Hello Guest it is October 16, 2019, 04:13:29 AM

Author Topic: Limit Switches go crazy  (Read 5233 times)

0 Members and 1 Guest are viewing this topic.

ryanpb

*
Limit Switches go crazy
« on: May 31, 2006, 08:56:38 PM »
Any suggestions?

When I enable the limit switches they fault out for no reason in Mach 2.
When I enable the limit switches they go crazy no reason in Mach 3.
I have had the debounce set as high as 10,000 in both boxes.  They will still fault out in about 5 to 10 minutes.
I have optimised the computer and everything.
By the way in other post it states (and the Mach 2 pdf) to adjust the debounce but does not give a defintion for index.
This is the only issue I have before having a complete setup.

Any help?
Re: Limit Switches go crazy
« Reply #1 on: May 31, 2006, 09:47:01 PM »
Take the wires out of the box or cable tray.. if you have the limit switch wires 1 foot from all the other wires do you have the same problem?
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

ryanpb

*
Re: Limit Switches go crazy
« Reply #2 on: May 31, 2006, 09:55:40 PM »
Thanks Brian!

That could be the problem and will try that but I have the type shielded wire ruining to all the other components in roughly the same proximity with out any problems such as encoder wires.  I have even grounded the shield to the breakout board.  I will look and see if maybe the limit wires come closer to the motor wires some place.

Thanks Ryan

ryanpb

*
Re: Limit Switches go crazy
« Reply #3 on: May 31, 2006, 10:06:23 PM »
I have tried everything.  I am using the second parallel port with a pci slot card set with no interrupts.  Could the port be interrupted?  Maybe the problem could be the breakout board (cnc4pc)?  Maybe it this not sinking enough voltage to stay in a constant state.  Is that likely?  I have grounded the shielding out  the breakout board.  I have used the same type cable to all the other components and they run fine.  I have encoder cables run in roughly the same distance from the motor wires.  I have relays working off the second breakout board and they run fine.
 
It could be noise but I don't see how.
It is happening to all the limit switches.  individually or all together.
 
I have 12 volts running though the coil of a relay in series with normally closed limit and home switches.  When the switch breaks it opens the relay  and opens the other side of the relay which is contected to the breakout board from the pin the the ground.   With the active low setting on the limit switch this should work right?
Re: Limit Switches go crazy
« Reply #4 on: June 01, 2006, 02:17:15 AM »
Ryan,  why are you using relays for limit switches?  Are these Solid STate Relays per chance?  If so, becuase of the way SS Relays are designed they will not give you continuity and therefore will not trigger or create exactly the type of results you describe.

Sid

ryanpb

*
Re: Limit Switches go crazy
« Reply #5 on: June 01, 2006, 02:46:16 PM »
Sid,

They are not solid state relays, they are standard relays.

The reason for the relays is to send 12 volts around the limit switch circuit without stealing to much of the 5 volts low amp from the breakout board.

I am running 12 volts around the limit switches and coming from the breakout board with the 5 volts across the relay contacts back to the breakout board.

Thank RYAN
Re: Limit Switches go crazy
« Reply #6 on: June 01, 2006, 05:38:43 PM »
Dude,

I could be wrong but Voltage through the limit switch circuit doesn't sound right to me.  I just metered my machine and I have 0v runing through that circuit.  I have always thought that the limit switch circuit was a simple Ground continuity circuit.  Maybe this is just the way my driver board works but, based on what you describe, I'm thinking that you problem relates back to the fact that you are sending DC voltage where the board only expects to see continuity to ground.

I would suggest going back a few steps and try testing with just 2 wires connected to your driver board.  In Mach3 there is a diagnostics page and you can see when you have contact (or no contact) assuming that you have the switches configured correctly in the ports and pins config section.

Touching the wires together should light up an LED on the Diags screen.  Once you get this far, then I think it will be easy to Suss out the weirdness with the switches.

HTH

Regards,
Sid
Re: Limit Switches go crazy
« Reply #7 on: June 01, 2006, 06:15:47 PM »
Check to see that your voltage out of your parallel port is 5V and NOT 3.8V. This is a problem with the newer computers...
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

ryanpb

*
Re: Limit Switches go crazy
« Reply #8 on: June 01, 2006, 11:14:47 PM »
Fact of the matter is as posted earlier in the post I was using pin to ground and the switch were going crazy.  Now I am at pin to 5 volts from the breakout board (cnc4pc) and the limit switches are just going "nuts" I'll say.  However you may be right.  I may burn out the opto in time.

5 volt or 3.8 volts out of the parallel port shouldn't matter because it is hooked up to a breakout broad or should it?

The thing now is that when I have the Y and or the Z axis switches enabled and I go to move the Z axis the limit LED's light up for no reason.

I am using a second parallel port which is a pci slot card to the breakout board with the 2 to 9 pins set as input.  I have the SS relays hooked up as outputs for the spindle etc and they work fine. 

I am at a lose.  I have tried everything.

Any work around?
THANKS  RYAN
Re: Limit Switches go crazy
« Reply #9 on: June 02, 2006, 12:02:25 AM »
Ryan,

Not being familiar with your breakout board, I just went to the cnc4pc website and discovered they have different models.  Which do you have?  I looked at a couple of models that they offer and I'll say it again- Based on the diagrams CNC4pc shows at their site, IMHO you should not be sending ANY voltage to the limit/home switch circuit.

Me thinks that in doing so, something may be tweaked.  Maybe not, did you do the wire test I previously described? And yes, BTW- 3.5-5v Will make a diff, so maybe you wanna put a meter on that too.

Sid