In the station control system of Gezhouba converter station, ABB's 70PR02 programmable logic control processing module is used. This module is used to solve general control tasks, and can also be used alone or coupled with other controllers and processors on the local bus. The input and output of data is completed by P13 local bus communication controller, and the programming is using the P10 functional language developed by ABB, which is easy to learn. This module also has the basic functions of controlling the application, and the user can specify its own combined functions.
1 The storage process of the programThere is a PROGR key on the panel of the 70PR02 module that can be inserted into the test memory 70SP02. It can be used in conjunction with the programming box 70SK02 or 70SK03 to realize programming and debugging the user instruction list, and it can also read the instruction list and modify it. It is also possible to modify and adjust compound function commands.
1.1 Instruction list
The instruction list is a program written by the user. This program is written in P10 language. Including the call of basic function blocks and compound function blocks. The memory storing these instruction lists is two parallel EPROMs. The storage range can be 2 048 rows or 4 096 rows. Select by jumper plug S41.
The program ends with the command "END". If for some reason, the command "END" is not processed for more than 120 ms, then all the outputs to the local bus are blocked at this time, and an internal fault signal SME is generated, and the alarm lamp ALARM gives an indication.
1.2 List of composite functions
The compound function block is a function block that is compiled by users in P10 language and is frequently used repeatedly. It is called by the instruction list, as long as it does not exceed the storage capacity of the memory, any number of compound function blocks can be stored in the program memory. However, only 64 compound function blocks can be called in the instruction list (including repeated calls of one compound function block). The storage capacity is 2 048 rows or 4 096 rows, which can be selected by jumper plug S42.
The storage range of the compound function command can be selected by the position of the S42 jumper plug (2 048 lines or 4 096 lines).
The flow of program storage is shown in Figure 1.
Fig. 1 Program storage flow chart
2 program processingThe programming box 70SK03 or 70SK04 transfers the instructions written by the user to the storage unit of the 70PR02 module through the PROGR input port. After the signal exchange, signal processing will be carried out. The processing part is composed of TTL-LS integrated circuits. The core component is 28S42N And 18S130N type PROM to realize this function, in its microprogrammer stores processing instructions and service programs for basic functions. The processing part cooperates with the data memory to process the instruction list and the instructions of the compound function list in the program memory.
2.1 Working sequence of program processing
About 10 ms after the module is powered on, the program is ready and ready to start. In the following cases, initialization is required after startup: â‘ Turn on the power supply US; â‘¡The address of the local bus is disturbed; â‘¢When the module has various test memories, the button "RAM" or "PROM IN ACTION" on it is Press it to switch from EPROM to test memory.
The initialization completes the following tasks:
In the first 35 cycles (700 ms), all function blocks are initialized. During this time and the following 10 cycles (200 ms), the output of the module to the local bus is blocked.
2.2 Processing of input and output data
At the beginning of the processing cycle, data is exchanged first. The number of data words exchanged can be adjusted by jumper plugs S21~S32. The number of data words exchanged, that is, the addresses of each data word are 32, 64, and 128 respectively.
After the data exchange, run the service program. After the service program is processed, the instruction list is processed immediately until the "program end" instruction END is processed.
The function block "COED" performs the following functions:
Record the set "A0, A1" output by the module to bits 3 and 4 of the internal data storage area 00 unit, and run the "watchdog" program to make the processing cycle run. After the function block "COED" is processed, the processing part of the module will wait for the next new processing cycle.
3 Data storage3.1 Bus data storage area
The bus data storage area occupies 128 units of 16 bits; the address is 00~7F, and each processing cycle must read in the local bus data through the local bus interface and send the processed data results to the local bus . These are all realized by identifying the information word of the traffic manager 70BV01 on the local bus through the interface. The data call and data storage of the processing part to the data storage area are called and stored bit by bit through instructions with prefixes 4, 5, 8 and B. The functions of the 4 prefixes are as follows: 4 is a positive input that calls the serial data line DN; 5 is a negative input that calls the inverted serial data line DI; 8 and B are deposits.
The data in this storage area can be indicated and simulated by the service equipment.
3.2 Internal data storage area
The internal data storage area occupies 128 units of 16-bit memory, the address is 00~7F, for the user program as an intermediate effective storage, they call the instructions with prefixes 2, 3, A bit by bit through the command table .
3.3 Past value storage area
The past value storage area occupies a 12-bit memory. 1 024 units store some special function data, such as time-related or status input module data, users cannot directly access them
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