Configurations for Limit and Home Switches

Summary of videoThis two-minute video explains the general configuration for Limit and Home switches. The diagrams are explained by a MachMotion technician.

Video Transcript:

0:08 On today's video we're going to be discussing different configurations for limit and home switches. The most common limit switch configuration that is used is for normally closed circuit. You'll have one switch on either end of the travel. So when, in this case the gantry moves, it hits the switch on either end to give you your over-travel limit. So you'll have 24Volts go into your motion control or coming from your motion controller to the switch, and it's wired in series here to the next one and loops back and goes into your signal input for whichever access limit switch you’re using.

0:45 This configuration is also, let's you home it. So either one of these switches can be used to home the axis, and it just looks for the signal. When it's homing, it knows that when it gets a signal, it's a home signal. Otherwise, if it's not in a homing sequence, it treats it as an over-travel. Okay, this is the other primary configuration we have. Often, we'll see this on a Z axis. So, you know, ignore the mechanics of it but--so you have some tabs on either end of the travel. So it comes up, hits, comes down, hits, so this one switch is your positive limit switch, your negative limit switch, and your home switch all together. You’ve got the same 24Volts signal and signal input for your wiring and relatively simple and straightforward. There are other configurations that can be used, all of these circuits that I've shown you are normally closed circuits.

1:38 You can use normally open. We don't recommend that because of safety considerations, but the motion controllers and everything are configurable for just about anything you can think of. But these two are the most common and the ones that we recommend. I hope you found this video informative. If you would like to find out more about MachMotion, you can visit us at and watch our other videos.