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 FDO message to the board will force the output pin from automatic mode to hand mode and set the pin to the selected state. 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 only valid for digital output pins and can be used to set or reset the output pin.  

Possible error messages coming from the board
%FAT-UNKCMD-BTSERIAL, Unknown command received
%FDO-UNKCMD-BTSERIAL, No boolean expression
%FDO-UNKCMD-BTSERIAL, Unknown tagname received

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