Write Command - Protech Systems SI-W509 User Manual

4.1.2 WRITE Command

Command Format
ID
1 Byte
• ID: The Slave Device address is from 0 to 255.
• CMD: The Modbus commands are as 0x05, 0x06, 0x42...
• Address: The mapping address of register definition for SI-W509
Series.
• Data: Data Packet
• CRC: Cyclical Redundancy Check is produced by Modbus utility.
Response
ID
1 Byte
• ID: The Slave Device address is from 0 to 255.
• CMD: The command code is the same as Read command.
• Length: The data length
• Data: The responded data for the CMD
• CRC: Cyclical Redundancy Check is produced by firmware.
Error Response
ID
1 Byte
• ID: The Slave Device address is from 0 to 255.
• CMD: The command code is the same as Read command.
• Address: The address of register definition for SI-W509 Series.
• Data: Error Code
• CRC: Cyclical Redundancy Check is produced by firmware.
*If a CRC is mismatched, the module will not respond.
SI-W509 SERIES USER MANUAL
CMD Address
1 Byte 2 Bytes
CMD
1 Byte
CMD Address
1 Byte 2 Bytes
Chapter 4 MODBUS RTU Protocol
Data
2 Bytes
Length Data
1 Byte N-Byte
Data
2 Bytes
CRC
2Bytes
CRC
2 Bytes
CRC
2 Bytes
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