5) is satisfied: (5) Therefore, if the self-test voltage U calculated by the control unit 108 about the first resistor R1 R1 The self-test voltage U of the self-test resistor R6 (R6 represents the resistance value of the self-test resistor R6) R6 The ratio between them conforms to formula (5), that is, the self-test voltage U of the first resistor R1 R1 The self-test voltage U of the self-test resistor R6 R6 If the ratio between them does not deviate from the ratio shown in formula (5) beyond the predetermined range, the control unit 108 determines that the self-test of the detection device 100 is normal. Otherwise, if the self-test voltage U about the first resistor R1 calculated by the control unit 108 isR1 The self-test voltage U of the self-test resistor R6 R6 The ratio between them does not conform to formula (5), that is, the self-test voltage U of the first resistor R1 R1 The self-test voltage U of the self-test resistor R6 R6 If the ratio between them deviates from the ratio shown in formula (5) by more than a predetermined range (for example, the deviation exceeds 20%), the control unit 108 determines that the detection device 100 has a self-test failure. The control unit 108 can generate an alarm signal to prompt the detection device 100 to self-test and find an internal fault. The device power-on self-test function can ensure accurate signal acquisition and precise and reliable signal diagnosis.

[0049] The detection device 100 also has an acquisition mode adaptive function. When performing detection, the control unit 108 first controls the excitation current source 106 to stop outputting the excitation current i in , and receives the first detection voltage u of the measured object RX from the first voltage detection unit 102 c1 If the first detection voltage u of the object RX is c1 If the first detection voltage u of the object RX is greater than the predetermined voltage value, the control unit 108 determines that there is voltage on the object RX under test, and resistance detection cannot be performed at this time. Therefore, the control unit 108 continues to perform voltage detection on the object RX under test. The predetermined voltage value can be reasonably set according to the working voltage of the control system 200 detected by the detection device 100. Otherwise, if the first detection voltage u of the object RX under test is greater than the predetermined voltage value, the control unit 108 determines that there is voltage on the object RX under test, and resistance detection cannot be performed at this time. Therefore, the control unit 108 continues to perform voltage detection on the object RX under test. The predetermined voltage value can be reasonably set according to the working voltage of the control system 200 detected by the detection device 100. c1 If the voltage is not greater than the predetermined voltage value, the control unit 108 determines that there is no voltage on the object RX under test. Therefore, the control unit 108 continues to detect the resistance value of the object RX under test. Through the above means, adaptive selection of the acquisition mode is achieved, and the user is prompted with the channel signal status to avoid damage to the field instrument caused by user misoperation.

[0050] The detection device 100 also has a detection range adaptive function. The control unit 108 can control the excitation current i output by the excitation current source 106 in For example, the excitation current i output by the control excitation current source 106 can be in A plurality of gears are set, and the current of each gear corresponds to a resistance range of a gear, for example. For example, the first gear excitation current corresponds to the first gear resistance range, the second gear excitation current corresponds to the second gear resistance range, the third gear excitation current corresponds to the third gear resistance range, and so on. Among them, the current values ​​of the excitation currents corresponding to the first gear, the second gear, the third gear, etc. decrease in sequence, and correspondingly, the resistance ranges corresponding to the first gear, the second gear, the third gear, etc. increase in sequence. Figure 5A schematic diagram of multiple ranges of the detection device 100 of an embodiment of the present disclosure is shown. Among them, the measurement range corresponding to the first-grade resistance range T1 is the smallest, and the upper limit value of the measurement range is also the smallest. The measurement range corresponding to the second-grade resistance range T2 may include the measurement range corresponding to the first-grade resistance range T1, and the upper limit value of the measurement range of the second-grade resistance range T2 is greater than the upper limit value of the first-grade resistance range T1. The measurement range corresponding to the second-grade resistance range T2 may include the measurement range corresponding to the first-grade resistance range T1 and the second-grade resistance range T2, and the upper limit value of the measurement range of the third-grade resistance range T3 is greater than the upper limit value of the second-grade resistance range T2. It should be understood that the smaller the excitation current, the larger the measurable range corresponding to the detection device 100, but the measurement accuracy of the relatively small resistance value resistor will be reduced. The first-grade excitation current corresponds to the first-grade resistance range, which means that when the excitation current source 106 outputs the excitation current i with the first-grade excitation current, the excitation current i in When the resistance value of the detected target resistor is within the first resistance range, the detection device 100 can obtain the highest accuracy. Otherwise, if the resistance value of the detected target resistor is not within the first resistance range, the result (such as the indication) detected by the detection device 100 will deviate from the first resistance range, and the detection result is not accurate enough and cannot be used as a true detection result.

[0051] When performing resistance detection, the control unit 108 can, for example, control the excitation current source 106 to output an excitation current i at the first gear excitation current. in . And determine the resistance detection value of the measured object RX with respect to the first gear excitation current. The control unit 108 determines whether the obtained resistance detection value is in the first gear resistance range corresponding to the first gear excitation current. If the obtained resistance detection value is in the first gear resistance range corresponding to the first gear excitation current, it means that the first gear resistance range is a suitable resistance range, and the obtained resistance detection value is the true resistance value of the measured object RX.

[0052] If the resistance detection value obtained is not in the first resistance range corresponding to the first excitation current, it means that the first resistance range is not a suitable resistance range, and the resistance detection value obtained is not the true resistance value of the measured object RX. For example, if the resistance detection value obtained is greater than the upper limit of the first resistance range, the control unit 108 adjusts the excitation current i output by the excitation current source 106 according to the resistance detection value obtained. in To a second predetermined current value, the second predetermined current value is a current value smaller than the first gear excitation current, so as to perform resistance detection on the object under test RX again.

[0053] In some embodiments, in order to improve the efficiency of the detection range adaptive operation, the resistance range corresponding to the second predetermined current value can cover the resistance detection value obtained above. For example, if the resistance detection value obtained above is within the range covered by the third resistance range T3 alone, the control unit 108 adjusts the excitation current i output by the excitation current source 106 to in To the third gear excitation current in order to perform resistance detection on the object under test RX again. It should be understood that although the resistance detection value obtained above is within the range covered by the third gear resistance range T3 alone, the resistance detection value obtained above is not the true resistance value of the object under test RX, and there may be deviations. If the resistance detection value obtained again is within the range covered by the third gear resistance range T3 alone, the resistance detection value obtained again is the true resistance value of the object under test RX. If the resistance detection value obtained again is not within the third gear resistance range T3, the control unit 108 adjusts the excitation current i output by the excitation current source 106 according to the resistance detection value obtained again. in To a new current range, repeat the above operation until the real resistance value of the measured object RX is obtained.

[0054] Based on the detection range adaptive function, the range adaptive selection can be realized. For example, the range switching function in the detection device 100 is set with multiple gear resistance thresholds. When the collected channel resistance data exceeds the current range, the switching unit automatically adapts to the appropriate range, and controls the excitation current source to output the corresponding excitation current signal under the range gear, and re-collects the measured resistance under the excitation signal until the measured resistance signal meets the range range. The current source is controlled by the range switching to output the excitation current of different gears to meet the resistance collection requirements of different ranges.

[0055] According to the detection device 100 disclosed in the present invention, a data storage device may be provided inside the detection device 100 to store the collected data. For example, when performing a detection, it is possible to choose whether to store the current data and record the storage time, device type, load type and other parameters to facilitate subsequent data call, viewing and analysis.

[0056] The detection device 100 disclosed in the present invention also has abnormal diagnosis technology and curve analysis functions. Regarding abnormal diagnosis technology, the operator can store the voltage / resistance information about the object under test RX (such as the input and output interface of the control system 200) under normal conditions in the detection device 100 as reference information. Based on the normal working condition reference information, the detection device 100 can realize real-time comparative analysis of the on-site collected signals. When the collected data exceeds the range corresponding to the normal working condition reference information, the detection device 100 determines that the current channel (input and output interface) state is abnormal, and warns the operator of the abnormal information through the display unit, so that the operator can identify on-site fault information without rich on-site experience.

[0057] Regarding the curve analysis function, when users perform curve analysis operations, they can call historical storage data to draw historical curves, and at the same time, they can draw real-time curves for collected data, showing the difference between current working condition data and historical data in an intuitive and efficient manner, helping operators to judge on-site working conditions.

[0058] For example, the control unit 108 generates a fitting curve about the resistance value of the object RX under test according to the historical sampling values ​​of the resistance value of the object RX under test. The control unit 108 can obtain the sampling values ​​at a predetermined frequency and generate a fitting curve about the resistance value of the object RX under test along the time axis based on the sampling values.

[0059] It is worth noting that the detection device 100 disclosed in the present invention also has a fault prediction function. The fault prediction function can preset a fault prediction model and set control system fault model parameters. The intelligent diagnostic device extracts state indicators and sets fault thresholds based on the fault prediction model and historical data, and compares and analyzes the on-site collected signals with the preset fault prediction model to evaluate the health status and remaining working life of the control system. When the control system is close to the fault threshold, an alarm is issued to prompt the user to perform on-site equipment maintenance, thereby realizing control system health status evaluation and fault prediction, and reducing the occurrence of unexpected faults.

[0060] For example, the control unit 108 also predicts the extension curve of the fitting curve in the future according to the change trend presented by the generated fitting curve, that is, predicts the future change of the resistance value of the measured object RX.

[0061] Based on the above-mentioned extended curve formed by predicting the future changes in the resistance value of the measured object RX, the control unit 108 can also predict the decay period of the resistance value of the measured object RX, which is the time it takes for the resistance value of the measured object RX to decay from the rated value to deviate from the rated value by more than a predetermined threshold. For example, when the resistance value of the measured object RX decays to deviate from the rated value by more than a predetermined percentage, it is considered that the measured object RX cannot work normally. At this time, the time point corresponding to the extended curve of the above-mentioned fitting curve is the end point of the service life of the measured object RX. The time from the time when the measured object RX is put into use to the end of the service life is the decay period of the measured object RX.

[0062] It should be understood that based on the above fitting curve and the extended curve, the remaining service life corresponding to the current state of the measured object RX can be determined.

[0063] The detection device 100 disclosed in the present invention is provided with a multiple-choice switch, which can realize fast switching measurement of multiple channels while ensuring the miniaturization of the handheld device. It avoids repeated plugging of cables at the industrial site and improves the test efficiency; at the same time, the detection device 100 can realize the synchronous display of multiple channels based on the human-computer interaction interface. The operator can view the data of each channel separately, or view the data of multiple channels at the same time, compare the data differences between channels, and conduct a comprehensive diagnosis of the on-site working conditions.

[0064] On-site fault diagnosis of the control system is achieved through the detection device 100, and intelligent detection equipment is incorporated into the wiring terminals of the control system and the instrument. The control system channel resistance / voltage signal acquisition is achieved through the built-in signal acquisition unit, and the channel acquisition data and diagnostic information are displayed through the display unit. The on-site power-on status of the control system is determined through the mode switching unit to achieve adaptive selection of the voltage / resistance acquisition mode. The range switching unit is used to achieve equipment range adaptation to meet different range measurement requirements. The data diagnosis and analysis unit and the fault prediction unit are used to achieve control system fault diagnosis and prediction.

[0065] It is worth mentioning that the fault diagnosis function of the detection device 100 is that the detection device 100 can collect the control system voltage information when the control system is powered on, and collect the control system resistance when the control system is powered off, thereby realizing the control system voltage and resistance information collection and diagnosis.

[0066] On the other hand, the resistance acquisition of the detection device 100 is carried out through external excitation. For example, the detection device 100 controls the excitation current source 106 to generate an excitation current, thereby acquiring channel resistance information and realizing resistance signal acquisition when the control system is powered off. The design is simple and the operation is convenient.

[0067] Furthermore, the detection device 100 has acquisition mode adaptive technology and acquisition range adaptive technology. It detects the power-on status of the control system through pre-acquisition technology, automatically selects the voltage / resistance acquisition mode, and prompts the user of the channel signal status to avoid damage to the on-site equipment caused by user misoperation; at the same time, according to the value of the acquired signal, the excitation current size is changed, and the equipment detection range is automatically adjusted to meet the measurement of resistance signals in different ranges, thereby improving detection efficiency.

[0068] At the same time, the detection device 100 has a power-on self-detection function. Through the power-on self-detection method of the device, it ensures that the signal acquisition circuit works normally and ensures that the signal diagnosis is accurate and reliable. If the detection finds that there is an abnormality in the device acquisition circuit, the user is warned through the display unit.

[0069] In addition, the detection equipment 100 has intelligent data diagnosis and analysis technology, which can diagnose the field signal status of the current control system based on the channel reference information under normal working conditions, and alert the user of abnormal information through the display unit. The operator can also identify field fault information without rich field experience; at the same time, real-time curves can be drawn for the stored historical data and collected data to intuitively display the field working condition signal status.

[0070] In addition, the detection device 100 can realize a fault prediction function, which can preset a fault prediction model, set a system fault threshold, and evaluate the health status and remaining working life of the control system based on comparative analysis of field collected signals and preset fault prediction models to realize fault prediction.

[0071] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

[0072] The above are only optional embodiments of the present disclosure and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A detection device for a control system, It is characterized in that include: A first voltage detection unit, wherein an input terminal of the first voltage detection unit is electrically connected to a measured object related to the control system, and the first voltage detection unit is configured to output a first detection voltage; An excitation current source, wherein a current output terminal of the excitation current source is electrically connected to one end of the first resistor and an input terminal of the second voltage detection unit; a second voltage detection unit, the second voltage detection unit being configured to output a second detection voltage; a first resistor, wherein the other end of the first resistor is electrically connected to the input end of the first voltage detection unit; as well as A control unit is configured to control the excitation current source to output an excitation current so as to determine a resistance detection value of the object under test based on the first detection voltage, the second detection voltage and the first resistance, and to determine that the object under test is abnormal in response to determining that the resistance detection value of the object under test deviates from a predetermined normal resistance value by more than a first predetermined range.

2. The detection device according to claim 1, It is characterized in that The control unit is further configured to control the excitation current source to stop outputting the excitation current, so as to determine the output voltage value of the measured object based on at least the first detection voltage, and to determine that the measured object is abnormal in response to determining that the output voltage value of the measured object deviates from a predetermined normal voltage value beyond a second predetermined range; The objects under test include the input and output interfaces of the control system.

3. The detection device according to claim 2, It is characterized in that The first voltage detection unit includes: a first voltage follower, wherein an input terminal of the first voltage follower is configured as an input terminal of the first voltage detection unit; and A first voltage dividing unit, wherein an input end of the first voltage dividing unit is electrically connected to an output end of the first voltage follower, and an output end of the first voltage dividing unit is used to output a first detection voltage; The control unit is further configured to determine an output voltage value of the measured object based at least on the first detection voltage and a voltage division ratio of the first voltage division unit.

4. The detection device according to claim 1, It is characterized in that The control unit is configured to: control the excitation current source to output an excitation current having a first predetermined current value so as to determine a resistance detection value of the object under test relative to the first predetermined current value, wherein the first predetermined current value corresponds to a first resistance range, and in response to determining that the resistance detection value is greater than an upper limit of the first resistance range, control the excitation current source to output an excitation current having a second predetermined current value, wherein the second predetermined current value is less than the first predetermined current value.

5. The detection device according to claim 4, It is characterized in that The resistance detection value is within a second resistance range corresponding to the second predetermined current value.

6. The detection device according to claim 2, It is characterized in that The control unit is further configured to: in response to determining that the output voltage value of the measured object is less than a predetermined voltage threshold, control the excitation current source to output an excitation current so as to determine the resistance detection value of the measured object.

7. The detection device according to claim 1, It is characterized in that Also includes: A self-test resistor, one end of which is electrically connected to one end of the first switch; as well as a first switch, the other end of the first switch being electrically connected to the other end of the first resistor; The control unit is also configured to: disconnect the detection device from the object under test, close the first switch, and control the excitation current source to output an excitation current, so as to determine whether the detection device has an internal fault based on the first detection voltage, the second detection voltage and the first resistance.

8. The detection device according to claim 1, It is characterized in that The control unit is further configured to generate a fitting curve about the resistance detection value of the object to be measured according to the historical sampling values ​​of the resistance detection value of the object to be measured.

9. The detection device according to claim 8, It is characterized in that The control unit is further configured to predict a decay period of the resistance detection value of the measured object according to the fitting curve, wherein the decay period is the time taken for the resistance detection value of the measured object to decay from a rated value to deviate from the rated value by more than a predetermined threshold.

10. The detection device according to claim 3, It is characterized in that The second voltage detection unit includes: a second voltage follower, wherein an input terminal of the second voltage follower is configured as an input terminal of the second voltage detection unit; and A second voltage dividing unit, wherein an input end of the second voltage dividing unit is electrically connected to an output end of the second voltage follower, and an output end of the second voltage dividing unit is used to output a second detection voltage; The control unit is further configured to determine a resistance detection value of the object under test according to the first detection voltage, the voltage division ratio of the first voltage division unit, the second detection voltage, the voltage division ratio of the second voltage division unit, and the first resistance.

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