Proximity switches not reliable

[alexS]

Our proximity switches are not working correctly. I dont understand why.

Having tested the following:
- all lights are on, put a wrench behind the sensor = light goes of and on in the software = ok
- checked all endstop bolts are in place and tight = ok

Here is a question:
Is there a speed limit that they actually work?
Should they stop the movement if you run at 120mm/second?

I hope I can fix this soon. My aim is to have an absolut 0 point of the shopbot based on these proximity sensors. It would be very good in an open workshop like a fablab.

Thanks for help

Alex

[Brady Watson]

Alex,
Yes - they should work at any speed. Make sure that the limit switches are ON in SB3 by checking the VN settings.

You first want to check the gap between the sensor and the target. You should aim for a 1/16" gap between the target and the sensor to make sure you get a good solid result when the sensor passes over the target. Second, you can increase the accuracy of the prox switches by grinding the head of the bolts to a V-shape & clock the ground point in the 6 and 12 o clock positions. This is more of an extreme trick & it costs next to nothing do mess around with. By reducing the target area of the bolt head you can get more consistent results.

-B

[jerry_stanek]

Make sure your VN settings are correct. On one of my machines I have normally open and on the other I have normally closed.