Expanding functions of a process device

A valve assembly, comprising:

• a valve including a position-lockable plug;
• a pneumatic actuator coupled with the valve;
• a valve stem connected to the valve and to the pneumatic actuator;
• a position sensor;
• a valve positioner coupled with the pneumatic actuator to deliver a pneumatic signal that causes the pneumatic actuator to change position of the valve, wherein the valve positioner is operative to identify a commanded position for the position-lockable plug in response to a control signal and a position for the valve stem from the position sensor, the valve positioner comprising,
• a housing;
• and
• a board-level assembly disposed in the housing, the board-level assembly comprising,
• a first circuit board with a microprocessor residing in the housing;
• and
• a second circuit board in communication with the first circuit board and also resident in the housing, the second circuit board removeably replaceable from the housing and the board level assembly with the position-lockable plug in its locked state and power off to the valve positioner, the second circuit board having functions that are different from the first circuit board,
• wherein, in response to a power signal, the microprocessor is configured to,
• communicate with the second circuit board when coupled with the first circuit board;
• validate operation of the second circuit board as part of the board-level assembly;
• find a storage memory on the second circuit board;
• retrieve data from the storage memory;
• and
• use the data to configure functions on the first circuit board.