Fanuc external control of 7th axis brake

Hello,

I am using a M-20ia 35M robot with a R-30ib Plus Controller.

I have a 7th axis setup in group 2 with its own brake.

I also have an external brake to backlash on the table. (There are two gear reducers)

I am trying to get the robot to manually engage/disengage its break whenever the external brake is engaged/disengaged.

Right now I am attempting to us BG logic to do this however I cannot seem to find the correct variable to use.

I have found the variable $MCR$BRK_OUT_ENB which allows me to manually engage or disengage the 7th axis brake however it also enables/disables the other 6 axis in group 1.

Is there a way I can specify which axis is controlled by this variable?

My understanding is that the backlash comes from the second reducer since it is belt driven. When the servo is on there is still backlash because although the servo rotor is not moving due to the brake we can still move the table a little bit. Hopefully that will help you understand. After contacting fanuc and asking about using variables in BG logic they told me that it is not possible so we have abandoned the idea all together. Thank you for your response.