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Author Topic: Home all axes doesn't work, but each works individually  (Read 1167 times)

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Home all axes doesn't work, but each works individually
« on: March 31, 2017, 12:02:08 AM »
Hi Everyone,
     I'm just getting started using Mach 4, and this is the first CNC machine that I've used, so please be patient with me if I'm missing something or stating the obvious. I retrofitted an Emco PCMill55 CNC mill by making my own interface board between the existing electronics and an Ethernet SmoothStepper (here are some photos / short videos, if you're interested: https://goo.gl/photos/thdMzhiHWhm6BxYF8 ). Everything is (sometimes) working ok, but I have a few recurring problems that I'm having trouble tracking down. The first is difficulty homing all axes, and the second is the program freezing at the G-Code line which sends the machine to home at the beginning of the program. I have a feeling that they are related, so I'll focus on the first and start a separate thread for the second later if it isn't.
      This machine has home switches for each axis, rather than limit switches at the end of the travel, so it should trigger the home switch, then back off in the opposite direction until the home switch turns off. That's exactly what it does when I go into the diagnostics tab and tell it to reference X, Y, or Z individually. Each of them works fine on their own. However, if I tell it to reference all axes, it moves Z up (which is set to the first in the order), until it hits the home switch, lights up the indicator showing that the home switch is on, displays a message in the lower left hand corner that the home switch has been triggered, and then ceases to do anything else at all. It just sits there, not moving in any way, and as far as I can tell, it would never move on its own after that, unless I manually stop it. I've tried changing the axis order around, but that doesn't make a difference. I've turned logging on before telling it to home all axes, and there isn't anything interesting there either as far as I can tell. I've waited forever with the hopes that something might time out and give a debug message, but no luck there so far either.
       So I have a few questions:
            - Has anyone else experienced this, and if so, how did you fix it? I came across an old thread that seemed somewhat similar, but it didn't have any details on fixing it.
            - Where should I start with troubleshooting this? Is there any way to get more detailed diagnostics than the standard logging?
            - Is it a problem that I'm using the wx4 screen which has 4 axes, even though I'm only using 3? Could that be the source of the problem? The A axis isn't set to home, so it didn't seem like the problem, but I thought I'd ask.

Thanks for any advice / help!

Offline Chaoticone

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Re: Home all axes doesn't work, but each works individually
« Reply #1 on: March 31, 2017, 08:34:29 AM »
Try configuring your switches to only be home switches, not limits too. If there are no limit switches enabled you will not get a limit switch error. Sounds like you might be fighting a noise issue. Might want to see if you can filter those home switch inputs in the ESS config.   
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Re: Home all axes doesn't work, but each works individually
« Reply #2 on: March 31, 2017, 08:54:17 AM »
Thanks for the reply!
    I don't believe the home switches are set up as limit switches. I didn't intend to set them up as limits, and I can jog past them with no problems. I'll double check my configuration when I get to work this morning, but I'm 99% sure they are just set to home switches.
Re: Home all axes doesn't work, but each works individually
« Reply #3 on: March 31, 2017, 01:19:41 PM »
Hey, just a quick update: I verified that the home switches were not set as limit switches, and I also checked to make sure that the soft limits weren't causing any problems (they weren't, it behaved the same with the soft limits enabled and disabled, and it never reached those points). 
    I also found that the second problem that I was describing (where it wouldn't run a program, it would get hung up on the go to home command) was entirely unrelated. I had a door switch set to motion-inhibit, and I had the polarity reversed, so it refused to run with the door closed.
    Any other ideas? I'll keep this updated if I get any more diagnostic information.