GSK980TDc Turning System User:
I have connected the spindle clamp cylinder to spindle brake, Y0.7, where is M21 connection?

CNCmakers Support:
Please use single head solenoid for spindle clamp, the spindle should be loose when the solenoid without power.
Y0.7 will be turned on by executing the M20, at the moment the spindle is clamped.
Y0.7 will be turned off by executing the M21, at the moment the spindle is loosed.