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Author Topic: Un demanded external e-stop  (Read 2880 times)

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Un demanded external e-stop
« on: September 25, 2008, 02:11:54 PM »
Hi

As a new member I am hoping someone can throw some light on to what could be causing un-demanded external e-stops on a new CNC setup. I have used a Campbell breakout board and even with all but the step motors disconnected I am getting un-demanded external e-stop triggers when the spindle motor in enabled.

I have found that by increasing the debounce time to 7000 reduces the frequency of the occurrence but does not eliminate it. Looking at the drive test shows that the computer is nice and stable. No trigger lights show prior to the e-stop when watching the diagnostic screen and if the de-bounce is set to normal levels the machine trips out after a couple os seconds run time.

At first I thought it was emf from the spindle cable but this is shielded and earthed so should reduce the chance.

1) Is pin 10 the only pin that can generate an e-stop?
2) Has anyone come across this problem before and if so what was causing it?

Many thanks

Martin

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Re: Un demanded external e-stop
« Reply #1 on: September 25, 2008, 04:04:31 PM »
Do you have limit switches? Are they shielded cables? Are the shields grounded at only one point in the control cabinet. Sounds like noise for sure.
Hood
Re: Un demanded external e-stop
« Reply #2 on: September 25, 2008, 05:14:15 PM »
Hi

With the limit switches disconnected from the breakout board ie with only the stepper motors connected the problem is still there. This almost certainly eliminates the limit switch lines as being a the cause. The only input line still connected is the e-stop and this has a temporary shorting link to eliminate any issues there.

Martin

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Re: Un demanded external e-stop
« Reply #3 on: September 25, 2008, 05:25:45 PM »
Do you still have the limits enabled in Ports and pins? Could be the breakout picking up the noise if they are.
Hood
Re: Un demanded external e-stop
« Reply #4 on: September 25, 2008, 05:52:25 PM »
Hi

With the limit switches disconnected from the breakout board ie with only the stepper motors connected the problem is still there. This almost certainly eliminates the limit switch lines as being a the cause. The only input line still connected is the e-stop and this has a temporary shorting link to eliminate any issues there.

Martin

Not so fast...  The only way to completely rule out the limit switches is to de-configure them in the Ports & Pins configuration.  Otherwise, you still have the PP Cable and breakout board which could be picking up noise.  The way to track down the source is to go to Ports and Pins and disable *everything* that doesn't have to be there to make the machine work, then turn things back on one at a time, and run it long enough to be sure whether the problem is there or not.  You may find it's not just one thing....

Regards,
Ray L.
Regards,
Ray L.
Re: Un demanded external e-stop
« Reply #5 on: September 25, 2008, 07:46:54 PM »
Good point Ray. I found with a certain C11 that pin 15 was "Leaking " through the board.
It could not be enabled at all without posing problems.
RC
Re: Un demanded external e-stop
« Reply #6 on: September 25, 2008, 10:16:39 PM »
Good point Ray. I found with a certain C11 that pin 15 was "Leaking " through the board.
It could not be enabled at all without posing problems.
RC

Yup, and grounding problems can cause all kinds of unpredictable and seemingly random behaviors as well.

Regards,
Ray L.
Regards,
Ray L.