阅读说明：本技术 船用仪表现场自动测试系统总线 (On-site automatic test system bus for marine instrument ) 是由 金传喜 朱利文 陈盼辉 刘明辉 张龙飞 毛伟 于 2019-11-11 设计创作，主要内容包括：本发明所设计的船用仪表现场自动测试系统总线,每个槽位具有模块控制与通信总线接口、测试信号总线接口和电源总线接口,总线与电源控制模块输出功能模块的控制指令,模块控制与通信总线进行功能模块的控制指令传输,测试信号总线实现电阻源功能模块、电流采集功能模块和电压采集功能模块与被测对象之间的激励信号与响应信号的输出与输入,矩阵切换功能模块提供被测对象与测试信号总线和电源总线之间通信的信号输入与输出通道,电源总线接口给功能模块和被测对象供电。本发明较通用标准总线具有体积小、结构简单、参数设定灵活等优点,不但适用于实验室条件下自动测试,还适用于船用等空间小的现场场合。(The invention designs a ship instrument on-site automatic test system bus, each slot position is provided with a module control and communication bus interface, a test signal bus interface and a power bus interface, the bus and power control module outputs a control instruction of a function module, the module control and communication bus transmits the control instruction of the function module, the test signal bus realizes the output and input of an excitation signal and a response signal between a resistance source function module, a current acquisition function module, a voltage acquisition function module and a tested object, a matrix switching function module provides a signal input and output channel for communication between the tested object and the test signal bus and the power bus, and the power bus interface supplies power to the function module and the tested object. Compared with a universal standard bus, the universal standard bus has the advantages of small volume, simple structure, flexible parameter setting and the like, is suitable for automatic testing under laboratory conditions, and is also suitable for field occasions with small space, such as ships and the like.)

1. The utility model provides a marine instrument on-spot automatic test system bus which characterized in that: the device comprises a bus motherboard (1), a bus and power control module (2), a matrix switching function module (3), a resistance source function module (6), a current acquisition function module (7) and a voltage acquisition function module (8), wherein a plurality of slot positions are arranged on the bus motherboard (1), each slot position is provided with a module control and communication bus interface (1.1), a test signal bus interface (1.2) and a power bus interface (1.3), the module control and communication bus interface (1.1) is connected with a module control and communication bus (4), the test signal bus interface (1.2) is connected with a test signal bus (5), the power bus interface (1.3) is connected with a power bus (10), and the bus and power control module (2) is used for outputting control instructions of the resistance source function module (6), the current acquisition function module (7), the voltage acquisition function module (8) and the matrix switching function module (3), the module control and communication bus (4) is used for transmitting control instructions of the resistance source functional module (6), the current acquisition functional module (7), the voltage acquisition functional module (8) and the matrix switching functional module (3), the test signal bus (5) is used for realizing the output and input of an excitation signal and a response signal between the resistance source functional module (6), the current acquisition functional module (7) and the voltage acquisition functional module (8) and the tested object (9), the matrix switching functional module (3) is used for providing a signal input and output channel for the communication between the tested object (9) and the test signal bus (5) as well as the power supply bus (10), the power bus (10) is used for supplying power to the matrix switching functional module (3), the resistance source functional module (6), the current acquisition functional module (7), the voltage acquisition functional module (8) and the object to be tested (9).

2. The on-site automatic test system bus for ship instruments according to claim 1, characterized in that: the resistance source functional module (6) is used for generating a resistance signal as an input excitation signal of the measured object (9), the current acquisition functional module (7) is used for acquiring a current response signal output by the measured object (9), and the voltage acquisition functional module (8) is used for acquiring a voltage response signal output by the measured object (9).

3. The on-site automatic test system bus for ship instruments according to claim 1, characterized in that: the module control and communication bus (4) adopts a serial transmission mode to realize the transmission of control instructions of the resistance source functional module (6), the current acquisition functional module (7), the voltage acquisition functional module (8) and the matrix switching functional module (3).

4. The on-site automatic test system bus for ship instruments according to claim 1, characterized in that: the module control and communication bus (4) is also used for realizing the transmission of the control instruction of the function expansion module.

5. The on-site automatic test system bus for ship instruments according to claim 1, characterized in that: the test signal bus (5) is also used for realizing the output and input of an excitation signal and a response signal between the function expansion module and the tested object (9).

6. The on-site automatic test system bus for ship instruments according to claim 1, characterized in that: each frame in the control instructions of the resistance source functional module (6), the current acquisition functional module (7), the voltage acquisition functional module (8) and the matrix switching functional module (3) output by the bus and power control module (2) sequentially comprises a frame header, a signal direction, a functional module type, a mapping address, a data length, actual data, a check bit and a frame tail.

7. The on-site automatic test system bus for ship instruments according to claim 6, characterized in that: the frame header 0xff is used for identifying and positioning a frame;

the signal direction represents the signal transmission direction, the front 4 bits represent a signal sending party, the rear 4 bits represent a receiving party, and both the sending party and the receiving party can be a bus and power supply control module (2) or each functional module;

the function module type is used for identifying the type of the function module which needs to participate in communication currently;

mapping addresses: in order to ensure the high-efficiency data transmission, each functional module is allocated with a dedicated memory area in advance in the memory area of the bus and power control module (2), and when a certain functional module is accessed into the bus for use, the functional module directly transmits data with the dedicated memory area in the bus and control module (2), namely a mapping address;

the data length represents the actual data length N in the frame;

the actual data represents actual data of the communication;

the check bit is used for verifying the validity of the transmission data;

the end of frame is used to identify the end of the frame.

8. The on-site automatic test system bus for ship instruments according to claim 7, characterized in that: 0x0 in the function module type indicates a function module in which an excitation signal is generated, 0x01 indicates a current source function module, 0x02 indicates a voltage source function module, 0x03 indicates a resistance source function module, 0x04 indicates a frequency source function module, and the like; 0x0 represents a function module for collecting a response signal, including 0x10 represents a current signal collecting function module, 0x20 represents a voltage signal collecting function module, 0x30 represents a resistance signal collecting function module, and 0x40 represents a frequency signal collecting function module.

9. The on-site automatic test system bus for ship instruments according to claim 1, characterized in that: the bus motherboard (1) is provided with 6 trench positions, and the 6 trench positions are respectively and correspondingly provided with a matrix switching function module (3), a resistance source function module (6), a current acquisition function module (7), a voltage acquisition function module (8) and two function expansion modules.

Technical Field

The invention relates to the technical field of automatic test systems, in particular to a field automatic test system bus of a marine instrument.

Technical Field

The automatic test system is built by a universal standard test bus. The test bus is a medium for data transmission, processing and storage in the automatic test system, and the characteristic parameters of the test bus determine the performance of the automatic test system. At present, the test bus mainly has general bus standards such as GPIB, VXI, PXI, PXIe, LXI and AXIe. Automatic test systems are mostly built from one or more of the universal standard test buses. Each test bus has respective characteristics, and the overall performance index of the equipment based on the existing test bus standard is higher. However, since the standard test bus system is designed according to the fixed bus standard, the electrical structure and the mechanical structure of the standard test bus system have strict standards, the device size, the transmission rate, the time delay, the slot power and other characteristic parameters are fixed values, the physical size is large, the weight is generally heavier, the standard test bus system is only suitable for large or fixed maintenance test and calibration platforms, and the field maintenance test requirements of the marine instrument cannot be met, and the wiring of the universal standard test bus system adopts a front panel independent wiring mode, which is easy to cause wiring errors on one hand, and on the other hand, considering that the test device works in a marine environment with small space and shaking, in use, the situation that the contact pin is bent and cannot be used continuously may occur.

Disclosure of Invention

The invention aims to provide a bus standard of a ship instrument field automatic test system, and the bus defined by the standard has the advantages of small volume, simple structure, flexible parameter setting and the like compared with a universal standard bus, and is not only suitable for automatic test under laboratory conditions, but also suitable for field occasions with small space, such as ships and the like.

In order to achieve the purpose, the invention designs a ship instrument field automatic test system bus, which is characterized in that: the bus comprises a bus motherboard, a bus and power control module, a matrix switching function module, a resistance source function module, a current acquisition function module, a voltage acquisition function module and the like, wherein a plurality of slot positions are arranged on the bus motherboard, each slot position is provided with a module control and communication bus interface, a test signal bus interface and a power bus interface, the module control and communication bus interface is connected with a module control and communication bus, the test signal bus interface is connected with a test signal bus, the power bus interface is connected with a power bus, the bus and power control module is used for outputting control instructions of the resistance source function module, the current acquisition function module, the voltage acquisition function module and the matrix switching function module, the module control and communication bus is used for transmitting the control instructions of the resistance source function module, the current acquisition function module, the voltage acquisition function module and the matrix switching function module, the test signal bus is used for outputting and inputting excitation signals and response signals between the resistance source functional module, the current acquisition functional module, the voltage acquisition functional module and the tested object, the matrix switching functional module is used for providing signal input and output channels for communication between the tested object and the test signal bus and the power bus, and the power bus is used for supplying power to the matrix switching functional module, the resistance source functional module, the current acquisition functional module, the voltage acquisition functional module and the tested object.

The invention has the advantages of simplified bus structure, simple synchronous triggering mode and higher efficiency. The existing instrument buses such as GPIB, VXI and PXI are parallel buses, the number of connecting wires is large, the structure is complex, the design adopts a self-defined serial synchronous bus to replace the traditional computer bus mode, a single chip microcomputer system is used as a main controller, the structure of a test system is simplified, the connecting wires are reduced, and the complexity of the system is reduced. The MFTB bus adopts a message-based synchronization mode and does not need to additionally increase a synchronous clock module. The hardware triggering mode is adopted, and the triggering between the controller and the functional module is realized through hard wiring, so that the configuration is simple, the controller directly controls the triggering, and an additional complex bus arbitration mechanism is not needed.

The invention firstly moves the test signal to the bus motherboard and adopts the uniform test interface to connect with the tested object, thereby simplifying the connection and improving the reliability of the system. At present, the connection between the object to be tested and the functional module mostly adopts an external direct connection line or a mode of switching through a special adapter. But both of these approaches do not meet the field test requirements. On one hand, the wiring is more, which easily causes the condition of wiring error; on the other hand, when the test system is used, particularly on a ship which shakes, the situation that the contact pin is bent and cannot be used continuously occurs without paying attention, which does not meet the requirement of high reliability of an automatic test system; meanwhile, different tested objects have different requirements on test resources, and corresponding special adapters are needed, so that the complexity of operation is increased, and the risk of misplugging exists.

In order to simplify the connection between the tested object and the testing resource, the testing interface adopts a uniform connector. For different tested objects, the corresponding definition of the connector pins is different, namely the corresponding used test resources are different. This scheme can be implemented by adding a matrix switching function module. The matrix switching functional module transmits the test resources to corresponding test interface pins, so that one test interface is used for a plurality of tested objects. When the tested object is replaced, a user only needs to plug and unplug a test interface without connecting complex wiring.

The ship instrument field automatic test system bus designed by the invention adopts a mode of self-defining physical size, breaks through the limitation of the size of the tester in the industry, and enables the automatic test system based on the MFTB bus to be applied to field occasions with high space requirements on ships and the like; the system replaces a test bus based on computer bus extension, uses a single chip microcomputer system as a main controller, self-defines a bus, has a simple synchronous triggering mode, simplifies the system structure, reduces connecting lines, reduces the complexity of the system, has flexible parameter setting, and can realize the maximization of resource utilization; the signal connection of the functional module is firstly moved to the back plate, the tested object and the testing machine box adopt a standardized testing interface to replace a plurality of groups of independent connection lines of the traditional functional module, the complexity of connecting the bus is reduced, the reliability of the system is improved, and the volume of the bus is also reduced.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is an enlarged view of the pins of the module control and communication bus, the test signal bus and the power bus of the present invention;

FIG. 3 is an enlarged view of the leads of the object under test of the present invention;

the system comprises a bus motherboard 1, a module control and communication bus interface 1.1, a test signal bus interface 1.2, a power bus interface 1.3, a bus and power control module 2, a matrix switching function module 3, a module control and communication bus 4, a test signal bus 5, a resistance source function module 6, a current acquisition function module 7, a voltage acquisition function module 8, a tested object 9 and a power bus 10.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific examples:

the Bus (defined as MFTB Bus, Mini field test Bus) of the ship instrument field automatic test system as shown in fig. 1-3 comprises a Bus motherboard 1, a Bus and power control module 2, a matrix switching function module 3, a resistance source function module 6, a current collection function module 7 and a voltage collection function module 8, wherein the Bus motherboard 1 is provided with a plurality of slots, each slot has a module control and communication Bus interface 1.1, a test signal Bus interface 1.2 and a power Bus interface 1.3, the module control and communication Bus interface 1.1 is connected with the module control and communication Bus 4, the test signal Bus interface 1.2 is connected with the test signal Bus 5, the power Bus interface 1.3 is connected with the power Bus 10, the Bus and power control module 2 is used for outputting control commands of the resistance source function module 6, the current collection function module 7, the voltage collection function module 8 and the matrix switching function module 3, the module control and communication bus 4 is used for transmitting control instructions of the resistance source function module 6, the current collection function module 7, the voltage collection function module 8 and the matrix switching function module 3, the test signal bus 5 is used for realizing output and input of excitation signals and response signals between the resistance source function module 6, the current collection function module 7, the voltage collection function module 8 and a tested object 9, the matrix switching function module 3 is used for providing signal input and output channels for communication between the tested object 9 and the test signal bus 5 as well as the power bus 10, and the power bus 10 is used for supplying power to the matrix switching function module 3, the resistance source function module 6, the current collection function module 7, the voltage collection function module 8 and the tested object 9.

In the above technical solution, the bus and power control module 2 is composed of a control chip STM32F407, an SRAM memory chip, and a peripheral circuit.

The mechanical structure for arranging the ship instrument field automatic test system bus comprises a case and a functional module. The mode of combining the case and the plug-in functional module is adopted. The MFTB case physical dimensions are 215mm wide, 106mm deep, and 90mm high. The physical size of the MFTB functional module is defined as 1.5U, and specifically, the MFTB functional module is 20mm wide, 80mm deep and 50mm high.

In the above technical solution, the resistance source functional module 6 is configured to generate a resistance signal as an input excitation signal of the object to be measured 9, the current collection functional module 7 is configured to collect a current response signal output by the object to be measured 9, and the voltage collection functional module 8 is configured to collect a voltage response signal output by the object to be measured 9.

In the above technical solution, the module control and communication bus 4 implements transmission of control instructions of the resistance source functional module 6, the current collection functional module 7, the voltage collection functional module 8, and the matrix switching functional module 3 by using a serial transmission manner.

In the above technical solution, the module control and communication bus 4 is further configured to implement transmission of a control instruction of the function extension module.

In the above technical solution, the test signal bus 5 is further used for outputting and inputting an excitation signal and a response signal between the function expansion module and the object 9 to be tested.

In the above technical solution, each frame in the control instructions of the resistance source functional module 6, the current collection functional module 7, the voltage collection functional module 8 and the matrix switching functional module 3 output by the bus and power control module 2 sequentially includes a frame header, a signal direction, a functional module type, a mapping address, a data length, actual data, a check bit and a frame tail.

In the above technical solution, the frame header 0xff is used for identifying and positioning a frame;

the signal direction represents the signal transmission direction, the front 4 bits represent a signal sending party, the rear 4 bits represent a receiving party, and both the sending party and the receiving party can be a bus and power supply control module 2 or each functional module; 1000 denotes a controller, 0001 denotes a functional module whose physical address is denoted by 1, 0010 denotes a functional module whose physical address is denoted by 2, 0011 denotes a functional module whose physical address is denoted by 3, 0100 denotes a functional module whose physical address is denoted by 4, 0101 denotes a functional module whose physical address is denoted by 5, and 0110 denotes a functional module whose physical address is denoted by 6; for example, 0x81, indicates that the sender is the controller and the receiver is the functional module with physical address number 1, i.e. the signal is sent from the controller to the functional module with physical address number 1. It should be noted that, in order to improve the stability of transmission, the functional modules cannot communicate directly, and their communication needs to pass through the controller, that is, there are only 0x8 or 0x8, and there are no cases such as 0x12 or 0x 21;

the function module type is used for identifying the type of the function module which needs to participate in communication currently;

mapping addresses: in order to ensure the high-efficiency data transmission, each functional module is allocated with a dedicated memory area in advance in the memory area of the bus and power control module 2, when a certain functional module is accessed into the bus for use, the functional module directly transmits data with the dedicated memory area in the bus and control module 2, namely a mapping address; similar to the function module type, the number of mapped address bits increases in consideration of the possibility of using the same type of function module at the same time. The mapping address is 0x000 to represent the mapping address of the excitation signal function module, including 0x0001 to represent the current source mapping address, 0x0002 to represent the voltage source mapping address, 0x0003 to represent the resistance source mapping address, 0x0004 to represent the frequency source mapping address, etc.; 0x010 denotes the 2 nd stimulus signal function module mapping address, 0x020 denotes the 3 rd stimulus signal function module mapping address, and so on.

0x00 x0 represents a function module map address for response signal acquisition, and can support up to 15 kinds, including 0x0010 representing a current signal acquisition map address, 0x0020 representing a voltage signal acquisition map address, 0x0030 representing a resistance signal acquisition map address, 0x0040 representing a frequency signal acquisition map address, etc., 0x01 x0 representing a 2 nd function module map address for response signal acquisition, 0x02 x0 representing a 3 rd function module map address for response signal acquisition, and so on.

The data length represents the actual data length N in the frame; n is 32 at most, namely, one-time transmission, the actual data length can reach 32 bytes at most, and 0x 01-0 x20 respectively represent that the actual data length is 1 Byte-32 bytes.

The actual data represents actual data of the communication; the data content needs to be combined with the type of the functional module, and specifically comprises current, voltage, resistance, frequency and the like;

the check bit is used for verifying the validity of the transmission data; the design adopts a check sum mode to calculate the sum of the bits except the check bit as a check parameter. Only if the checksums of the sender and receiver are the same is an efficient data transmission.

The end of frame is 0xaa for identifying the end of the frame.

In the above technical solution, 0x0 in the function module types indicates a function module for generating an excitation signal, and can support at most 15 excitation signal types, 0x01 indicates a current source function module, 0x02 indicates a voltage source function module, 0x03 indicates a resistance source function module, 0x04 indicates a frequency source function module, and the like; 0x0 represents a function module for collecting response signals, and can support up to 15 kinds, including 0x10 representing a current signal collecting function module, 0x20 representing a voltage signal collecting function module, 0x30 representing a resistance signal collecting function module, and 0x40 representing a frequency signal collecting function module. It should be noted that different backplane slots may be functional modules of the same type, and therefore, during communication, a manner of combining a physical address and a functional module type is adopted, so as to avoid a race hazard in communication.

In the above technical solution, the bus motherboard 1 is provided with 6 slots, and the 6 slots are respectively and correspondingly provided with the matrix switching function module 3, the resistance source function module 6, the current collection function module 7, the voltage collection function module 8, and two function extension modules.

The bus structure of the invention is simplified, the synchronous triggering mode is simple, and the efficiency is higher:

the existing instrument buses such as GPIB, VXI and PXI are parallel buses, and have the defects of multiple connecting lines, complex structure and redundant resources. The design adopts a self-defined mode of data serial transmission and parallel transmission of a plurality of buses to replace the traditional mode of computer buses, and uses a singlechip system as a main controller, thereby simplifying the system structure, reducing the connecting lines and lowering the complexity of the system.

The MFTB bus interface is defined as follows:

the MFTB bus adopts a message-based synchronization mode and does not need to additionally increase a synchronous clock module. The hardware triggering mode is adopted, and the triggering between the controller and the functional module is realized through hard wiring, so that the configuration is simple, the controller directly controls the triggering, and an additional complex bus arbitration mechanism is not needed. The communication rate is set to 10MB/s, and the time delay is 1 us.

Naming rules of the matrix switching function module:

and connecting two ends of the matrix switching function module by using "&" to form a signal channel. For example, UUT _1& MFTB _ TS _ TEST1 indicates that pin 1 of the object under TEST is connected to the TEST signal bus 1 to form a signal path, and the signal is transmitted to the TEST signal bus 1by pin 1 of the object under TEST.

Define the meaning of each frame:

a method for testing a temperature transmitter by using the bus comprises the following scheme:

test requirements analysis is first performed. According to the test requirements of the temperature transmitter, an automatic test system is required to provide a +17V direct-current power supply, a 100-500 omega resistance excitation signal with the precision of 0.1 omega, and a 4-20 mA response direct-current signal and a 0-10V response direct-current voltage signal are required to be acquired. Therefore, the functional modules to be used include a resistance source functional module, a direct current collecting functional module, a direct voltage collecting functional module and a matrix switching functional module.

The distribution condition of pins of the connector at the tail part of the temperature transmitter is as follows:

1. physical connection

The resistance source function module, the direct current acquisition function module, the direct voltage acquisition function module and the matrix switching function module are inserted into the slot of the MFTB backplane, correspond to the slot 1, the slot 2, the slot 3 and the slot 6 respectively (Under a general condition, the matrix switching function module is placed in the slot 6), and the temperature transmitter UUT (Unit Under test) to be tested is connected with the matrix switching function module.

2. Resource allocation

And after the physical connection is completed, selecting a temperature transmitter from the upper computer program for testing, and carrying out resource configuration by the upper computer program. In the upper computer program, a temperature transmitter testing scheme is pre-stored, and key parameters of modules such as a resistance source function module, a direct current acquisition function module, a direct current voltage acquisition function module and a matrix switching function module can be configured. The method comprises the steps of configuring a resistance source function module to output a resistance scheme, such as continuously outputting 100-500 omega resistance with step length of 0.1 omega; configuring a direct current acquisition functional module to acquire the current within a range of 4-20 mA; the acquisition range of the direct-current voltage acquisition functional module is 0-10V.

3. Supplying power

The resistance source function module, the direct current collection function module, the direct current voltage collection function module and the matrix switching function module need a power bus to provide +17V direct current voltage, are specifically provided by MFTB _ PWR _ MDC and MFTB _ PWR _ MGND, and are transmitted to the resistance source function module, the direct current collection function module, the direct current voltage collection function module and the like through a power bus interface in an MFTB bus interface.

The temperature transmitter UUT is supplied with +17V dc voltage by MFTB _ PWR _ TDC and MFTB _ PWR _ TGND, and the whole process flow can be represented as MFTB _ PWR _ TDC & MFTB _ UUT _ TEST1& TIT _1 and MFTB _ PWR _ TGND & MFTB _ UUT _ TEST2& TIT _ 2.

4. Initializing and implementing basic communication

The bus and the power supply control module are sequentially communicated with the slot positions 1, 2, 3 and 6 according to the sequence of the slot positions of the backboard through a basic communication bus, the types of the functional modules corresponding to the slot positions are automatically identified, and the test requirements of the temperature transmitter are sent to the corresponding functional modules. And the functional module is initialized according to the test requirement. The specific configuration scheme is as follows:

and the resistance source functional module is configured with a resistance signal output channel, outputs through the MFTB _ TS _ TEST1 and the MFTB _ TS _ TEST2, correspondingly configures MFTB _ UUT _ TEST3 and MFTB _ UUT _ TEST4 of the matrix switching functional module, and finally transmits to pins TIT _3 and TIT _4 corresponding to the temperature transmitter, wherein the whole process can be represented as MFTB _ TS _ TEST1& MFTB _ UUT _ TEST3& TIT _3 and MFTB _ TS _ TEST2& MFTB _ UUT _ TEST4& TIT _ 4.

The direct current acquisition function module is configured with a current acquisition channel, the test system acquires signals generated by the temperature transmitter, and the signal direction is from the UUT to the test system. Pins TIT _5 and TIT _6 of the temperature transmitter are configured, MFTB _ UUT _ TEST5 and MFTB _ UUT _ TEST6 of the matrix switching function module are correspondingly configured, and finally the pins are sent to TEST signal buses MFTB _ TS _ TEST3 and MFTB _ TS _ TEST 4. The flow may be represented as TIT _5& MFTB _ UUT _ TEST5& MFTB _ TS _ TEST3 and TIT _6& MFTB _ UUT _ TEST6& MFTB _ TS _ TEST 4.

The direct current voltage acquisition function module is configured with a voltage acquisition channel, and the test system acquires signals generated by the temperature transmitter, so that the direction of the signals is from the UUT to the test system. Pins TIT _7 and TIT _8 of the temperature transmitter are configured, MFTB _ UUT _ TEST7 and MFTB _ UUT _ TEST8 of the matrix switching function module are correspondingly configured, and finally the pins are sent to TEST signal buses MFTB _ TS _ TEST5 and MFTB _ TS _ TEST 6. The flow may be represented as TIT _7& MFTB _ UUT _ TEST7& MFTB _ TS _ TEST5 and TIT _8& MFTB _ UUT _ TEST8& MFTB _ TS _ TEST 6.

And the matrix switching functional module drives the corresponding relay according to the connection relation.

5. Implement functions

After initialization is complete, testing will begin. The testing procedure is described by taking the value point of 100.0 Ω of the temperature transmitter as an example.

The method comprises the following steps: a communication establishment procedure. The bus and power supply control module enables the resistance source function module through a hardware interrupt line MFTB _ CC _ TRIG, and after receiving an enabling signal, the resistance source function module establishes communication with the bus and power supply control module;

step two: and sending the resistance value. After communication is established, under the control of the bus and the power control module, the resistance source function module sends a resistance value signal of 100 ohms, the signal is sent to the matrix switching function module through buses MFTB _ TS _ TEST1 and MFTB _ TS _ TEST2, then the signal is switched to MFTB _ UUT _ TEST3 and MFTB _ UUT _ TEST4 through the matrix switching function module, and finally the signal is transmitted to corresponding pins TIT _3 and TIT _4 of the temperature transmitter;

step three: in response to the feedback process. And after receiving the resistance signal, the temperature transmitter performs a series of signal transformation and finally outputs 4-20 mA direct current. The response direct current flows through pins TIT _5 and TIT _6 of the temperature transmitter, is transmitted to MFTB _ UUT _ TEST5 and MFTB _ UUT _ TEST6 of the matrix switching functional module, is switched to TEST signal buses MFTB _ TS _ TEST3 and MFTB _ TS _ TEST4 by the matrix switching functional module, and is collected by the direct current collecting functional module finally. At this time, the bus and power control module inquires the direct current acquisition function module every 1s to determine whether the acquisition is completed. When the current signal is acquired, the bus and power supply control module sends a data request, and the direct current acquisition functional module transmits a current magnitude signal to the bus and power supply control module through the basic communication bus;

step four: and evaluating and analyzing test results. And the bus and power supply control module analyzes the received current magnitude signal. If the deviation of the current magnitude signal and the theoretical output value is within the allowable error range, the 100.0 omega numerical value point of the temperature transmitter passes the test, and the test is finished; if the deviation of the current magnitude signal and the theoretical output value exceeds the allowable error range or the output is zero, the temperature transmitter does not pass the test, and at the moment, the test needs to be carried out by combining the middle test point of the temperature transmitter;

step five: and testing the middle test point. When the temperature transmitter fails to pass the test, the voltage test can be carried out through the middle test point, so that the fault diagnosis can be conveniently carried out, and the fault diagnosis range can be reduced. The bus and power supply control module enables the direct-current voltage acquisition functional module through the MFTB _ CC _ TRIG. And the direct current voltage acquisition functional module enters a data receiving state. The voltage signals are output by pins TIT _7 and TIT _8 of the temperature transmitter, enter MFTB _ UUT _ TEST7 and MFTB _ UUT _ TEST8 of the matrix switching functional module, are switched to MFTB _ TS _ TEST5 and MFTB _ TS _ TEST6 by the matrix switching functional module, and are collected by the direct-current voltage collecting functional module. The bus and power control module inquires the direct current voltage acquisition function module every 1s to determine whether the acquisition is finished. When the voltage signal is acquired, the bus and power supply control module sends a data request, and the direct-current voltage acquisition functional module transmits a voltage signal to the bus and power supply control module through the basic communication bus. The bus and the power supply control module carry out analysis, if the deviation of the voltage signal and the theoretical output value is within an allowable error range, the circuit of the temperature transmitter which is input to the middle point through the resistor is a circuit which can work normally, and a fault can be positioned to the middle point to a current output part circuit; if the deviation of the voltage signal and the theoretical output value exceeds the allowable error range or the output is zero, the circuit of the temperature transmitter resistor input to the intermediate point has a fault, but the circuit from the intermediate point to the current output part needs to be further verified.

Details not described in this specification are within the skill of the art that are well known to those skilled in the art.