GFK-2423G
Nov 2019
10
As before, to trigger the command, the sequence number, %AQ0002 must be incremented.
When the sequence number in %AI0002 matches the value sent in %AQ0002, it checks the command status value. If
the command status value in %AI0001 is 1, the command has been successfully executed. The Serial Communications
Module has successfully transmitted the Modbus RTU command to RTU Slave Device 3.
RTU Master Commands Supported
The Serial Communications module supports RTU Master command numbers 65520, 8000, 8001, 8002, and 8003 as
described in the
Modbus RTU Communications Manual,
GFK-2220, with a few differences as described below.
Command 65520
–
Initialize RTU Master Port
If it is necessary to change the serial port settings from the default values, the Initialize RTU Master Port command can
be sent to the Serial Communications module by placing the values shown below into the module’s configured %AQ
memory references. The module returns the status of the request in the first word of its configured %AI memory
references and the command’s sequence number in the second word.