Example apparatus and methods to communicatively couple field devices to controllers in a process control system are disclosed. An example method of changing a communication protocol of a first field device in a process control system includes decoupling from the first field device a first removable communication module configured to communicate using a first communication protocol. The example method also includes coupling to the first field device a second removable communication module configured to communicate using a second communication protocol. After coupling the second removable communication module, the first field device is configured to communicate using the second communication protocol. In addition, the first field device is coupled to a first communication channel on an input/output card when communicating using the first communication protocol and the first field device is coupled to the first communication channel on the input/output card when communicating using the second communication protocol.