You need to start the associated CIMPLICITY project in order to start the Modbus RTU Slave Interface.
To start the associated CIMPLICITY project:
Open the associated project in the CIMPLICITY Workbench.
Click Project on the Workbench menu bar.
Click the Run button on the Workbench toolbar.
Check the list of started resident processes for the name MRTUSI_RP.
Step 3. Implement the Modbus RTU Slave Configuration