WI-MOD-E-100 & WI-MOD-E-300 Wireless Ethernet
User Manual
WI-MOD-E Manual v1.10
Page
56
An example of the ModBus functionality of the WI-MOD-E is illustrated below. In this example the
status of the onboard digital input at C will be reflected at the onboard digital output at B. Also, 8
I/O registers from ModBus serial device D will be transferred to A.
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 “Reset
Registers on Comm.’s Fail” option is enabled with a timeout of 60 seconds, indicating that any of
the registers at unit B will be reset if a successful ModBus transaction involving that register has not
been executed in the last 60 seconds. The ModBus TCP to RTU Gateway at B must also be enabled
(see section “3.13.3 ModBus TCP to RTU Gateway”) to allow ModBus communications with the
serial device A.
Three “ModBus TCP Client Mappings” are also configured at B in order to perform the required I/O
transfer. The first mapping transfers the status of the onboard digital input at C to the onboard