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The MODBUS communication protocol for the SWP-MD80 inspection instrument is applicable to the multi-channel inspection instruments of the SWP-MD80 model produced by CHANGHUI INSTRUMENTS, those equipped with RS485 communication. http://yunrun.com.cn/upload/201911/21/201911212314015460.png 1. Data transmission format: 1 start bit, 8 data bits, 1 stop bit, no parity check bit. 2. Data format of the SWP-MD80 multi-channel inspector: 2-byte register value = binary value of the upper 8 bits of the register number + binary value of the lower 8 bits of the register. 3. Communication frame format of the SWP-MD80 multi-channel inspector: ① Register reading command format: http://yunrun.com.cn/upload/201911/21/201911212130236500.png Note 1: The starting address of the registers is 40000. ② Response: http://yunrun.com.cn/upload/201911/21/201911212130386279.png DE: Device address, (1-200), in single byte form; CRC: Check byte, using CRC-16 cyclic redundancy error checking. Note 2: Register data is in 2-byte format, with the higher bits first. Note 3: The configuration software uses different methods for calculating fixed-point numbers; some use two’s complement while others use one’s complement. Therefore, Changhui Instrument Manufacturing Co., Ltd. has added a “SWP” parameter to the primary parameters to enable switching between two’s complement and one’s complement. (0---Two’s complement ； 1---Inverted code) Example: For the MODBUS_RTU communication protocol (hexadecimal format), the transmitted data is 01,03,00,00,00,10,44,06; the received data is 1,3,20,00,01,08,00,F9,80,01,00,00,00,00,00,00,00,00,00,43,77,00,77,03,45,00,0E,8A,00,00,8A,0E,77,00,00,60,9C. The above example is for reference only; the actual communication data shall prevail. SWP-MD80 multi-channel inspection instrument dynamic data format (MODBUS_RTU protocol) ◆ The separate alarm methods are represented using 2-byte BCD codes; the first byte indicates alarms for channels 1 to 8, with 0 and 1 representing the alarm status. The format is as follows: http://yunrun.com.cn/upload/201911/21/201911212134300297.png The second digit indicates the alarm status for channels 9 to 16, with 0 and 1 representing the alarm status. The format is as follows: http://yunrun.com.cn/upload/201911/21/201911212134445541.png. The alarm format is the second byte + the first byte. It is represented as a two-byte binary number: X16 X15 X14 X13 X12 X11 X10 X9 X8 X7 X6 X5 X4 X3 X2 X1. For example, if an instrument has only 8 alarm channels, it is represented as 0000000010000000; in hexadecimal form, this is 3080. The download address for the MODBUS communication protocol for the SWP-MD80 multi-channel inspection device is: http://yunrun.com.cn/tech/2806.html