Hi All

i have a dodgy limit switch... but not to sure which one... the problem arrises once every 2-3 hours or so ... but some times can happen in 10 minutes......

the history screen only tells me tha it was a limit but not which one .....

any ideas

Disable one at a time and test.
Hood

it just can take a really long time to show the error... i never know if i have got the prob or not....sometime a whole day will go by no prob

How do you have your limits input to Mach? are they all on the same pin or on seperate pins? If seperate you could possibly set up a Brain to switch  on and latch a  User LED if it sees a limit.
Hood

they are on seperate lines ....

but the brain bit is over my head

The Brain is easy enough to do but whether it would catch it would depend on how long the limit is seen for, also the latching in the brains can be problematic. I would soon write a Brain up if you coulnt manage.

Is this a new problem that has just started on a previously good system or is it a new system and the problem has been there since day 1?
If the latter then could just be noise or a bouncy switch and if thats the case then you could try increasing the Debounce Interval.
Hood

it has been there since day 1 .... but there was come problems with some of the switches and they got replaced( visible mechanical damage)  and the replacements look ok but there could be cable damage that is positional

I tried a Brain last night but afraid I couldnt get the latching to work properly so have tried a macropump and that is working fine.
 You would need to add some LEDs or  DROs to the screen to see which switch had triggered. Let me know if you want to try this and I can help you further.
Hood