Wireless discrete input/output with external power option

A wireless field device for use in an industrial process, comprising:

• input/output terminals configured to couple to a process interface element;
• a discrete input/output channel configured to receive a discrete input signal from the process interface element through the input/output terminals when configured as a discrete input channel, the discrete input/output channel further configured to provide a discrete output to the process interface element through the input/output terminals when configured as a discrete output channel;
• wireless communication circuitry configured to transmit and receive information;
• a controller configured to:
• transmit information through the wireless communication circuitry based upon a process variable sensed using the process interface element;
• provide a discrete output signal to the process interface element to control a process variable in response to information received by the wireless communication circuitry when the discrete input/output channel is configured as a discrete output channel;
• receive a discrete input signal from a process variable sensor and responsively provide an output using the wireless communication circuitry when the discrete input/output channel is configured as a discrete input channel;
• an external power supply input configured to couple to an external power supply;
• a battery power supply input configured to couple to a battery;
• a two position moveable cover which covers at most one of the external power supply input and the battery power supply input;
• and
• power supply circuitry coupled to the external power supply input and the battery power supply input having a power output which powers the controller from at most one of the external power supply or the battery to thereby electrically isolate the external power supply module from the battery, wherein the power supply circuitry is responsive to a position of the moveable cover to connect the power supply circuitry to one of the external power supply input and the battery power supply input.