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Author Topic: limit switches/ estop?  (Read 16844 times)

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Offline Hood

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Re: limit switches/ estop?
« Reply #20 on: March 12, 2009, 09:12:07 PM »
think the norm is 0.1uF , you put a cap on each input to gnd but trying it on just the troublesome one would probably do. Might be best to seek the advice of your electronics guy first.
Hood

Offline Fastest1

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Re: limit switches/ estop?
« Reply #21 on: March 12, 2009, 09:37:57 PM »
Did you see anything in my xml file?
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Offline Fastest1

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Re: limit switches/ estop?
« Reply #22 on: March 12, 2009, 10:11:07 PM »
I just checked the HCNC pro forum and Dave Rigotti, the boards designer recommended using a .01uF cap across grnd to pin used. I got 3 different .01uF caps, is there a difference I should be aware of? The types are a metalized film capacitor, a polyester film capacitor or a ceramic disc capacitor. Is 1 better or more durable than the others? They are all .01uF
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)

Offline Fastest1

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Re: limit switches/ estop?
« Reply #23 on: March 13, 2009, 12:24:54 PM »
Today I tried the .01uF cap between pin 11 and ground on the t5 on driver board. It didnt seem to help until I set the debounce 100 or above, unfortunately no matter how high I set the debounce it would still falsely trigger. With the cap in place I did notice longer delays til the false trigger. I tried as high as 10000. That gave me 30-45 seconds or so that I could actually jog the steppers without a trigger. I have seperate fuses in my chassis for the spindle, steppers, driver board, acc etc. Today I first pulled the fuse to the variable speed spindle circuit. That didnt have an effect. Put that fues back in. Then I removed the fuse for the steppers and all worked fine software wise. The board was powered up just not the steppers. So I am getting closer, I think. Any ideas? Can I increase the value in that cap and expect better noise rejection? I notice you had originally suggested a value of .1uF. I will ask specifically of the boards designer if it will cause any issues. thanks
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Offline Hood

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Re: limit switches/ estop?
« Reply #24 on: March 13, 2009, 02:50:54 PM »
Definitely sounds as if your board is prone to noise, hopefully the larger capacitors will help, also try and route any mains wiring as far away as possible from the board.
Hood

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Re: limit switches/ estop?
« Reply #25 on: March 13, 2009, 04:50:57 PM »
I am taking it you didnt see anything blatantly obvious that was incorrect in my xml? Wouldnt my xml keep changing with each setting change saved?
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Offline Hood

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Re: limit switches/ estop?
« Reply #26 on: March 13, 2009, 06:07:43 PM »
Your xml looked fine and yes it would change each time you shut down Mach with any change you had made during that session.
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Re: limit switches/ estop?
« Reply #27 on: March 13, 2009, 07:05:27 PM »
I just received a email from the boards designer that a .1uF cap was ok though he said this was a rare issue with his users. It did happen but rarely. I did add some features to my enclosure like variable speed spindle control and such. This might cause some of the interference but it didnt have an effect when I pulled the fuse. I am trying for a zero debounce, correct? I did pick up the bigger caps, so I will know more tonight. The z axis is the only one I am dealling with at the moment, under "ports and pins" input, should all 3, Z++, Z-- & Z home be enabled? I would think so but I am not sure.
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Offline Hood

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Re: limit switches/ estop?
« Reply #28 on: March 13, 2009, 07:30:19 PM »
Debounce ideally should be zero but from the looks of it you will be struggling to get that. The default of Mach used to be 500 not sure what it sets as now on a fresh install/profile.
 Yes, if you have 2 (or 3 ) switches in series for the Z axis then enable them all and set all to the same port and pin,  you can put any amount of NC limits in series so you could have all axis on the same Input pin.
Hood

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Re: limit switches/ estop?
« Reply #29 on: March 14, 2009, 01:21:32 PM »
Installed the .1uF cap on the limit switch input and ground. It didnt seem to change anything until I set the debounce to 25000. Then it would run the gcode fine without interruption (maybe). I do notice that the higher the debounce the longer time til false triggering. Also it blew a stepper fuse while I was bumping the Z+ limit, though that didnt happen again.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)