[jimini]

I have my limit switches wired in series, going to pin 10.
Everything works ok when I first start, but after a while the prog. stops and says a limit switch has been tripped. It hasn't been tripped and the limit sw. led's are not lit(in the diagnostic screen), but somehow the program thinks that pin 10 has been triggered or something to give me a fault.
Any ideas where I might look?
PS. It's not a laptop!

[Greolt]

Most likely noise Jimini.

Set the debounce up to about 10,000 and see if it stops.

10,000 is really too high to leave it at but if the problem stops it will tell you it is electrical noise tripping the limit.

Then do some reading on the forum on noise issues and what to do about it.

Greg

[turmite]

I can promise you it's noise. If you are using mechanical switches, you can stop the noise by installing a small resistor across the switch leads. I think I remember it is a 1k but to be sure go to the Mach yahoo forum and do a search on limit switch noise. Or....maybe someone here can tell you what size to use. It cured my problem immediately and my system was doing the same thing as your's.

Mike

[jimini]

Thanks guys I'll give it a try, sounds like that should be it. Jim

[turmite]

jimini......forget what I told you! It is a 1uf capicator......not a resistor. I will go do a search for you to double check the size for sure and then post the info back here. Sorry about that.

Mike

[turmite]

jimini the below quote is from Mariss Fremanis from Gecko. This is a partial copy and paste of a much larger thread, but it address your problem. You will notice he said .1uf cap.

This solved my problems, but I might add I am in the process of developing enclosed optical switches for my machine and if the process is not too hard, nor expensive, I am going to offer them for sale.

Mike


"One way to use non-gold contact switches reliably at low currents is
to place a capacitor across the contacts. The cap will deliver enough
pulse current to clean the contacts on every switch clousure. This
energy is stored in the cap while the switch is open. A .1uF cap at
5VDC will store 1.25 uJ of energy, more than enough to clean any
contact. The noise filtering will probably be welcome as well.

Mariss"