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Messages - jermerf

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General Mach Discussion / Re: Limit Switch Noise Triggering
« on: August 05, 2008, 01:09:23 PM »
Yes is does.
Acutally what I did was I looked into making a brain but it wasn't, at least as far as I could tell, robust enough to work with the parallel port the way I wanted it to. Also I found that I didn't like the way the brains worked in general, not intuitive for me. So what I did is I looked into writing a VB script for a macropump. I know vb, but nothing to do with interfacing with ports. But after a bunch of research I was able to write a script that can take a user defined number of samples of each pin and average them out to a percentage of whether it was active or not, and compare that to another user defined tollerance. I was able to get on the lower end, about 95% accuracy, so I set the tollerance for 80%. It works fine now thanks.
If you hadn't suggested it, I wouldn't have tried it and I learned a lot about interfacing on the side.

General Mach Discussion / Re: Limit Switch Noise Triggering
« on: August 04, 2008, 01:27:46 PM »
I actually am already using 24 volts with relays because the limits also send a signal to my servo amplifiers. The cnc machine is in another room from where the computer is for safety, noise and cleanliness reasons. The ground looping is something i've been looking into, and I'm finding it hard to get a plain english explaination as to how to check for it quickly. It reads like a lot back to future, flux capacitor, unhappy-doom. If anyone can help with a quick way of checking that'd be great. The problem with checking is the wires are in the wall and the ceiling so it's hard to recheck the wiring. The cables are not shielded, not for the limit switches to mach anyway, but since the noise was expected, I was really just hoping low pass filtering would fix the problem. Also, I was wondering if anyone, most likely the admins etc. could tell me more about the way the debouncing is implemented. If I had to guess I'd say it wasn't really done in low pass filtering kind of way (I mean mathematical low pass filtering) and done more in an ad-hoc sort of easy fix way.
Anything, no matter how small, will help.

General Mach Discussion / Re: Limit Switch Noise Triggering
« on: August 04, 2008, 11:07:32 AM »
I thought it was too good to be true, and it was. Perhaps it was Karma.
I did what you suggested hood, and noticed mach wasn't switching back to estop. For about 3 seconds.
I tried several times with a debounce of 2000 but each time mach went back to estop within a few seconds.
I tried setting the debounce to 10,000 but that only stopped it for at most 29seconds.
I would set it higher but the kernel speed is 25khz so that would be getting closer to 1 second response time.
Would it be possible to alter the way debounce works through scripting? I was thinking I could take an average of whether mach detected the limit signal or not and compare it against a 'tollerance' constant.
But if you have any other ideas that would help.
There's also a chance it could be related to the periodic nature of the noise, but at 4khz versus 25khz, I would hardly think that debounce would get stuck given the odd-ish number.
More help?

General Mach Discussion / Limit Switch Noise Triggering
« on: August 04, 2008, 09:41:33 AM »
I'm having a problem with Mach3 recognizing noise comming in through my limit switches as a limit trigger for estop. Basically I'm using rather high power servo motors which are causing periodic noise (at a frequency of 4khz) which is contantly triggering the limit estop in mach. I have methods in place to prevent the noise affecting any other systems. The easiest thing it seems would be to use low pass filters because I don't need instantaneous estop's in mach just something fast enough, like a tenth of a second really. Is there any way in place for mach to ignore the noise on the line, or is there already some sort of low pass filter in place or something else to help not so much remove but ignore the noise? I just want something simple. I don't want to have to buy a bunch of capacitors and have to install them for filtering. Something software based would be much cheaper I think.

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