RF adapter for field device with loop current bypass

A wireless adapter for use with a two-wire process control loop is configured to couple to a process field device in an industrial process control system. The wireless adapter is coupled to the two-wire process control loop and provides wireless communication to the process field device. The adapter includes first and second loop terminals configured to couple in series with the two-wire process control loop. Wireless communication circuitry is coupled to the first and second loop terminals and is adapted to provide wireless communication to the process field device. Loop current bypass circuitry is electrically connected between the first and second loop terminals and is configured to provide a loop current path therebetween in response to an open circuit in wireless communication circuitry.