Shielding wires

LTEPM
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Re: Shielding wires

Post by LTEPM » Tue May 26, 2015 2:02 am

I experienced an issue today when turning the DNP611 on or off, the Z axis lost power and plunged the bit into my workpiece. I moved the router to a different 120VAC circuit than the controller is on and controlled the on/off from a power surge strip, appears to have cleared my issue today.

I have other bugs to figure out now, likely operator error.

rtlflatt
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Re: Shielding wires

Post by rtlflatt » Tue May 26, 2015 3:18 am

LarryGZone wrote:Well, the problem is not shielding related. I have experienced the machine resetting even with the spindle powered off. At random times it happens even just at rest (no job running).
Steppers use most current when they are on and not moving so if they are cause I don't think not moving would prevent this issue
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LTEPM
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Re: Shielding wires

Post by LTEPM » Tue May 26, 2015 3:22 am

I would suggest to check your com port settings prior to running a job, on my laptop with Windows 8.1 the Com Port Speed resets to 9600-8-N-1 not sure what causes it.

rtlflatt
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Re: Shielding wires

Post by rtlflatt » Tue May 26, 2015 3:52 am

weird. do com settings change after rebooting or is it after controller resets?
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LarryGZone
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Re: Shielding wires

Post by LarryGZone » Tue May 26, 2015 12:42 pm

LTEPM wrote:I experienced an issue today when turning the DNP611 on or off, the Z axis lost power and plunged the bit into my workpiece.
I have experienced this same thing as well. I believe the controller board resets, causing this to happen.
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cvoinescu
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Re: Shielding wires

Post by cvoinescu » Tue May 26, 2015 1:06 pm

This is a long-standing problem with USB-connected machines. We've seen it ever since Shapeoko 1. Other machines (for example, 3D printers) can also be affected. The USB conenction is very sensitive to interference; once it drops, it does not restore itself.

There are several things that have been shown to help:
  • Locate the USB cable away from all the other cables (motors, power supply, mains cables);
  • Power the machine and the computer controlling it from the same power strip;
  • Power the machine from a circuit without noisy loads. Particularly bad are refrigerators and air-conditioning units*, but anything with an electric motor can be a problem too (spindle, vacuum cleaner). Try to plug the spindle in a different outlet -- on a different circuit, if you can.
  • Use a short, well-built, properly shielded USB cable with ferrite cores.
  • Connect the frame of the machine to ground/earth (this may make the problem worse, though). Connect ground of computer and machine together.
  • Use galvanic isolation, either on USB, or between the USB-to-serial converter and the rest of the controller. Or, replace USB communication with something wireless, for example Bluetooth.
Unfortunately, the latter is the only one that seems to eliminate the drops completely, but USB galvanic isolation is expensive, and intervening on the serial communication is not easy to do with the Carbide Motion controller. Everything else helps, though, so it's worth trying, just in case it's enough to solve your particular case of interference.

* Seemingly random drops are often a compressor turning off somewhere else in the house.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

LarryGZone
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Re: Shielding wires

Post by LarryGZone » Tue May 26, 2015 1:16 pm

cvoinescu wrote:This is a long-standing problem with USB-connected machines. We've seen it ever since Shapeoko 1. Other machines (for example, 3D printers) can also be affected. The USB conenction is very sensitive to interference; once it drops, it does not restore itself.

There are several things that have been shown to help:
  • Locate the USB cable away from all the other cables (motors, power supply, mains cables);
  • Or, replace USB communication with something wireless, for example Bluetooth.[/*]
Unfortunately, the latter is the only one that seems to eliminate the drops completely, but USB galvanic isolation is expensive, and intervening on the serial communication is not easy to do with the Carbide Motion controller. Everything else helps, though, so it's worth trying, just in case it's enough to solve your particular case of interference.
Thanks cvoinescu. Do you have a recommendation for a bluetooth module?
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cvoinescu
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Re: Shielding wires

Post by cvoinescu » Fri May 29, 2015 2:19 pm

The cheap modules from China work fine. Or you can get a quality product from, say, SparkFun.

I should mention I do not have a Carbide Motion board yet, and I don't know whether the pins you need are broken out, or you need to solder directly to the board.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

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