A highly reliable multi-type power front-end temperature acquisition device and system

Abstract

The present invention relates to a highly reliable multi-type power front-end temperature acquisition device and system, wherein the device includes: a power supply and a system side circuit and a field side circuit connected to the power supply, the power supply supplies power to the system side circuit and the field side circuit after transformation and isolation, and the system side circuit and the field side circuit are connected in communication; the field side circuit is used to control the conduction of the signal acquisition channel corresponding to each detection signal according to the signal detection information, and pre-process the detection signal, and then send the pre-processed detection signal and the precision resistance signal provided inside the field side circuit to the system side circuit; the system side circuit is used to compare and process the processed detection signal with the precision resistance signal to obtain the field temperature value to be measured. The present invention can realize the configuration of multiple types of signals such as millivolt signal, resistance signal, thermocouple, and thermal resistor, and has good anti-interference characteristics.

Description

Technical Field

[0001] The present invention relates to the field of automation and instrumentation technology, and in particular to a high-reliability multi-type power front-end temperature acquisition device and system. Background Art

[0002] In the field of industrial control, the power front-end signal acquisition device is an important module for the input signal of the field control station. The type of signals that can be collected and the reliability of the device are very important. Domestic medium and large thermal power plants usually use centralized control systems, but the field signals are relatively scattered. In practical applications, there are often too many temperature simulation signal acquisition points, which is very costly.

[0003] Signal acquisition devices are often used to collect signals from temperature sensors at production sites and public works. Currently, analog signal input devices can only collect a single type of signal, which cannot meet complex temperature measurement requirements. In addition, the environmental interference at the temperature measurement site is usually large, so the device must have good anti-interference performance. The system needs to use a simpler channel signal type configuration method to meet maintenance and detection requirements. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a highly reliable multi-type power front-end temperature acquisition device and system, which solves the technical problems that the signal types collected by the existing signal acquisition devices are relatively single, cannot meet more complex temperature measurement requirements and do not have good anti-interference functions.

[0006] (II) Technical solution

[0007] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0008] On the one hand, an embodiment of the present invention provides a highly reliable multi-type power front-end temperature acquisition device, comprising: a power supply and a system-side circuit and a field-side circuit connected to the power supply, the power supply supplies power to the system-side circuit and the field-side circuit after transformation and isolation, and the system-side circuit and the field-side circuit are communicatively connected;

[0009] The field side circuit is used to control the conduction of the signal acquisition channel corresponding to each detection signal according to the signal detection information, and pre-process the detection signal, and then send the pre-processed detection signal and the precision resistance signal provided inside the field side circuit to the system side circuit;

[0010] The system side circuit is used to compare and process the processed detection signal with the precision resistance signal to obtain the on-site temperature value to be measured.

[0011] Optionally, the field side circuit includes: a multi-channel signal acquisition and conditioning circuit and a precision resistance control circuit and a magnetic isolation circuit connected to the multi-channel signal acquisition and conditioning circuit, and the precision resistance control circuit and the magnetic isolation circuit are also connected to the system side circuit;

[0012] The precision control circuit is used to provide precision resistance information;

[0013] The magnetic isolation circuit is used to perform magnetic isolation on the signal input into the system side circuit;

[0014] The multi-channel signal acquisition and conditioning circuit is used to control the signal acquisition channels corresponding to each detection signal to be turned on when several types of signal inputs are detected, and to filter and A / D convert the detection signal, and then send the processed detection signal and the precision resistance signal obtained from the precision resistance control circuit to the system side circuit through the magnetic isolation circuit.

[0015] Optionally, the multi-channel signal acquisition and conditioning circuit includes: a port strong current misconnection prevention circuit, a signal acquisition channel, a channel control switch and an AD sampling circuit;

[0016] The port strong current misconnection protection circuit is arranged at the signal input end of each signal acquisition channel, and is used for overvoltage and overcurrent protection of each signal acquisition channel;

[0017] The channel control switch is used to control each of the signal acquisition channels to be turned on or off;

[0018] The AD sampling circuit is used to perform analog-to-digital conversion and digital filtering on the temperature detection signals received by each of the signal acquisition channels.

[0019] Optionally, the port anti-misconnection circuit of strong electricity includes: a bypass capacitor, a fuse and a TVS tube; one end of the bypass capacitor and one end of the fuse are both connected to the signal input end of the signal acquisition channel, the other end of the fuse is connected to one end of the TVS tube, and the other end of the bypass capacitor and the other end of the TVS tube are both grounded.

[0020] Optionally, the field measurement circuit is further provided with a compensation circuit connected to the multi-channel signal acquisition and conditioning circuit and the system side circuit respectively;

[0021] The compensation circuit is a TC voltage bias circuit for cold-end temperature compensation;

[0022] When the temperature detection signal is detected by the thermocouple, the TC voltage bias circuit is started by the DIP switch to perform cold end temperature compensation.

[0023] Optionally, the field-side circuit further comprises: an RS485 communication module connected to the power supply and the system-side circuit respectively;

[0024] The RS485 communication module includes: a communication interface connected to a preset external device, a signal isolation circuit connected to the system side circuit, and a power isolation module connected to the power supply;

[0025] The communication interface is used to receive control information of a preset external device and send it to the system side circuit through the power isolation module.

[0026] Optionally, the system side circuit includes: a main controller and an IPS communication interface, an RS485 communication interface, a latch circuit and a watchdog circuit connected to the main controller;

[0027] The IPS communication interface is used for information transmission between the main controller and the compensation circuit, the precision resistance control circuit and the magnetic isolation circuit;

[0028] The RS485 communication interface is used for information transmission between the main controller and the signal isolation circuit;

[0029] The latch circuit is used to obtain the state of the DIP switch and / or control the lighting of the indicator light according to the control information output by the controller;

[0030] The main controller is used to output control information to the latch circuit, and is also used to control the AD sampling circuit to collect the output signal of the compensation circuit through the IPS communication interface after obtaining the state of the dial switch.

[0031] Optionally, the system side circuit further includes: an expansion and interaction circuit connected to the main controller, and the expansion and interaction circuit includes: a JTAG interface module and an LCD interface module.

[0032] Optionally,

[0033] The power front-end temperature acquisition device has 24 signal acquisition channels;

[0034] The detection signals include: 0-20mV voltage signal, 0-100mV voltage signal, thermocouple signal, two / three-wire PT100, Cu50, PT1000 thermal resistance signal and resistance signal; the thermocouple signals include: E, J, K, N, T, B, S, R.

[0035] On the other hand, an embodiment of the present invention further provides a highly reliable multi-type power front-end temperature acquisition system, comprising: the power front-end temperature acquisition device as described above, and a host computer and / or a switching interface communicatively connected to the power front-end temperature acquisition device;

[0036] The host computer and / or the switching interface is used to output configuration information of the sampling signal type for each signal acquisition channel to the power front-end temperature acquisition device, so that the power front-end temperature acquisition device determines the measurement signal type supported by each signal acquisition channel according to the configuration information.

[0037] (III) Beneficial effects

[0038] The beneficial effects of the present invention are as follows: in view of the increasingly complex application scenarios and temperature measurement requirements, the power front-end temperature acquisition device disclosed in the present invention supports the simultaneous measurement of multi-channel and multi-type signals, and adopts comprehensive protection measures combining multiple isolation circuits with anti-interference measures to ensure the stable sampling and highly reliable operation of the temperature acquisition device. Therefore, the temperature acquisition device of the present invention has strong anti-interference characteristics for some easily triggered events such as power grid interference, EMC, and strong power misconnection, and the channel signal type configuration process of the temperature acquisition device is not complicated, which has great time and cost advantages in daily maintenance and overhaul. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the structure of a highly reliable multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of a circuit structure for protecting against misconnection of strong electricity of a highly reliable multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of the internal structure of a PHOTOMOS tube of a highly reliable multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of the structure of an optocoupler isolation device for a high-reliability multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention;

[0043] Figure 5 A schematic diagram of the internal structure of a magnetic isolation chip of a high-reliability multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention;

[0044] Figure 6 A schematic diagram of the circuit structure of a compensation circuit of a high-reliability multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention;

[0045] Figure 7 A schematic diagram of the circuit structure of a multi-channel signal acquisition and conditioning circuit and a precision resistance control circuit of a high-reliability multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention;

[0046] Figure 8 A schematic diagram of the circuit structure of a latch circuit of a high-reliability multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention;

[0047] Fig. 9 A schematic diagram of the circuit structure of an expansion and interaction circuit of a high-reliability multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0049] like Figure 1 As shown, a high-reliability multi-type power front-end temperature acquisition device proposed in an embodiment of the present invention includes: a power supply and a system-side circuit and a field-side circuit connected to the power supply, the power supply supplies power to the system-side circuit and the field-side circuit after transformation and isolation, and the system-side circuit and the field-side circuit are communicatively connected; the field-side circuit is used to control the conduction of the signal acquisition channel corresponding to each detection signal according to the signal detection information, and pre-process the detection signal, and then send the pre-processed detection signal and the precision resistance signal provided inside the field-side circuit to the system-side circuit; the system-side circuit is used to compare and process the processed detection signal with the precision resistance signal to obtain the field temperature value to be measured.

[0050] In view of the increasingly complex application scenarios and temperature measurement requirements, the power front-end temperature acquisition device disclosed in the present invention supports the simultaneous measurement of multi-channel and multi-type signals, and adopts comprehensive protection measures combining multiple isolation circuits with anti-interference measures to ensure the stable sampling and high-reliability operation of the temperature acquisition device. Therefore, the temperature acquisition device of the present invention has strong anti-interference characteristics for some easily triggered events such as power grid interference, EMC, and strong power misconnection, and the channel signal type configuration process of the temperature acquisition device is not complicated, which has great time and cost advantages in daily maintenance and repair.

[0051] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0052] like Figure 1As shown, the field side circuit includes: a multi-channel signal acquisition and conditioning circuit and a precision resistance control circuit and a magnetic isolation circuit connected to the multi-channel signal acquisition and conditioning circuit, and the precision resistance control circuit and the magnetic isolation circuit are also connected to the system side circuit; the precision control circuit is used to provide precision resistance information; the magnetic isolation circuit is used to magnetically isolate the signal input to the system side circuit; the multi-channel signal acquisition and conditioning circuit is used to control the signal acquisition channel corresponding to each detection signal to be turned on when several types of signal inputs are detected, and to filter and A / D convert the detection signal, and then send the processed detection signal and the precision resistance signal obtained from the precision resistance control circuit to the system side circuit through the magnetic isolation circuit.

[0053] Furthermore, the multi-channel signal acquisition and conditioning circuit includes: a port anti-strong current misconnection circuit, a signal acquisition channel, a channel control switch, and an AD sampling circuit; the port anti-strong current misconnection circuit is arranged at the signal input end of each signal acquisition channel, and is used to protect each signal acquisition channel from overvoltage and overcurrent; the channel control switch is used to control each signal acquisition channel to be turned on or off; the AD sampling circuit is used to perform analog-to-digital conversion and digital filtering on the temperature detection signal received by each signal acquisition channel. Specifically, Figure 7 As shown, the signal acquisition channel includes switches U1...U2N (model TLP181GB). The switch control signals SEL1...SELN, when one of the control signals is at a low level, the channel is selected. Among them, the precision resistor control circuit includes U3, U4 (model TLP181GB) and a precision resistor. When SELP is at a low level, the precision resistor control circuit measures the resistance value of the precision resistor.

[0054] Furthermore, if Figure 2 As shown, the port protection circuit against misconnection of strong electricity includes: bypass capacitor, fuse and TVS tube; one end of the bypass capacitor and one end of the fuse are connected to the signal input end of the signal acquisition channel; the other end of the fuse is connected to one end of the TVS tube, and the other end of the bypass capacitor and the other end of the TVS tube are grounded. After the field signal is connected to the power front-end temperature acquisition device, a capacitor is connected across the input ends, and then the bypass capacitor is connected in parallel to filter out clutter; a self-recovery fuse is connected in series. When the input signal current is greater than the fuse melting current, the fuse is disconnected to prevent large current from entering the device; then a TVS tube is connected in parallel. When the instantaneous voltage exceeds the breakdown voltage of the TVS tube, the TVS tube will avalanche breakdown, providing an ultra-low impedance path for the instantaneous current. The instantaneous current is short-circuited to GND through the TVS tube, thereby preventing large voltage signals from entering the device, and the voltage of the input signal remains at the cut-off voltage until the voltage returns to the normal range. Each signal input path has this protection circuit, and overvoltage and overcurrent protection can be performed regardless of the input method (two-wire active or passive, three-wire, four-wire, etc.).

[0055] Furthermore, the channel control switch is a PHOTOMOS tube, that is, a MOSFET output photocoupler, and the structural diagram is shown in FIG. Figure 3 As shown. The working principle is that the photoelectric element converts the light of the light-emitting element into voltage, and controls the on and off of the load circuit by turning on and off the power MOSFET. The PHOTOMOS tube does not perform mechanical closure, has high reliability, and realizes the photoelectric isolation of the controller output signal circuit and other circuits. In this device, the PHOTOMOS tube is used in the analog switch circuit to realize the on and off state switching of the channel, in the TC voltage bias circuit to realize cold end temperature compensation, and in the precision resistor control circuit. Preferably, the channel control switch, the TC voltage bias circuit, and the precision resistor sampling control circuit are all isolated by the PHOTOMOS tube.

[0056] Then, the system side circuit includes: a main controller and an IPS communication interface connected to the main controller, an RS485 communication interface, a latch circuit and a watchdog circuit. The IPS communication interface is used for information transmission between the main controller and the compensation circuit, the precision resistor control circuit and the magnetic isolation circuit; the RS485 communication interface is used for information transmission between the main controller and the signal isolation circuit. The latch circuit is used to obtain the state of the dip switch and / or control the indicator light to light up according to the control information output by the controller. The main controller is used to output control information to the latch circuit, and is also used to obtain the state of the dip switch and then control the AD sampling circuit to collect the output signal of the compensation circuit through the IPS communication interface. Figure 8 As shown, the latch circuit includes a bus transceiver U5 (model 74HC245) with input pins P0...P5 connected to the DIP switch, and output pins IO1...IO6 connected to the CPU, which are selected by the pin / ADDR_EN. The trigger U6 (model 74HC574) has input pins IO1...IO6 connected to the CPU, and output pins LED1...LED6 connected to the LED lamp, which are selected by the pin / LED_CLK.

[0057] Next, the field side circuit is also provided with an RS485 communication module respectively connected to the power supply and the system side circuit; the RS485 communication module includes: a communication interface connected to a preset external device, a signal isolation circuit connected to the system side circuit, and a power isolation module connected to the power supply; the communication interface receives control information of the preset external device and sends it to the system side circuit through the power isolation module.

[0058] The RS-485 communication module uses high-speed optical coupler devices to achieve photoelectric isolation of communication signals. The structural diagram is shown in the figure. Figure 4As shown. The input electrical signal drives the light-emitting diode to emit light, the photodiode at the output end is turned on by light, and the output end outputs the signal. Inside the optocoupler, the common-mode input voltage has little effect on the output current, so the common-mode rejection ratio is very high, which improves the anti-interference ability of the device communication module.

[0059] The field side signal needs to be isolated before entering the system side, such as Figure 5 As shown in the figure, the isolation circuit uses iCoupler magnetic isolation technology and magnetic isolation chip. The difference between magnetic isolation and optical coupler isolation is that magnetic isolation greatly eliminates a series of problems in optical couplers, such as uncertain current transfer ratio, nonlinear transmission characteristics, drift over time and temperature drift, etc., ensuring the accuracy of the signal input to the main controller after isolation and improving the reliability of the device.

[0060] Next, the field measurement circuit is also provided with a compensation circuit connected to the multi-channel signal acquisition and conditioning circuit and the system side circuit respectively. The compensation circuit is a TC voltage bias circuit for cold end temperature compensation. When there is a temperature detection signal detected by the thermocouple, the TC voltage bias circuit is activated by the dip switch to perform cold end temperature compensation. Specifically, Figure 6 As shown, the compensation circuit includes: a three-terminal voltage regulator, a first capacitor, a second capacitor, a third capacitor, a first resistor, a third resistor and a temperature compensation resistor, one end of the first capacitor and the input end of the three-terminal voltage regulator are both used as signal input ends, the output end of the three-terminal voltage regulator is simultaneously connected to one end of the second capacitor and one end of the first resistor, the other end of the first resistor is simultaneously connected to one end of the temperature compensation resistor and one end of the third resistor, the other end of the third resistor is connected to one end of the third capacitor and the temperature compensation signal output end, and the other end of the first capacitor, the ground end of the three-terminal voltage regulator, the other end of the second capacitor, the other end of the temperature compensation resistor and the other end of the third capacitor are all grounded. Among them, the model of the three-terminal voltage regulator is REF3125.

[0061] However, the system side circuit also includes: expansion and interaction circuits connected to the main controller, such as Fig. 9 As shown, the expansion and interaction circuit includes: a JTAG interface module and an LCD interface module. The JTAG interface module supports the JTAG protocol, and the LCD interface module is connected to the LCD.

[0062] In addition, an embodiment of the present invention also provides a high-reliability multi-type power front-end temperature acquisition system, including: the power front-end temperature acquisition device as described above and a host computer and / or exchange interface communicatively connected to the power front-end temperature acquisition device.

[0063] The host computer and / or the exchange interface outputs the configuration information of the sampling signal type for each signal acquisition channel to the power front-end temperature acquisition device, so that the power front-end temperature acquisition device determines the measurement signal type supported by each signal acquisition channel according to the configuration information. After the host computer configuration software or the exchange interface configures the channel sampling signal type, the configuration information is downloaded to the main controller of the device through the RS485 communication module, and the main controller determines the measured signal type according to the configuration information. The signal acquisition channel supports the acquisition of voltage signals, thermocouple signals, thermal resistor signals and resistance signals. After the host computer configuration, each channel can use different wiring methods to receive different types of signals, and the channels are isolated from each other and do not affect each other. The on-site thermal resistor signal supports three-wire connection and two-wire connection, and the three-wire measurement can eliminate the lead error.

[0064] In summary, the present invention provides a highly reliable multi-type power front-end temperature acquisition device and system. To ensure the high reliability and stability of the device, the entire system includes many isolation circuits and anti-interference measures. The isolation measures between the system side and the field side mainly include the port anti-misconnection circuit of strong electricity, PHOTOMOS tube isolation (analog switch circuit for channel switching, TC voltage bias circuit for cold end temperature compensation, precision resistor control circuit), RS485 communication module optical coupler isolation, and magnetic isolation when the field side signal enters the system side. The anti-interference measures are as follows: the signal sampling port uses common-mode, differential-mode capacitors and RC filters to eliminate high-frequency signal interference and power grid power frequency interference. The design of capacitors and RC can be designed to reasonable values ​​according to the implementation of the device to meet the EMC indicators of industrial instruments; the input signal is converted into digital form and then filtered using a digital filter to eliminate power frequency interference. Cycle filtering with an integer multiple of 20ms as the minimum unit can effectively reduce the interference of 50Hz power frequency; anti-interference components (magnetic beads) are used in key places such as signal ports and circuit board connecting lines to suppress high-frequency noise and spike interference and absorb electrostatic pulses; the loop area is reduced during wiring to reduce the noise generated by electromagnetic induction, and the power supply and grounding of the printed circuit board are arranged reasonably.

[0065] Based on the above description, the specific implementation process of the present invention is as follows: the power supply is transformed and isolated to supply power to the system side circuit and the field side circuit. The channel sampling signal type is configured point by point through the host computer configuration software. Point configuration refers to the configuration of the sampling signal type of each channel through the host computer configuration software or the exchange interface. After the port input signal passes through the anti-strong electric misconnection circuit, it passes through the RC low-pass filter circuit, and the channel control switch turns the signal acquisition channel to the on state. The signal enters the AD sampling module for analog-to-digital conversion and digital filtering. The converted digital signal is isolated by the magnetic isolation chip and then enters the main controller. In the main controller, the input signal is compared and processed with the precision resistance signal to eliminate the influence of the resistance error, and after calculation, the field temperature value to be measured is obtained. The module has its own cold end temperature compensation correction system. When the channel uses a thermocouple to measure the temperature, the cold end compensation function can be turned on or off by the dial switch according to actual needs.

[0066] Since the system / device described in the above embodiments of the present invention is a system / device used to implement the method of the above embodiments of the present invention, a person skilled in the art can understand the specific structure and deformation of the system / device based on the method described in the above embodiments of the present invention, and thus will not be described in detail here. All systems / devices used in the method of the above embodiments of the present invention belong to the scope of protection of the present invention.

[0067] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0068] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions.

[0069] It should be noted that in the claims, any reference numerals placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the claims enumerating several means, several of these means may be embodied by the same hardware. The use of the words first, second, third, etc., is for convenience of expression only and does not indicate any order. These words may be understood as part of the component name.

[0070] In addition, it should be noted that, in the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0071] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments after knowing the basic creative concept. Therefore, the claims should be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0072] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include these modifications and variations.

Claims

1. A highly reliable multi-type power front-end temperature acquisition device, characterized in that: The highly reliable multi-type power front-end temperature acquisition device is used for signal acquisition of temperature sensors in medium and large thermal power plants using a centralized control system, and supports simultaneous measurement of multi-channel and multi-type signals, including: a power supply and a system-side circuit and a field-side circuit connected to the power supply, the power supply supplies power to the system-side circuit and the field-side circuit after transformation and isolation, and the system-side circuit and the field-side circuit are communicatively connected; The field side circuit is used to control the conduction of the signal acquisition channel corresponding to each detection signal according to the signal detection information, and pre-process the detection signal, and then send the pre-processed detection signal and the precision resistance signal provided inside the field side circuit to the system side circuit; The system side circuit is used to compare and process the processed detection signal with the precision resistance signal to obtain the on-site temperature value to be measured; The field side circuit includes: a multi-channel signal acquisition and conditioning circuit and a precision resistance control circuit and a magnetic isolation circuit connected to the multi-channel signal acquisition and conditioning circuit, and the precision resistance control circuit and the magnetic isolation circuit are also connected to the system side circuit; The precision resistance control circuit is used to provide precision resistance information; The magnetic isolation circuit is used to perform magnetic isolation on the signal input into the system side circuit; The multi-channel signal acquisition and conditioning circuit is used to control the signal acquisition channels corresponding to each detection signal to be turned on when several types of signal inputs are detected, and to filter and A / D convert the detection signal, and then send the processed detection signal and the precision resistance signal obtained from the precision resistance control circuit to the system side circuit through the magnetic isolation circuit.

2. A highly reliable multi-type power front-end temperature acquisition device as claimed in claim 1, characterized in that: The multi-channel signal acquisition and conditioning circuit includes: a port anti-strong current misconnection circuit, a signal acquisition channel, a channel control switch and an AD sampling circuit; The port strong current misconnection protection circuit is arranged at the signal input end of each signal acquisition channel, and is used for overvoltage and overcurrent protection of each signal acquisition channel; The channel control switch is used to control each of the signal acquisition channels to be turned on or off; The AD sampling circuit is used to perform analog-to-digital conversion and digital filtering on the temperature detection signals received by each of the signal acquisition channels.

3. A highly reliable multi-type power front-end temperature acquisition device as claimed in claim 2, characterized in that: The port anti-strong electricity misconnection circuit includes: a bypass capacitor, a fuse and a TVS tube; one end of the bypass capacitor and one end of the fuse are both connected to the signal input end of the signal acquisition channel, the other end of the fuse is connected to one end of the TVS tube, and the other end of the bypass capacitor and the other end of the TVS tube are both grounded.

4. A highly reliable multi-type power front-end temperature acquisition device as claimed in claim 2, characterized in that: The field measurement circuit is also provided with a compensation circuit connected to the multi-channel signal acquisition and conditioning circuit and the system side circuit respectively; The compensation circuit is a TC voltage bias circuit for cold-end temperature compensation; When the temperature detection signal is detected by the thermocouple, the TC voltage bias circuit is started by the DIP switch to perform cold end temperature compensation.

5. A highly reliable multi-type power front-end temperature acquisition device as claimed in claim 1, characterized in that: The field side circuit also includes: an RS485 communication module connected to the power supply and the system side circuit respectively; The RS485 communication module includes: a communication interface connected to a preset external device, a signal isolation circuit connected to the system side circuit, and a power isolation module connected to the power supply; The communication interface is used to receive control information of a preset external device and send it to the system side circuit through the power isolation module.

6. A highly reliable multi-type power front-end temperature acquisition device as claimed in claim 4, characterized in that: The system side circuit comprises: a main controller and an IPS communication interface, an RS485 communication interface, a latch circuit and a watchdog circuit connected to the main controller; The IPS communication interface is used for information transmission between the main controller and the compensation circuit, the precision resistance control circuit and the magnetic isolation circuit; The RS485 communication interface is used for information transmission between the main controller and the signal isolation circuit of the field side circuit; The latch circuit is used to obtain the state of the DIP switch and / or control the lighting of the indicator light according to the control information output by the controller; The main controller is used to output control information to the latch circuit, and is also used to control the AD sampling circuit to collect the output signal of the compensation circuit through the IPS communication interface after obtaining the state of the dial switch.

7. A highly reliable multi-type power front-end temperature acquisition device as claimed in claim 6, characterized in that: The system side circuit also includes: an expansion and interaction circuit connected to the main controller, and the expansion and interaction circuit includes: a JTAG interface module and an LCD interface module.

8. A high-reliability multi-type power front-end temperature acquisition device according to any one of claims 1 to 7, characterized in that: The power front-end temperature acquisition device has 24 signal acquisition channels; The detection signals include: 0-20mV voltage signal, 0-100mV voltage signal, thermocouple signal, two / three-wire PT100, Cu50, PT1000 thermal resistance signal and resistance signal; the thermocouple signals include: E, J, K, N, T, B, S, R.

9. A highly reliable multi-type power front-end temperature acquisition system, characterized in that: include: The power front-end temperature acquisition device according to any one of claims 1 to 8, and a host computer and / or a switching interface connected to the power front-end temperature acquisition device in communication; The host computer and / or the switching interface is used to output configuration information of the sampling signal type for each signal acquisition channel to the power front-end temperature acquisition device, so that the power front-end temperature acquisition device determines the measurement signal type supported by each signal acquisition channel according to the configuration information.

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