Disable stepper on 3 axis machine

Controllers Smoothie
1

Is there any way to disable a stepper driver when there is no motor connected?
I have a 3 axis cnc but a 4 axis board and I don’t want to fry the driver if I give a command to the motor by mistake

I tried settings these settings as follows:
extruder.hotend.enable false
delta_current 0.0

Imported from wikidot

2

There is no risk of burning anything if there is nothing connected to it.

And yes, setting the current to 0 disables it.