It sounds like you may have a physical wiring issue or a configuration/parameterization issue with the DCS.
1. Check your cabling from the DCS to the module. The network is distributed over 2-wires and connects inside the Profibus connector. If the wires are reversed you could have a lack of communication. Also, check your termination resistor switches on the connector. The switches should be turned on for the first and last device in the segment only.
2. If the DCS can’t communicate with the module, can you read it’s diagnostic information? Diagnostic information should be given by the Profibus Master. Note, the Acromag module needs to be parameterized by the DCS or Network Configuration tool so the DCS knows how to read/talk to each channel (ie; what is the TC type for each channel?). Once parameterized properly, the DCS should go out, communicate with the module, and then turn on the BUS Light to indicate the DCS is in a data-exchange mode with the unit.