User`s manual

6-7
6.5 MODBUS Communication Protocol
INP-TN5A0202-E
6.5
MODBUS Communication Protocol
The communication system with MODBUS protocol always performs communication by using the procedure that “the master
sends a command message fi rst, and the applicable slave sends a response message back”.
Communication procedure is shown in the fl ow chart below.
The master sends a command message to
the slave.
The slave checks if the station number in
the received message is the same as its
own number.
The slave throws out the message received,
and waits for the next message (No reply)
The slave runs a command, and sends the
response message
When it is the same When it is not the same