The finite state machine normally controls the outputs. This is called automatic mode. With the HMI functionality it is possible to force outputs to a certain state. Sending a FAO message to the board will force the analogue output pin from automatic mode to hand mode and set the pin to the selected value. So, the finite state machine has no longer influence on the activation of the pin. With the “Reset to Automatic (RTA)” function, the pin is set to automatic mode again[1]. The function is valid for analogue output pins and can be used to set a fixed value on the pin.  

Possible error messages coming from the board
%FAT-UNKCMD-BTSERIAL, Unknown command received
%FAO-UNKCMD-BTSERIAL, No valid value
%FAO-UNKCMD-BTSERIAL, Unknown tagname received

[1] When set to automatic, the value of the pin keeps the forced value until changed by the FSM.