HenryDUT wrote:Thanks for fmunhoz's recommendation.
In MODBUS Messaging on TCP/IP Implementation Guide, it says that
On TCP/IP, the MODBUS server is addressed using its IP address; therefore, the MODBUS Unit Identifier is useless. The value 0xFF has to be used.
When addressing a MODBUS server connected directly to a TCP/IP network, it’s recommended not using a significant MODBUS slave address in the “Unit Identifier” field. 0xFF is recommended for the “Unit Identifier" as non-significant value.
But 0xFF is greater than 247 (decimal), how can I assign 0xFF to the slave device address?
Who can help me?