Motor with electric break?

[gannicus]

Hi,

I'm trying to use this wheelchair motor with RoboClaw controller.



The wheels chair motor has extra 2 wires which connected to a electric break. I know I can always cut off the break, but if I want to use this break, how can I wire this motor to the controller?

[Basicmicro Support]

Most brakes must be energized to NOT brake the motor. Usually 12v. If you are using a larger Roboclaw you can use one of the DOUT/CTRL pins to control the brake. They can drive upto 3amps each. On smaller Roboclaws you can setup S3/S4 or S5 to control a mosfet to drive the brake. I recommend you use the mosfet we recommend for the Voltage Clamp circuit. It has already been tested to turn on fully when driven from a low voltage I/O pin.

You need to set the specific pin into brake mode(or user controlled mode) then wire 12v to one wire of the brake and the other wire to the mosfet/DOUT/CTRL pin.

[gannicus]

Hi,

Thanks for your reply, is there any more details about how can I use S3/S4 or S5 to control a mosfet? Like a wiring diagram and sample code will be great.

Regards,

[Basicmicro Support]

The mosfet wiring is identical to the circuit used for the Voltage Clamp circuit. The mosfet gate is controlled by the specificed pin(S3,S4 or S5). The brake is connected to 12v on one side and the drain of the mosfet on the other and the mosfet source connects to ground. The brake is replacing the power resistor in the voltage clamp circuit.

You can set the brake to be activated when the motor is off using the pin function settings in Ion Studio(when PWM is 0 the brake will be enabled and it will be released whenever the PWM is not 0).

I'll have to dig into a little more(its been a while) to determine how buy you can send packet serial commands to set the output state of the pin if the pin mode is set to User controlled mode. I recommend you email support@ionmc.com for more information on this capability.

[gannicus]

Hi,

Thanks for the info. I guess another approach is I can use Arduino to control a relay which controls the break and battery circuit close/open (same result as using a MOSFET I guess), energise/de energise the break before I set motor speed to zero/not zero.

[Basicmicro Support]

Yes. That would also work. However you would probably still need a transistor to drive the relay. Check the drive current required. Atmel chips can source upto 20ma IIRC but that may not be enough to drive the relay directly.