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Author Topic: Limit switch engages when I start my router?  (Read 3220 times)

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Limit switch engages when I start my router?
« on: April 14, 2008, 10:43:04 PM »
I can run a program with my Vari speed Bosch router off with no problem but as soon as I turn it on the reset button blinks and says a limit switch has triggered but when I look at the diagnostic page no switch shows it has been triggered.
I cam then hit the reset button and cut to my liking but occasionally it will kick back into safety mode but there is no indication as to what is causing this?
Is it stray RF off the router motor?
When I first built my machine it did this like crazy then I used sheilded cable for the limit switches and it got 90% better but I still have this annoying seemingly random occurance...EXCEPT when I turn my router on which is not random at all it will kick out to safety every time it is powered up ...what gives?
Any suggestions are greatly appreciated!!!
Re: Limit switch engages when I start my router?
« Reply #1 on: April 15, 2008, 12:00:23 AM »
I had the same problem, still do every once and a while if I chuck a really huge bit and start bouncing the gantrys around a lot.  At first I thought it was my cheapie limit switches-Nope.  Then I tried increasing the DEBOUNCE setting on the general config page to around 2000Ms.  That helped tremendously and except for the big bit thing- problem went away.

Abot a month ago it started again and eventually I ran it down (with the guys from PMDX) to trouble with my breakout board.  Are your runing a PMDX 131?

Try debounce first and see if that helps.

Good luck,

Offline GPDC

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Re: Limit switch engages when I start my router?
« Reply #2 on: April 15, 2008, 11:03:50 AM »
I had the same problem, and I have shielded cables etc etc etc. here was the solution:
1-I have my limit switches switching 24Vdc, relays, but you can use 12Vdc or whatever the voltage you have available , just don't forget to put a diode reversed biased in parallel with the relay coil (the positive of the power supply goes to the stripe of the diode).
When wiring the relay coil put a Normally Closed push button in series with the positive wire, to be your  over travel Bypass button , so you can push it while you jog your axis out of the over travel condition.
2-Use the Normally Open Contact of this relay to send back to your input the OV from the pin 18 to 25 of the parallel port
3-Use the Normally Open contact of your limit switches to drive the relay.
4- Set your pins to activate on Low.
5- Enjoy your machine and be happy!
I did this and I have been sleeping better ever since!
good luck!
Re: Limit switch engages when I start my router?
« Reply #3 on: April 15, 2008, 09:41:52 PM »
Thanks Gents!
I checked my debounce setting and it was set to zero...changed to the suggest setting from Sid and low and behold it worked perfectly!!!
Thank you ! you saved me some headache!!
Richard your solution sounds excellent as well I can see from your description that the controller sees only the normally closed side of the relay so that the wires and limit switches can pick up all noise in the world but its not until the limit switch has been mechanically triggered that the relay will react and trigger the controller.
If I continue to get the ghost trigger even after the debounce setting has been tried I will probably take your suggestion
and isolate the controller thru the relays.