Using b3 PowerFail System Variable in Script programs


PowerFail System Variable for b3 controllers does not show correct value in Script Editor Binding Variables Window

Product Line

SmartStruxure Solution


Schneider Electric b3 controllers


The script program editor for b3 controllers does not recognize the PowerFail system variable as a system-defined value. The value of the variable can still be used in a b3 Script program by creating a Numeric Input in the program header, and then binding the SystemVariable to the program.    

Once the value is bound however, the value of the PowerFail System variable is not displayed correctly in the program editor Binding Variables display window.

The value of the PowerFail system variable should be shown as a binary value – either 0/1, ON/OFF or True/False.  Instead, the Normal (OFF) value displays as the integer value “1536”.


Although its value is not displayed correctly Binding Variables display window, when the object is bound to the program the value of the object is correctly interpreted when the program is compiled and executed.

For coding purposes, the numeric should be treated as a binary value with the expected values of ON and OFF.  Do not use the integer value shown in the Binding Variables window.

Example would be :

If PowerFail = On then Goto DelayStart

Note : The PowerFail system variable in a b3 controller is only active for ONE scan FOLLOWING the restoration of power following a power loss to that controller.