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  1. #1
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    Control box electronics question

    I'm going to include a link to a youtube video I made. I was hoping someone might be able to help me out.

    The video contains two clips illustrating two different problems.

    [ame="http://www.youtube.com/watch?v=gAli9uwbFV4"]See video here[/ame]

    In the first part of the video you'll see the machine cut 3 holes. After each cut the machine should raise to safe height and move to the next cut, but on the third hole if you watch close you'll see that the machine only lifts about halfway up to safe height and the Z motor makes this grunting noise and then moves off to the next cut. The trouble is, Mach thinks it made it all the way up to safe height, but it didn't. The DRO may read .75" on Z, but it's actually only at, say, .25" which means when it lowers for the next cut, it will lower the torch the full .57" to pierce height which is now actually .32" below the material surface. If that's on a cut that isn't going to index that's a problem.

    Any thoughts on that? It's really a pain and this thing does it all the time. It's always on Z when it lifts to safe height. It's intermittent so there's no telling where it will do it.

    The second clip is more troubling. It shows the machine moving to safe height after a cut and then heading for the next cut, but halfway there the control box triggers an emergency stop, error trips red and stops the motors, but Mach doesn't get this message. It's bad enough that it triggers the emergency stop to begin with, but the fact that Mach doesn't get the message only compounds the problem. As you can see in the video, Mach thinks everything is still hunky dory and keeps running the program. Even though the motors are stopped and the torch is .75" off the material, Mach still tries to fire the torch and I have to go shut that down. This screws up the tip, first of all, and secondly, the DROs in Mach are all off now and I have no idea where the torch is. I can't simply reset the control box and start everything back up because I've lost my concordance. The tip and that piece of metal are just trashed now.

    Sometimes the control box will do this without anything running at all. Mach's not running a part file, the torch isn't firing, there's no other software installed on the machine, no network cards, no wireless devices, it's a stripped down box with Mach and sheetcam on in and the only thing running is Mach. The control box is on and all the sudden it will just trigger red like you hit the emergency stop button.

    What does that sound like? What component or conflict would most likely be the culprit? I don't know the electronics well enough to know the path information takes. If the torch isn't firing a plasma beam, I don't know what other sources of noise would screw things up with it just sitting there. The motors aren't turning, the torch isn't firing. I dunno. Any thoughts?

    It's been doing this for over a year so all options are on the table. I'll start buying and replacing cards and parts if I have to. I just need to fix it so it's reliable and I don't care how that gets done.

    The table was build by PlasmaRoute CNC out of Ada, Oklahoma and the electronics were supplied by candcnc. Near as I can tell, the control box electronics look like Tom's PlazPack-1A but mine has g203v geckodrives. The plasma cutter itself is a Cutmaster A40.

    Thank you.

  2. #2
    Community Moderator Al_The_Man's Avatar
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    Dec 2003
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    Your Z is most likely loosing steps, either through undersized motor or tight mechanical condition on the Z lift would be my guess.
    The E-Stop problem is a hardware wiring one, you apparently do not have a relay contact for e.g. into Mach that advises that an E-stop has taken place.
    Did you get full schematics with the machine?
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  3. #3
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    Quote Originally Posted by aaronbee View Post
    I'm going to include a link to a youtube video I made. I was hoping someone might be able to help me out.

    The video contains two clips illustrating two different problems.

    See video here

    In the first part of the video you'll see the machine cut 3 holes. After each cut the machine should raise to safe height and move to the next cut, but on the third hole if you watch close you'll see that the machine only lifts about halfway up to safe height and the Z motor makes this grunting noise and then moves off to the next cut. The trouble is, Mach thinks it made it all the way up to safe height, but it didn't. The DRO may read .75" on Z, but it's actually only at, say, .25" which means when it lowers for the next cut, it will lower the torch the full .57" to pierce height which is now actually .32" below the material surface. If that's on a cut that isn't going to index that's a problem.

    Any thoughts on that? It's really a pain and this thing does it all the time. It's always on Z when it lifts to safe height. It's intermittent so there's no telling where it will do it.
    It's probably NOT the lift to safe height. It's all the moves during the Cut from the DTHC. The Z will lose steps as it cuts if the THC Rate % is set too high or if the Z is binding. The cure is easy: Lower that value. It's on the Settings Tab in MACH3. You need to also check the Z of any binding. Take the coupling loose from the motor and rotate the z screw by hand so you can feel the moves. Raise it up from 0 up to about 1". Make sure it does not bind mechanically as it it lifts. Also make sure ALL of the setscrews are tight on all of the couplings and pulleys. The grinding sound is a stepper motor telling you it's hurting (loosing steps from a stall). If it does it when it lifts then it's stalling during the lift and you really need to check the binding aspect. Then if it's clear check the Z velocity and acceleration in MACH motor tuning. You can jog the Z at full speed by pressing the SHIFT key and holding it before you use the jog buttons. I would jog it up and down a bunch of times after setting the zero on the top of a sheet of material and then on measure the final position and see if it agrees with the Z DRO. That will tell you if it's happening in the Z moves or only during when the DTHC is engaged during a cut.
    The second clip is more troubling. It shows the machine moving to safe height after a cut and then heading for the next cut, but halfway there the control box triggers an emergency stop, error trips red and stops the motors, but Mach doesn't get this message.
    Sounds like the EPO Bypass in the MP3000 box is ON. There is a small jumper (J6) that bypasses the E-STOP from the Power Control. The MP3000 is designed to work with other control boxes so the jumper is there to allow it to come out of reset with other controllers that do not have an integrated shutdown (which the Plazpak DOES have). There is a relay in the power controller on your system that does two things: It shuts off the AC (through a larger AC relay) and opens the E-STOP line. It does this anytime there is a power down OR a fault that shuts off power.

    here is what to do:

    1. Go to www.candCNC.com/manuals.htm
    2. Download the MP3000E manual.
    3 While you are there download the DTHC manual
    4. Unplug the PR3000 box (our MP3000)
    5. Open the 3000 box (two screws on the bottom)
    6. Find the section on the option jumpers and J6. Pull the J6 Jumper.
    7. Close the box back up. You should now NOT be able to come out of RESET until the DC power is ON to the motors and it should go into RESET anytime there is no DC to the motors.

    The faulting is usually caused by a power overload. There are status lights (either on the front or inside that will tell you WHY it stopped. It's designed to protect itself and the drives from overload, Overvoltage and even over temp conditions.


    It's bad enough that it triggers the emergency stop to begin with, but the fact that Mach doesn't get the message only compounds the problem. As you can see in the video, Mach thinks everything is still hunky dory and keeps running the program. Even though the motors are stopped and the torch is .75" off the material, Mach still tries to fire the torch and I have to go shut that down. This screws up the tip, first of all, and secondly, the DROs in Mach are all off now and I have no idea where the torch is. I can't simply reset the control box and start everything back up because I've lost my concordance. The tip and that piece of metal are just trashed now.

    Sometimes the control box will do this without anything running at all. Mach's not running a part file, the torch isn't firing, there's no other software installed on the machine, no network cards, no wireless devices, it's a stripped down box with Mach and sheetcam on in and the only thing running is Mach. The control box is on and all the sudden it will just trigger red like you hit the emergency stop button.

    What does that sound like? What component or conflict would most likely be the culprit? I don't know the electronics well enough to know the path information takes. If the torch isn't firing a plasma beam, I don't know what other sources of noise would screw things up with it just sitting there. The motors aren't turning, the torch isn't firing. I dunno. Any thoughts?
    It would help to know what error code you are getting. Unfortunately that blackbox it came in (not our enclosure) is hard to get into to see the status lights on the earlier systems. New ESPII's have the lights on the front panel. If your box has the BRB (Big Red Button) on the end than it has been known to stick and become hair-trigger. It shuts down with no fault. You can pull the red lens (part that moves) and either lube it a little or sand the edges lightly to get rid of any snags. It needs to pop all the way out when released and not stick.


    It's been doing this for over a year so all options are on the table. I'll start buying and replacing cards and parts if I have to. I just need to fix it so it's reliable and I don't care how that gets done.
    We honor our warranty (2 years) on our equipment. Most of what you describe can be fixed with either a jumper, a software setting or in the case of the oversensitive faulting, a special cable. PR should know these answers.

    If you can live without it you can ship it directly back to us to check out. I think if you will fix the Z losing steps (using the THC Rate reduction) and the not stopping on a fault, then you will have most of the problems resolved. If you live close to North Texas (we are between Sherman and Bonham) then you can give us a call and bring the unit down. Phone number is on the website. I take phone calls. We have a full test bench.
    The table was build by PlasmaRoute CNC out of Ada, Oklahoma and the electronics were supplied by candcnc. Near as I can tell, the control box electronics look like Tom's PlazPack-1A but mine has g203v geckodrives. The plasma cutter itself is a Cutmaster A40.
    We just had an A40 in there for evaluation with our new DTHCII electronics. We have an Hypertherm 45 and 85 (and older 1000 G3) as well.

    We did indeed furnish MOST of the unit. Depending on the time frame we may have not furnished the Gecko drives. It's not our motors we supply with the Plazpaks and we did not wire them. The control electronics and the DTHC are ours.

    You don't have to suffer in silence. Join my CandCNCSupport Forum on Yahoo. Guys get answers to questions and problems every day.

    Tom Caudle
    www.CandCNC.com

  4. #4
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    Quote Originally Posted by Torchhead View Post
    Sounds like the EPO Bypass in the MP3000 box is ON. There is a small jumper (J6) that bypasses the E-STOP from the Power Control. ...

    Tom Caudle
    www.CandCNC.com
    J6 jumper is gone! Mach won't budge unless the motors have power. Nice. Thank you.

    I'm going to assume the error code status lights are the 6 LEDs located in the blackbox above the label "PWR FAULT"? If so, the next time it trips I'll make note of which lights flash, blink, twinkle, cycle... or whatever it is they do.

    I rapid jogged the Z motor up and down for about a minute and DRO zero still matched actual zero on the machine. It agreed with the real world, in other words.

    I'll play with more later, but for now I need to actually work. The J6 jumper is exciting all by itself, though.

    Thank you.

  5. #5
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    Quote Originally Posted by Torchhead View Post
    It would help to know what error code you are getting. ....

    Tom Caudle
    www.CandCNC.com
    The control box only stopped once last night, but when it did, two things happened. Because the J6 jumper is gone (and smashed with a hammer), Mach stopped on a dime along with it, which means it DIDN'T ruin the tip like you saw in the video and I was able to reset everything and save the part.

    Secondly, of the 6 LEDs inside the box, reading from left to right, the first LED was flashing red about 2 times a second. Is that a fast flash or a slow flash? And what does that tell you?

    Thanks

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