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Author Topic: Table crashed now motor runs full speed. What to troubleshoot next?  (Read 1501 times)

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The table crashed. I think it might have been what caused the issue. Anyway now the X axis motor runs full speed ahead. The Y table moves just fine, but X rapids absolutely insanely fast and does not stop if i let go of jog. Even a single "step" and it takes off.

I've made sure I was in inches units, I double checked and changed acceleration and velocity settings and tried turning them down. It works but it still wont stop and eventually speeds up to same speed before I hit reset.

I've power cycled everything, the "DRO" is receiving feedback from the encoder on the motor so I don't think that's it I have no idea what to check next. Feedback on both of them is funny though it steps through "thousandths" instead of inches even though the steps per unit is correct and just worked the other day. The only think I can think of is it is a bad interface card?

Any help would be appreciated. Running mach3 demo, with a Galil 1820 driver and brushed servo motors.
Re: Table crashed now motor runs full speed. What to troubleshoot next?
« Reply #1 on: June 27, 2016, 02:35:07 PM »
Swap the inputs to the drives and see if the error stays with Mach3 Axis or driver hardware

Offline mc

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Re: Table crashed now motor runs full speed. What to troubleshoot next?
« Reply #2 on: June 27, 2016, 04:37:21 PM »
Are you sure the DRO is getting feedback from the encoder?
Unless the DROs have been specifically setup to use encoder inputs, they only show the commanded position.

What you're describing sounds like a typical encoder fault. The drive commands a move, but doesn't see one, so gradually keeps increasing the output leading to the motor running away. One way to test, would be to disconnect the motor from the machine, enable the drive, and try turning the motor shaft by hand.
 If the drive/encoder is working correctly, then the shaft should be locked in placed, and spring back into position once you release it. If it doesn't return, or it starts moving as soon as you enable the drive, then there is a problem with the drive/encoder/wiring.
Re: Table crashed now motor runs full speed. What to troubleshoot next?
« Reply #3 on: June 27, 2016, 04:59:29 PM »
I swapped the inputs and magicniner suggested, and now both the motors move when I command a jog, and at full speed.

I also tried reinstalling Mach3 along with the plugins.

Before it was just the X axis that freaked out, but now that I swapped all the connections to the opposite motor they both freak out at the same time.

The galil motion controller, along with the motors, and drivers are all brand new but have been sitting around for nearly 20 years so its not like they have lots of hours on them.

Any ideas from here?

Offline mc

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Re: Table crashed now motor runs full speed. What to troubleshoot next?
« Reply #4 on: June 28, 2016, 04:05:47 PM »
Unfortunately Galil systems aren't that common, and from the quick scan of the old product info page, it could be set up a few different ways.

You need to break things down into sections that you can troubleshoot.
I'd be looking at the following areas.

Encoders.
Are they working?
Do you have a scope so you can check they are producing the correct signal?
Is that signal getting back to where it needs to (i.e. the Drive or Controller)?

Drives.
How are they controlled? Step/dir or 0-10V?
If analogue, a quick check is to get a low voltage source (1.5V battery is ideal for a basic test) with a 1k resistor connected in series, and with the drive analogue input wires disconnected and the driver powered/enabled, connect the battery/resistor across the analogue input terminals. The motor should spin reasonably slowly. Then try connecting the battery/resistor the opposite way, and make sure the motor turns at a similar speed in the opposite direction.
Re: Table crashed now motor runs full speed. What to troubleshoot next?
« Reply #5 on: June 29, 2016, 12:21:36 PM »
Unfortunately Galil systems aren't that common, and from the quick scan of the old product info page, it could be set up a few different ways.

You need to break things down into sections that you can troubleshoot.
I'd be looking at the following areas.

Encoders.
Are they working?
Do you have a scope so you can check they are producing the correct signal?
Is that signal getting back to where it needs to (i.e. the Drive or Controller)?

Drives.
How are they controlled? Step/dir or 0-10V?
If analogue, a quick check is to get a low voltage source (1.5V battery is ideal for a basic test) with a 1k resistor connected in series, and with the drive analogue input wires disconnected and the driver powered/enabled, connect the battery/resistor across the analogue input terminals. The motor should spin reasonably slowly. Then try connecting the battery/resistor the opposite way, and make sure the motor turns at a similar speed in the opposite direction.

I narrowed it down to the encoders on the one axis. I pulled them both apart one by one and scoped the outputs. The axis gives absolutely nothing back when turning it, and I double checked the cable by swapping the motor plugs and verified I got the good axis encoder feedback.

Thanks for the help. I got the other axis going. I think there were a couple problems going on -- somehow in the reinstall the settings got switched back to steppert for the one servo so it just wouldn't stop. I changed it back to servo and the good axis is going again, but the other axis is still dead so I need to figure out how to replace that encoder.

Thanks again!