How do the proximity switches work

[archis]

I'm trying to figure out how the proximity switches work, specifcally the X axis ones. I've been look at my Buddy still can't figure out how they work.

[mark_stief]

What do you mean how to set them up or how they actually stop the the y car from falling off the rails

[dana_swift]

Jim- there are multiple answers, depending on how the question is interpreted.

As to how the shopbot uses them, there should be a bolt protruding from the drive rail that passes about 1/16" to 1/32" from the proximity sensor. When the sensor detects the bolt, either input 2 or 3 will change state and allow the SB3 program to do something appropriate.

What happens depends on how the cut file tells the SBP to interpret the proximity switches. In some cases they are ignored. In some cases it stops motion until the operator continues it, in some cases it creates a signal to let the program know it has reached a known position. (Find home)

Making the switches work depends heavily on having the bolt adjusted correctly. It needs to be within a credit-card's thickness from the sensor. There is an LED in each senor to let you know when it "sees" the bolt.

As to how the sensors themselves work, different ones work different ways, some use a miniaturized version of the same technology as a metal locator you would use on a beach, others are based on a principal called the "hall effect". The hall effect proximity sensors have a weak magnet in them and the bolt moves the magnetic field which is what is detected.

Hope one of those answers helps-

D

[archis]

Dana,

Thanks for you input, that's what I was after.

I was wondering why that one bolt stuck up so far, almost touching the powerstick. After reading your post I now get it.