How to Wire a Stepper Motor Brake (Back to Wall Mounting)

Hey Justin,

in a datasheet of a stepper driver that supports motors with brake, you can find the conditions in which you want the brake to be activated:

Brake is fixed at:

  • Alarm Signal active
  • Enable Signal inactive
  • Error in the power connection of the motor
  • Error in the power connection of the brake

This means, you would need a logic that checks these four points, that are the cases where the system itself still has power (not the “hard” power cutoff of entire system) but you need to have the brake activated (you want that when the stepper’s electromagnetic detent / holding current is gone for some reason to prevent movable parts move by themselves because of gravity then).

The question is how works Emergency Stop on your system.

On the Masso-G3-Touch-based Onefinity Elite Series, the Emergency Stop Button(s) are directly connected to the “Enable” pins of all motor drivers (see motor driver specs) (besides being connected to the “ESTOP” input of the Masso G3 Controller, which in turn activates its “ES” output that controls the two relays inside the Elite Power Supply Box which interrupt the power supply sockets for “Router” and “Vacuum”. Note: The DC power supply sockets for the stepper motors in the Elite Power Supply Box are not powered off when hitting Emergency Stop Button!)

See also Elite stepper motor and driver specs for “Enable” and “Alarm” pins.

That’s just a summary of the facts you need to know in order to find a solution.

On the Buildbotics-derived Onefinity Controller on the Onefinity X-35/X-50 Series, Onefinity does not make use of the hardware input for triggering the “Estopped” mode. The big red button on top of the Controller Box is not triggering “Estopped” mode (as confirmed here), which means, hitting the big red button on top of the box will not take care to stop the router or the spindle!

But the Controller’s “Estopped” mode *will* take care to stop the router (if it is connected over a relay to ‘tool-enable’ on pin 15 of the 25-pin I/O port) and the spindle (by sending the VFD “STOP” command via ModBus over the RS-485 serial communications port on pins 10 and 11).

For this reason, it is always a good idea to wire a big red mushroom-shaped button to the “estop” input on pin 23 of the 25-pin I/O port and make it accessible near the machine operator.

(to be continued, got to leave for one moment)