Chapter Three
Operation
Page 49
© April 2007
The Modbus configuration for unit C is shown below.
Unit C is configured with Modbus TCP Server enabled and Device ID = 1, so that the
Modbus TCP Client at B can connect and read the status of the onboard digital input. Unit C
also has Modbus TCP to RTU Gateway enabled (see section “3.13.3 Modbus TCP to RTU
Gateway”) so that the Modbus TCP Client at B can communicate with the serial Modbus
RTU device D.
The configuration of unit B is shown below (accessible via the “I/O Transfer” configuration
page).
It can be seen that Modbus TCP Client has been enabled with a 500msec scan rate, meaning
that there will be a 500msec delay between each of the mappings directed at any server. The