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Author Topic: Stepper rough and intermitant operation  (Read 2876 times)

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Offline bowber

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Stepper rough and intermitant operation
« on: September 25, 2008, 10:02:46 AM »
Hi all

Well the gremlins have struck, I have a 4th axis that I made and is normally disconnected from it's driver when not in use.
I fitted it back on my mill last night to setup a job and just had to jog it round, nothing happened at first no noise no movement so i tried the other way and it moved slowly and very roughly and then stopped.
I checked for smooth movement of the stepper and axis by hand and it was all free and smooth, I then turned the power back on and it locked the stepper but just the same when jogging.
I have tried to input G0 and G1 moves in the manual input area, still the same.

So far I've checked the cable connections from the breakout board to the driver, I unscrewed them and checked then re fitted.
Checked the power to the driver.
Checked the pin settings in Mach and on the breakout board.
Checked the motor tuning, no change from before.
I've also disconnected the coupling and tried the stepper on it's own but no difference.

This is all strange as it was working  when it was removed and I haven't even used the mill much since and I'm certain I've not changed any settings.

The only thing I've yet to check is that the wires into the plug are ok, I have a socket on the front of the control box that takes this plug.
I'm wondering if having the mill running without a stepper attached to the 4th driver has damaged it, has anyone else had this.
It's a 3A driver from Arc Eurotrade set at 2.5A and the stepper is from them as well.

I have a new stepper (bigger but it should do to check the driver) so I can try that but I'll have to order a new driver to check that and it's money wasted if it turns out to be ok.
I don't want to go through the hassle of using one of my other drivers as they need resetting for the Amps and are a pain to get to.

Does anyone have any suggestions to try before I buy a new driver? I'll try another set of pinouts tonight just to make sure.

Thanks
Steve

Offline Bodini

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Re: Stepper rough and intermitant operation
« Reply #1 on: September 25, 2008, 12:46:10 PM »
I'm sure this is of no help, but you jogged my memory.  My 4th axis was acting goofy one day after a restart.  I have no idea what happened, but the 'step pulse' or 'dir pulse' got set to something wrong (both normally set to 0)... and I swear I didnt change it.  Anyway, its an easy check for you.

-Nick

Offline Hood

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Re: Stepper rough and intermitant operation
« Reply #2 on: September 25, 2008, 04:19:43 PM »
Checked to see if the port is putting out the direction pulse? Use a voltmeter between the Dir pin and a ground pin and see if the voltage goes 0 to 5v when reversing directions. Similar with the Step pin but you will see a low voltage (faster jog equals higher voltage seen)

Hood
Re: Stepper rough and intermitant operation
« Reply #3 on: September 25, 2008, 07:53:03 PM »
You might switch the motors with one of the other drives temporarily....to verify where the problem lies.
RC

Offline bowber

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Re: Stepper rough and intermitant operation
« Reply #4 on: September 26, 2008, 04:59:35 AM »
Thanks for the ideas.
I was going to try altering to another set of pins last night but my wife invited some friends round so I didn't get chance to go into the workshop, and tonight we're going out to a local music night.
It's a hard life :D
Think I'll finish early today, as I'm self employed, and have a fiddle with it all. I'll let you know the results.

Just thought Nick you may be right, when I checked the motor tuning I remember they were 0 & 5 in that order, is this normal or should it be 0 & 0?
I'll check against the other Axis (what's the plural for Axis ;D)

Steve

Offline bowber

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Re: Stepper rough and intermitant operation
« Reply #5 on: September 26, 2008, 05:24:45 AM »
Well I have looked at it and I think that must have been enough because without doing anything else the 4th axis is working as it should ???
I really hate that sort of fix because I've no idea what's changed.
I'd have suspected the computer or power supply if all the axis were rough but the rest were fine.

Ah well I guess I best be happy that it's working.

Thanks for your input.

steve