Hello Guest it is July 17, 2019, 09:46:06 AM

Author Topic: homing and limits  (Read 3938 times)

0 Members and 1 Guest are viewing this topic.

homing and limits
« on: October 28, 2009, 05:39:43 PM »
Can any one help ??   

iv been having a hard Time with my homing and limits i can make them work just fine.  i can jog about as much as i like at any speed and last night i was drawing road runner no problem at all. But to night i had a center drill in the chuck on alloy doing the same but now i keep getting limit or estop all the time turn them of but keep homing on and the machine will give me a full roadrunner ???

what can this be do you thing the inverter is killing of bad HZ iv been having this sort of problem before but i seem to of got round it but its come back I'm lost and am starting to not see the light at the end any more and iv not even made a part yet?

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: homing and limits
« Reply #1 on: October 28, 2009, 05:55:47 PM »
Increase the Debounce Interval to 2000 and see if that helps. If it does reduce until it happens again then bump back up a bit.
Best way however is to make sure your limit wires are properly shielded and maybe also a filter on to your VFD would help.
Hood
Re: homing and limits
« Reply #2 on: October 28, 2009, 06:26:18 PM »
is the debounce the one in the config screen in the top right if so i all ready have that up to 2500 ?  would ferrite rings all so help with things as well on my switch wires and i thing ill look in to a fillter for my vdf as well

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: homing and limits
« Reply #3 on: October 28, 2009, 06:33:52 PM »
Best to have shielded cables on your limit switch wires and try as much as possible to route them away from any mains voltage wires. Any signal wires that are 5v are very susceptible to noise and really need properly shielded and grounded. Twisting the wires can help but really its a poor substitute for shielding. Twisting the power wires from and to the VFD may also help. Having your limits work on 24v volt and then converting to 5v just before your breakout is the best option and it is what I do.

Hood
Re: homing and limits
« Reply #4 on: October 28, 2009, 06:56:27 PM »
Mmmmm that has made me think as the wires for the estop run up the same tube as the motor wires ill move it all i think.  how do you drop from 24 to 5 volts i like the sound of all that

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: homing and limits
« Reply #5 on: October 28, 2009, 07:02:38 PM »
I just use a relay board I made up for the limits.
Hood
Re: homing and limits
« Reply #6 on: October 29, 2009, 04:28:48 PM »
I see what you have done that looks intresting.  

I tryed to run my machine to night after making a new data lead for my switch's and i all so removed all my wires from my vdf from out of the machine and have run them out side just for no totally away from every thing and this has made no difference.  but when i tryed to do a road runner with out the spindle going it did for 4 runs with out tripping it then 2 one after the other it started playing me about once more?  so iv read some wear that you can take 5 volts from a usb and use that to help back up the break out board is this true and if so wear do i run the wires to  :-\  iv now got debounce up to 5000 and still wont play ball 

http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=203

Or i have just found this would this buffer boread better for me just to hump the amps and volts up to get that cleaner line
« Last Edit: October 29, 2009, 04:43:07 PM by hudmut »

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: homing and limits
« Reply #7 on: October 29, 2009, 05:09:57 PM »
Never used a CNC4PC BOB, the one I use is a PMDX122, I first got one for the Bridgeport I converted and it worked very well so I got one for the next Bridgeport, one for the Lathe, one for the coilwinder and one for the mill I am now doing and all have worked flawlessly for me.
 It definitely seems noise from the VFD is an issue but as it has also given problems without the VFD running your issues go deeper. Your 5v signal wires really need to be shielded and the shielding grounded at only one end and all grounded to the same point.
As a test however is it possible for you to disconnect the limits from the BOB and change the active state in Ports and Pins and see what happens there.
Hood
Re: homing and limits
« Reply #8 on: October 29, 2009, 06:45:44 PM »
yes if i turn all the limits of and leave homing on it will work fine as soon as i start adding in limits it gets up set.  i made all new shielded leads to day at work i think a lot of it is starting to come down to a weak signal and my vdf like you say must be up setting some thing im going to try and find some 1.5mm 4 core shielded wire over the weeked for that  iv orded that bored and im going to try my home pc friday night just to see what it will do.

Thank you for your in put it nice to just get a bit of help from any wear
Re: homing and limits
« Reply #9 on: October 30, 2009, 05:30:48 PM »
To night iv tyred my home PC in the work shop.  I have got round my switch's tripping now but I'm still having problems with my machine i all so have seen a difference on the dynastic screen there is a lot more green leds on on the right hand side is this good or bad. and it is the vdf for sure that is giving me a lot of problems