Multiplexing signal on-line detection circuit

Abstract

The utility model relates to the technical field of signal detection, in particular to a multiplexing signal online detection circuit, which comprises an industrial control computer (IPC), a multifunctional digital multimeter (DMM), a logic control circuit, a matrix relay driving circuit and a multi-path double-pole single-throw solid-state relay, the IPC communicates with the DMM through a data bus to configure a detection function and obtain detection data, is connected with the logic control circuit through a three-bit digital output port, controls the on-off of the corresponding double-pole single-throw solid-state relay through the matrix relay driving circuit, realizes automatic switching of a detection channel, and cooperates with the DMM to complete online detection of a detected signal. According to the utility model, the detection circuit is simplified, automatic continuous detection of multiple types of signals can be realized without manual operation, the problems that multiple special instruments are needed, manual operation is tedious and automatic online detection cannot be realized in the existing multi-type electric signal detection are solved, and the detection efficiency and the automation degree are improved.

Description

Technical Field

[0001] This utility model relates to the field of signal detection technology, and in particular to an online detection circuit for multiplexed signals. Background Technology

[0002] Currently, in the field of laser measurement, to further improve detection accuracy, it is necessary to compensate for errors in environmental, geometric, optical, signal, and system aspects of the process. Environmental error compensation, in particular, involves factors such as temperature, humidity, and vibration. Since the output signal types of various environmental sensors differ, corresponding general-purpose measuring instruments are used to detect electrical parameters for different signal types. Detection methods often employ voltmeters, ammeters, multimeters, electronic thermometers, etc., to measure and record the signals to be detected. This approach involves numerous standard instruments, complex detection circuits, cumbersome manual operation, and low automation.

[0003] To enable parameter detection of various electrical signals, a multi-function digital multimeter (DMM) can be used to replace various general-purpose instruments used in conventional testing processes, such as DC voltmeters, ammeters, AC voltmeters, ammeters, electronic thermometers, and RCL testers. However, manual operation is still required during the testing process. The DMM's measurement functions must be continuously set according to different measurement needs, and manual operation of the corresponding measurement ports is necessary to achieve the detection and recording of different electrical parameters. The testing process is complex and cannot achieve online detection of AC and DC current signals, resulting in low work efficiency.

[0004] Therefore, this invention proposes an online detection circuit for multiplexed signals to solve the above problems. Utility Model Content

[0005] This invention addresses the shortcomings of existing technologies by proposing an online detection circuit for multiplexed signals. This invention enables online automatic detection, data recording, and storage of electrical parameters from various AC voltages, currents, frequencies, DC voltages, currents, as well as temperature, humidity, and vibration sensors in the circuit under test.

[0006] The technical solution of this utility model to solve the technical problem is an online detection circuit for multiplexed signals, including an industrial control computer (IPC) and a multi-function digital multimeter (DMM). The communication port of the IPC and the communication port of the DMM are connected through a data bus. It also includes a logic control circuit, a matrix relay drive circuit, and a multi-channel double-pole single-throw solid-state relay.

[0007] The IPC is equipped with a three-digit digital output port DO, and the three output terminals of the three-digit digital output port DO are connected to the input terminals of the logic control circuit.

[0008] The output of the logic control circuit is connected to the input of the matrix relay drive circuit;

[0009] The output of the matrix relay drive circuit is connected one-to-one with the control coil of each double-pole single-throw solid-state relay.

[0010] The two moving contacts of each double-pole single-throw solid-state relay are connected to the corresponding input terminal of the measured signal, and the common terminal of the two stationary contacts of each double-pole single-throw solid-state relay is connected to the red probe measurement terminal and the black probe measurement terminal of the DMM, respectively.

[0011] The logic control circuit includes a decoder chip U1, which is a 74LS138 decoder chip.

[0012] The three output terminals of the IPC's three-digit digital output port DO are connected one-to-one with the address input port A, address input port B, and address output port C of the 74LS138 chip.

[0013] The enable pin G1 of the 74LS138 chip is connected to a 15V positive power supply. The enable pins G2AN and G2BN are both grounded to GND. The 74LS138 chip's 7 output pins 15-9 are connected one-to-one with the 7 input pins 1-7 of the matrix relay drive circuit.

[0014] Pin 15 of the 74LS138 chip is the 0th decoder output, which is connected to pin 1 in the matrix relay drive circuit;

[0015] Pin 13 of the 74LS138 chip is the first decoder output, which is connected to pin 2 in the matrix relay drive circuit;

[0016] Pin 13 of the 74LS138 chip is the second decoder output, which is connected to pin 3 in the matrix relay drive circuit;

[0017] Pin 12 of the 74LS138 chip is the third decoder output, which is connected to pin 4 in the matrix relay drive circuit;

[0018] Pin 11 of the 74LS138 chip is the fourth decoder output, which is connected to pin 5 in the matrix relay drive circuit;

[0019] Pin 10 of the 74LS138 chip is the 5th decoder output, which is connected to pin 6 in the matrix relay driver circuit;

[0020] Pin 9 of the 74LS138 chip is the 6th decoder output, which is connected to pin 7 in the matrix relay driver circuit.

[0021] The matrix relay drive circuit includes a Darlington transistor array U2, which uses a chip of model ULN2004A.

[0022] Pin 9 of the ULN2004A chip is connected to a 15V positive power supply, and the ground pin is grounded.

[0023] The 7 output pins 16-10 of the ULN2004A chip are connected to one end of the control coil of the corresponding number of double-pole single-throw solid-state relays. The other end of the control coil of all double-pole single-throw solid-state relays is connected to a 15V positive power supply.

[0024] The dual-pole single-throw solid-state relays are configured with a total of 7 channels, namely relay K1, relay K2, relay K3, relay K4, relay K5, relay K6, and relay K7.

[0025] The two sets of moving contacts of relay K1 are respectively connected to the two ends of the +28V DC device under test;

[0026] The two sets of moving contacts of relay K2 are respectively connected to the two ends of the sampling resistor Rs in the DC test device RL circuit;

[0027] The two sets of moving contacts of relay K3 are respectively connected to the two ends of the 115V AC tested device;

[0028] The two sets of moving contacts of relay K4 are respectively connected to the two ends of the sampling resistor Rs in the AC test circuit;

[0029] The two sets of moving contacts of relay K5 are connected to the two ends of the AC signal source respectively;

[0030] The two sets of moving contacts of relay K6 are connected to the two ends of the thermocouple respectively;

[0031] The two sets of moving contacts of relay K7 are connected to the frequency signal detection terminal accordingly;

[0032] The common terminal of the first set of stationary contacts of relays K1 to K7 is connected to the red probe of the DMM, and the common terminal of the second set of stationary contacts is connected to the black probe of the DMM.

[0033] The effects provided in the utility model description are merely those of the embodiments, and not all the effects of the utility model. The above technical solution has the following advantages or beneficial effects:

[0034] This utility model discloses an online detection circuit for multiplexed signals. This circuit achieves automatic selection of 7 detection channels through a 3-bit digital I / O port, significantly simplifying IPC I / O usage. It features a simple hardware structure, low cost, and high reliability. The circuit integrates detection capabilities for various common industrial parameters such as DC voltage / current, AC voltage / current, frequency, and temperature, offering strong versatility and adaptability to online detection needs in multiple scenarios. A double-pole single-throw relay is used to isolate the measured signal from the measurement end. Combined with the interlocking characteristics of the decoder, only one channel conducts at a time, effectively avoiding crosstalk between multiple signals and ensuring measurement accuracy. Furthermore, based on an IPC and DMM architecture, it achieves fully automatic online detection of multiple signals without the need for manual probe switching, significantly improving detection efficiency and reducing human error. Attached Figure Description

[0035] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0036] Figure 1 This is a schematic diagram of the method flow of this utility model.

[0037] Figure 2 This is a flowchart illustrating the working principle of this utility model. Detailed Implementation

[0038] To clearly illustrate the technical features of this solution, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings. The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below.

[0039] like Figure 1 As shown, an online detection circuit for multiplexed signals includes an industrial control computer (IPC) and a multi-function digital multimeter (DMM). The communication ports of the IPC and the DMM are connected via a data bus. The circuit also includes a logic control circuit, a matrix relay drive circuit, and a multi-channel double-pole single-throw solid-state relay.

[0040] The IPC communicates with the DMM via a data bus to issue inspection item setting instructions to the DMM and to acquire inspection data collected by the DMM.

[0041] The IPC's three-digit digital output port DO is connected to the input terminal of the logic control circuit, and the output terminal of the logic control circuit is connected to the input terminal of the matrix relay drive circuit.

[0042] The output of the matrix relay drive circuit is connected to multiple double-pole single-throw solid-state relays. The two ends of the contacts of each double-pole single-throw solid-state relay are connected to the corresponding measured signal terminal. The common terminal of all double-pole single-throw solid-state relays is connected to the two measurement terminals of the DMM. The two measurement terminals of the DMM are the red probe and the black probe, respectively.

[0043] The IPC outputs a strobe code to the logic control circuit via a three-digit digital output port DO. After decoding by the logic control circuit, a control signal is output to the matrix relay drive circuit, which drives the corresponding number of double-pole single-throw solid-state relays to switch states. In conjunction with the corresponding detection function of the DMM, online detection of the corresponding measured signal is realized.

[0044] In a specific implementation, the logic control circuit is as follows:

[0045] The logic control circuit includes a decoder chip U1, which uses a 74LS138 chip.

[0046] The three digital output ports DO of the IPC are connected to the address input ports A, B, and C of the 74LS138 chip, respectively. The enable pin 6 of the 74LS138 chip is connected to a 15V positive power supply, and the enable pins 4 and 5 are grounded to GND. The seven output terminals of the 74LS138 chip (pins 15, 14, 13, 12, 11, 10, and 9 are pronounced as Y0, Y1, Y2, Y3, Y4, Y5, and Y6, respectively) are connected to the input terminals of the matrix relay drive circuit (pins 1-7 of the ULN2004A).

[0047] Among them, decoder U1 adopts 74LS1383 line-to-8 line decoder, using only 7 outputs (Y0-Y6) to realize 3-bit DO port control of 7 channels. It has natural interlocking characteristics, and only 1 output is effective at the same time, which can avoid signal crosstalk and short circuit risks caused by multiple channels being turned on at the same time.

[0048] In a specific implementation, the matrix relay driving circuit is as follows:

[0049] The matrix relay drive circuit includes a Darlington transistor array U2, which uses the ULN2004A chip.

[0050] The 7 input pins 1-7 of the ULN2004A chip are connected to the 7 output pins 15-9 of the 74LS138 chip respectively. Pin 9 of the ULN2004A chip is connected to a 15V positive power supply, and pin 8 is grounded (GND). The 7 output pins 16-10 of the ULN2004A chip are connected to one end of the control coil of the corresponding number of double-pole single-throw solid-state relays K1 to K7. The other end of the control coil of all double-pole single-throw solid-state relays is connected to a 15V positive power supply.

[0051] Among them, the driver chip U2 adopts the ULN2004A Darlington transistor array, with a maximum single-channel drive current of 500mA, which can directly drive the solid-state relay control coil without the need for additional external circuits, thus simplifying the hardware design.

[0052] In a specific implementation, the double-pole single-throw solid-state relay is as follows:

[0053] The dual-pole single-throw solid-state relays are configured with a total of 7 channels, namely relays K1, K2, K3, K4, K5, K6, and K7;

[0054] The two sets of moving contacts of relay K1 are respectively connected to the two ends of the +28V DC device under test, and are used to cooperate with the DC voltage detection function of DMM to perform DC voltage detection;

[0055] The two sets of moving contacts of relay K2 are respectively connected to the two ends of the sampling resistor Rs in the DC test device RL circuit, in order to cooperate with the DC current detection function of DMM to realize DC current detection;

[0056] The two sets of moving contacts of relay K3 are respectively connected to the two ends of the 115V AC device under test, and are used to cooperate with the AC voltage detection function of DMM to perform AC voltage detection.

[0057] The two sets of moving contacts of relay K4 are respectively connected to the two ends of the sampling resistor Rs in the AC test circuit, and are used to cooperate with the AC current detection function of DMM to perform AC current detection.

[0058] The two sets of moving contacts of relay K5 are connected to the two ends of the AC signal source to cooperate with the corresponding detection function of DMM to detect extended electrical parameters.

[0059] The two sets of moving contacts of relay K6 are connected to the two ends of the thermocouple respectively, and are used to cooperate with the temperature detection function of DMM for temperature detection;

[0060] The two sets of moving contacts of relay K7 are connected to the frequency signal detection terminal to cooperate with the frequency detection function of DMM and the frequency detection of AC signals.

[0061] In a specific implementation, the sampling resistor Rs is any one of the following: M-type manganese copper wire sampling resistor, U-type manganese copper wire sampling resistor, or precision functional sampling resistor. It has low temperature drift and high accuracy, which can ensure the accuracy of AC and DC current sampling.

[0062] The relay uses an industrial-grade double-pole single-throw solid-state relay (SSR), which has no mechanical contact wear, long life, fast response speed, and is suitable for high-frequency automatic switching scenarios. The contact on-resistance is low and does not affect the measurement accuracy of mV-level thermocouple signals.

[0063] In the specific implementation, the output voltage of the DC device under test RL is +28V;

[0064] The output voltage of the AC device under test is 115V.

[0065] In specific implementation methods, such as Figure 2 As shown, the working principle of the circuit in this utility model is as follows:

[0066] S1. The industrial control computer (IPC) pre-stores the measurement function parameters and detection channel mapping relationship corresponding to each measured signal. The detection channel is equipped with a double-pole single-throw solid-state relay controlled by the IPC through a logic control circuit and a matrix relay drive circuit. The common terminal of each double-pole single-throw solid-state relay is connected to the two measurement terminals of the DMM. The contact terminal of each double-pole single-throw solid-state relay is connected to the corresponding measured signal terminal one by one.

[0067] S2 and IPC determine the target signal to be detected based on the preset detection task, and retrieve the target measurement function parameters and target detection channel corresponding to the target signal.

[0068] S3 and IPC send configuration commands to DMM via the data bus to configure the DMM's measurement mode to match the target measurement function parameters of the target measured signal;

[0069] S4 and IPC output the gating code corresponding to the target detection channel to the logic control circuit through the three-digit digital output port DO. After being decoded by the logic control circuit, the corresponding control signal is output to the matrix relay drive circuit. The matrix relay drive circuit drives the double-pole single-throw solid-state relay corresponding to the target detection channel to conduct, so that the target measured signal end and the DMM measurement end form a conduction detection loop.

[0070] S5 and IPC trigger DMM to perform detection operations, acquire the detection data of the target signal collected by DMM through the data bus and complete the storage;

[0071] S6 and IPC execute S2 to S5 in a loop according to the preset detection task sequence, and complete the automatic online detection of all the signals under test in sequence.

[0072] The state switching of relay contact terminals for various function detections and the setting of DMM measurement functions are controlled by the IPC control program, which completes the function setting, data communication and signal acquisition with the DMM through the data bus; at the same time, the logic control of acquisition channel selection and relay drive switching are realized by selecting the output of the DO port, thereby realizing the online detection and multiplexing function of various signals.

[0073] Although the specific embodiments of the utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the utility model. Based on the technical solution of the utility model, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the utility model.

Claims

1. An online detection circuit for multiplexed signals, comprising an industrial control computer (IPC) and a multi-function digital multimeter (DMM), wherein the communication port of the IPC and the communication port of the DMM are connected via a data bus, characterized in that, It also includes logic control circuits, matrix relay drive circuits, and multi-channel double-pole single-throw solid-state relays; The IPC is equipped with a three-digit digital output port DO, and the three output terminals of the three-digit digital output port DO are connected to the input terminals of the logic control circuit. The output of the logic control circuit is connected to the input of the matrix relay drive circuit; The output of the matrix relay drive circuit is connected one-to-one with the control coil of each double-pole single-throw solid-state relay. The two moving contacts of each double-pole single-throw solid-state relay are connected to the corresponding input terminal of the measured signal, and the common terminal of the two stationary contacts of each double-pole single-throw solid-state relay is connected to the red probe measurement terminal and the black probe measurement terminal of the DMM, respectively.

2. The online detection circuit for multiplexed signals according to claim 1, characterized in that, The logic control circuit includes a decoder chip U1, which is a 74LS138 decoder chip. The three output terminals of the IPC's three-digit digital output port DO are connected one-to-one with the address input port A, address input port B, and address output port C of the 74LS138 chip. The enable pin G1 of the 74LS138 chip is connected to a 15V positive power supply. The enable pins G2AN and G2BN are both grounded to GND. The 74LS138 chip's 7 output pins 15-9 are connected one-to-one with the 7 input pins 1-7 of the matrix relay drive circuit.

3. The online detection circuit for multiplexed signals according to claim 2, characterized in that: Pin 15 of the 74LS138 chip is the 0th decoder output, which is connected to pin 1 in the matrix relay drive circuit; Pin 13 of the 74LS138 chip is the first decoder output, which is connected to pin 2 in the matrix relay drive circuit; Pin 13 of the 74LS138 chip is the second decoder output, which is connected to pin 3 in the matrix relay drive circuit; Pin 12 of the 74LS138 chip is the third decoder output, which is connected to pin 4 in the matrix relay drive circuit; Pin 11 of the 74LS138 chip is the fourth decoder output, which is connected to pin 5 in the matrix relay drive circuit; Pin 10 of the 74LS138 chip is the 5th decoder output, which is connected to pin 6 in the matrix relay driver circuit; Pin 9 of the 74LS138 chip is the 6th decoder output, which is connected to pin 7 in the matrix relay driver circuit.

4. The online detection circuit for multiplexed signals according to claim 1, characterized in that, The matrix relay drive circuit includes a Darlington transistor array U2, which uses a chip of model ULN2004A. Pin 9 of the ULN2004A chip is connected to a 15V positive power supply, and the ground pin is grounded. The 7 output pins 16-10 of the ULN2004A chip are connected to one end of the control coil of the corresponding number of double-pole single-throw solid-state relays. The other end of the control coil of all double-pole single-throw solid-state relays is connected to a 15V positive power supply.

5. The online detection circuit for multiplexed signals according to claim 1, characterized in that, The double-pole single-throw solid-state relay has a total of 7 channels, namely relay K1, relay K2, relay K3, relay K4, relay K5, relay K6 and relay K7.

6. The online detection circuit for multiplexed signals according to claim 5, characterized in that: The two sets of moving contacts of relay K1 are respectively connected to the two ends of the +28V DC device under test; The two sets of moving contacts of relay K2 are respectively connected to the two ends of the sampling resistor Rs in the DC test device RL circuit; The two sets of moving contacts of relay K3 are respectively connected to the two ends of the 115V AC tested device; The two sets of moving contacts of relay K4 are respectively connected to the two ends of the sampling resistor Rs in the AC test circuit; The two sets of moving contacts of relay K5 are connected to the two ends of the AC signal source respectively; The two sets of moving contacts of relay K6 are connected to the two ends of the thermocouple respectively; The two sets of moving contacts of relay K7 are connected to the frequency signal detection terminal accordingly; The common terminal of the first set of stationary contacts of relays K1 to K7 is connected to the red probe of the DMM, and the common terminal of the second set of stationary contacts is connected to the black probe of the DMM.

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