Limit switches to cut power

General discussion of using Roboclaw motor controllers
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Joe
Posts: 29
Joined: Fri Dec 23, 2016 1:00 am

Limit switches to cut power

Post by Joe » Tue Mar 27, 2018 11:51 am

For security reasons I want to use two switches additionally to the regular end switches on my linear unit. These additional switches should cut the power off. I'm using a relay module to do that.
Should I cut the power of the motors or should I cut the power of roboclaw itself?
How does roboclaw react if I cut off the power of a motor while it's running in the security switch and the power comes back when roboclaw is not resetted?

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Basicmicro Support
Posts: 1338
Joined: Thu Feb 26, 2015 9:45 pm

Re: Limit switches to cut power

Post by Basicmicro Support » Wed Mar 28, 2018 9:46 am

Depending how big the motors are you should setup a the switch to cutoff power to the motors, BUT use a diode across the switch so that reverse power can still get to the motors(eg the motors will stop when they hit the switch but the diode will allow you to reverse power to get the motors back out of the switch.

This is how many linear actuators are setup to prevent mechanical damage at the end stops.

The diode needs to support the power that will be used to back the motor out of the switch but if you limit that power it can be fairly small.

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