Need serious help. Runaway axis on power up.


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    Default Need serious help. Runaway axis on power up.

    I am running Centipede with Mach3, Granite VSD-e servos. Twice on power up, I have had runaway axis. Please tell me how to fix this. Everything is plugged in to a power chord. The servos have HV Power when I plug it in, while I am not booted to Mach3. The Estop is engaged, but evidently has no effect until Mach3 is booted, is that true? Shouldn't I power up the computer, then boot Mach3, then plug in the HV power for the servos? Or have three relays to engage the servos, this is a dangerous situation. Please help. Bob.

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    Community Moderator Jim Dawson's Avatar
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    Default Re: Need serious help. Runaway axis on power up.

    I would certainly expect the servos to be electrically powered down on E stop, no matter what the computer state is. Sounds like your relay idea is correct.

    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Need serious help. Runaway axis on power up.

    When I posed the question to KSI labs, when I was first building the machine, I didn't get a solid answer from Sergey, so I was under the impression that Estop was Estop, well that is not the case. On my Anilam, Bridgeport, everything is booted up and then the servos are engaged through a relay. I will have to create this circuit and will probably solve my problem. With the present system, I think that the estop on Mach3 only opens the signal circuit, not the HV circuit. Thanks, I will pursue the relay circuit. How do most guys set their homemade routers up? Bob.



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    Default Re: Need serious help. Runaway axis on power up.

    One method is to have your estop circuit run through a safety relay, and include the charge pump in the circuit as well. The power for your servo drives should run through a contactor, with the safety relay controlling the coil of the contactor.
    This way, you can't power the servo drives while it's in E stop, and until Mach3 is running, and outputting the charge pump signal.

    The Servos should NOT have power applied when Mach3 is not running.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

    JointCAM - CNC Dovetails & Box Joints
    [URL]http://www.g-forcecnc.com/jointcam.html[/URL]

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


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    Default Re: Need serious help. Runaway axis on power up.

    Thank you, but understand I am a newbie. So, charge pump? I understand circuits if I have a diagram. Any suggestions as to where I could find a simple circuit for the HV estop? Thanks. Bob.



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    Default Re: Need serious help. Runaway axis on power up.

    OK, I went out and powered up everything but the HV power supply. I am trying to picture what would happen if I had an Estop circuit through a relay. I was able to jog with no issues. So everything seems to be OK. Then I unplugged the power supply and observed the blue lights on the drives and the blue lights stayed on because the caps were still charged even though power was cut. So, the way I see it is the relay would have to be installed on the HV 144DC side to cut all power to the drives. If I installed the relay on the 115vac side, the drives would still have HV until the caps were discharged. Is my thinking correct? So, for the servo power to be cut immediately and stop movement, in case of a runaway the relay would have to be on the 144VDC power side. I know from working with the 144VDC that it takes about 20 minutes to go to 0. Even with Mach3 booted and when an Estop is inacted, the only reason it stops is because of the signal and not the HV, as it is still on. Am I correct? Please any input will be greatly appreciated. Thanks ahead, Bob.



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    Default Re: Need serious help. Runaway axis on power up.

    Mor the most part I think you're safe cutting power to the 115V side of the servo power. It takes a only fraction of a second to discharge the caps if it is actually driving the motor. This is the way your Anilam control is wired, it has a solid state relay that energizes the servo power supply. You could also wire in the E stop to break the servo enable signal.

    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Need serious help. Runaway axis on power up.

    See, that's why I am on CNC zone. OK, everything makes sense, but isn't the already opened with the estop on Mach3 when pushed? It's probably something else that I don't understand. Since the runaway, I now plug everything in but the HV power supply and when booted to Mach3, plug it in. Will I be safer doing that, still doesn't cut HV power with estop until I unplug it. Better just wire a relay into 115vac circuit, and it wouldn't matter if it still got a data signal, no power, no movement, I think. I sure thank you for your input. I flew helicopters in Nam and was never as apprehensive over there as I am with this machine. I guess I had control of the helicopter, but don't with this machine, it acts crazy. Hasn't ran away yet by plugging in the HV power after Mach3 boot, so maybe I am OK, I don't know. Thanks again for your help, I will keep you posted. Bob.



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    Default Re: Need serious help. Runaway axis on power up.

    One more thing, what relay should I use? Bob.



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    Default Re: Need serious help. Runaway axis on power up.

    I'm a real fan of the PRD style power relays. I like to hear the solid ''clunk'' when they pull in.

    An example:
    https://www.automationdirect.com/adc...AD-PR40-2A-24D

    You can find these on Ebay and many other vendors also, just match the coil voltage to your system.

    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Need serious help. Runaway axis on power up.

    Thank you, what is the coil voltage of my system, 115vac, or signal voltage, like 10vdc?, Bob.



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    Default Re: Need serious help. Runaway axis on power up.

    OK iget it, the control voltage to operate the relay. I don't have 24 volts, I have a power supply that is 10 to 12 vdc, if they make one like that. Bob.



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    Default Re: Need serious help. Runaway axis on power up.

    They do make a 12VDC coil relay, all common voltages are available. A better way might to be to build a proper E stop circuit outside of the system, by adding another set of contacts to the E stop switch and keeping the two systems completely separate. The original will do whatever it is doing, then the additional contact would actually kill power to the drive power. That way you could use 115V to energize the relay.

    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Need serious help. Runaway axis on power up.

    What type of control-relay circuit is one push button switch, push it once and 115vac come on and push it again and it goes off. I could mount it side by side and then If I had to hit them both. Another words leave the Estop as it is, but be able to disconnect the HV by pushing a button. I am asking, because I have never installed a relay type circuit. I think that when I buy the switch setup there will be a wiring diagram, Thanks Bob.



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    Default Re: Need serious help. Runaway axis on power up.

    I understand it can be a little overwhelming trying to wire up a system the first time. But in reality, it's just like wiring up a light switch, where instead of the light bulb, you have a relay coil. For a commercial or industrial application I would add another relay and require another button push to energize the power. For home shop use, this will work.

    Turn the switch on (twist and pull out), the relay coil energizes, turn the switch off (push in) the relay coil de-energizes.

    If your E stop switch is not identifiable, then the best way would be to buy one that is known, and you are able to get contact blocks (the actual switching part) for. It is possible that your existing E stop switch already has two separate contact blocks, and that one of them is not being used at all. You would have to look and maybe post a picture or two.

    https://www.automationdirect.com/adc...inated/GCX1131

    https://www.automationdirect.com/adc...ocks/ECX1030-2

    One contact block would be wired as original, the other would go to the relay, two completely separate control circuits controlled by one switch.

    If you don't feel comfortable doing this, then please get some qualified help before proceeding.

    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Need serious help. Runaway axis on power up.

    I want to leave the Red estop switch like it is. Beside it maybe one just like it for the HV. Would it even require a relay? Yes, feel OK wiring, as long as I have a schematic, after all I wired the whole machine. I just haven't any experience with a coiled relay. Never needed one. Bob.



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    Default Re: Need serious help. Runaway axis on power up.

    OK

    If the the new E stop switch will handle the power (current) of the servo power supply, then no, you wouldn't need a relay. But the problem is that most of them won't handle that much current. There are some E stop switches that are designed to handle motor loads, so those would work.

    Here is an example
    https://www.homedepot.com/p/POWERTEC...hoCSCcQAvD_BwE

    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Need serious help. Runaway axis on power up.

    Now we are talkin. Here is one rated at 35 amps, overkill but will work. I will try to get a picture of it here. Thanks, you have made my day. Bob.Need serious help. Runaway axis on power up.-powertec-specialty-power-tool-accessories-71008-64_1000-a



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    Default Re: Need serious help. Runaway axis on power up.

    OK, thanks for all of your help. So far, I have had no runaways since I make sure that I am into Mach3 page before I plug in the HV supply, I hope that solved the problem, so a switch will be installed, thanks again, Robert Brown.



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    Community Moderator Jim Dawson's Avatar
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    Default Re: Need serious help. Runaway axis on power up.

    It's always a pleasure to help out where we can. Happy to hear you have it under control.

    Jim Dawson
    Sandy, Oregon, USA


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Need serious help. Runaway axis on power up.

Need serious help. Runaway axis on power up.