Appendix A Function code: 0x02 to read bit-device register value The data structure of function code of 0x01 is the same as that of 0x02. So 0x01will not be introduced additionally. When COM2 is possessed by PLC in DVP10MC11T, the input point status can not be read via 0x01 function code. Data structure of request message: Data structure of response message: Data structure of abnormality response message: A-20 DVP-MC operating manual Data order Name Byte Byte0 Modbus ID Single byte Byte1 Function code Single byte Byte2 The start address of DVP10MC11T bit device to be read. High byte Byte3 Low byte Byte4 The number of DVP10MC11T bit device to be read.
High byte Byte5 Low byte Byte6 Low byte of CRC check sum Low byte Byte7 High byte of CRC check sum High byte Data order Name Byte Byte0 Modbus ID Single byte Byte1 Function code Single byte Byte2 Read byte number of bit device. Single byte Byte3 Read state value of bit device. Single byte … Read state value of bit device. Single byte Byte n Read state value of bit device. Single byte Byte n+1 Low byte of CRC check sum Low byte Byte n+2 High byte of CRC check sum High byte Data order Name Byte Byte0 Modbus ID Single byte Byte1 0x80+ function code Single byte Byte2 Abnormality response message Single byte Byte3 Low byte of CRC check sum Low byte Byte4 High byte of CRC check sum High byte