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Re: Limit switches are tripping randomly during machine operation
Posted: Sun Jan 27, 2019 10:26 pm
by Gary Campbell
I agree with most everything in that article, and this one also from 2002:
https://www.amazon.com/Woodshop-Dust-Co ... 1561584991
That said, neither apply, nor do they mention CNC requirements. They are geared at the possibility of explosion in a home shop dust collection system, which is very low or nonexistent. Simple test: Remove the dust collection hose from the CNC machine and rerun the file
Re: Limit switches are tripping randomly during machine operation
Posted: Sun Jan 27, 2019 10:29 pm
by slodat
It has been running for 54 minutes since last trip. It’s not the dust collection (I think). It has done it (once I recall for sure) without dust collection.
Re: Limit switches are tripping randomly during machine operation
Posted: Sun Jan 27, 2019 11:20 pm
by slodat
Ran the last program without incident. I looked at the error log and there are many entries for the limit switch trip. It shows all three. Has me thinking there's something common to them, but I'm not sure what's up with that yet. Report and config photo attached.
Re: Limit switches are tripping randomly during machine operation
Posted: Mon Jan 28, 2019 6:48 am
by mick41zxr
Check with Keith,
I think there is an issue with home/limitOk setup at moment. I had an issue where home/limit kept re-tripping on axis 1 across a variety of switch types.
Only happened in first axis. Changed setup to home all & problem went away, just used soft limits after that.
Regards,
Michael
Re: Limit switches are tripping randomly during machine operation
Posted: Mon Jan 28, 2019 1:54 pm
by slodat
Michael,
So I can switch the inputs to be home only and then use travel limits to handle the limit piece..? Hadn't thought of that. Hopefully Keith will weigh in.
Thank you!
Re: Limit switches are tripping randomly during machine operation
Posted: Tue Jan 29, 2019 4:47 am
by mick41zxr
Yes,
Wire them in series to one input, set it to HomeAll & control travels with soft limits.
Regards,
Michael
Re: Limit switches are tripping randomly during machine operation
Posted: Tue Jan 29, 2019 11:31 am
by cncman172
slodat,
Another options is to make your limit switches use 24V logic. Use a 24V relay and have the 24V flow through the NC contacts of the limit switches to and to 24V power supply. When the limit switch or all the limit switches if you choose to wire them all in series are NC not being touched at any extreme, the 24V power will energize a 24V relay. Not the 24V relay on the Acorn board a stand alone relay. The contacts of that relay will be wired to the input on Acorn selected for limits. This will keep all the limits well above the noise level and you will not see any limits firing with dust collection or anything else. This is a common practice on many commercial machines.
Russ
Re: Limit switches are tripping randomly during machine operation
Posted: Wed Jan 30, 2019 10:37 am
by slodat
I changed the inputs to HomeOk for each of the three axis.
Re: Limit switches are tripping randomly during machine operation
Posted: Wed Jan 30, 2019 11:26 pm
by slodat
Keith?
Re: Limit switches are tripping randomly during machine operation
Posted: Thu Jan 31, 2019 10:50 am
by cnckeith
hello.
we do not recommend using NO switches as they are susceptible to noise. use NC switches and 24 vdc.