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Stepper motors screaming

Added by darrenp about 12 years ago

Hi,

Ok, I'm getting stuck with this now. I've got the board built, loaded the test firmware and all the endstops, etc work fine (Just going to build the LCD tonight), but when I put the real firmware (14th September build) and turn it on, I get a couple of clunks from the steppers, then a high pitch scream after a few seconds as it tries to home the head. It actually sounds like a piezo buzzer going off, but I'm pretty sure there isn't one in the machine, and its coming from the steppers.

I've adjusted the pololu drivers through pretty much the whole range of the trim pots, with no change. I've adjusted the microstepping (Tried x16, x8, and none) which doesn't do anything either. I've also tried some other driver boards but no change.

Am I missing something? Any pointers for what to try next?

I've put the original chinese board back in to make sure it all works, and it does, so I've not melted a stepper or anything similar.

Thanks,

Darren.


Replies (10)

RE: Stepper motors screaming - Added by pieterb about 12 years ago

Maybe your stepper motors on your machine are wired different then one in the HPC LS3020 ?
That would explain the noise http://hmin.tripod.com/als/fsmyth/pages/stepdrv5.html

RE: Stepper motors screaming - Added by darrenp about 12 years ago

Yeah, I thought that too, but just double checked the continuity on the coils, and pins 1&2 are one coil, 3&4 are another, and all looks like its wired up correct. :/

RE: Stepper motors screaming - Added by jaap about 12 years ago

The stepper drivers have a regulator on them. If your stepper motors make noise, you probably have to turn down the power on the stepper driver.

RE: Stepper motors screaming - Added by darrenp about 12 years ago

Hey,

Unfortunately I've tried that too. I've adjusted it the full range, from min to (almost) max. No change in the screaming noise. The steppers don't move at all either. :(

RE: Stepper motors screaming - Added by jaap about 12 years ago

Maybe the frequency is totally off for these steppers? Try it on a much lower frequency?

And did you try swapping just two wires (1&2) of the stepper to change the direction of one coil?

RE: Stepper motors screaming - Added by darrenp about 12 years ago

Cool, thanks.

I'll try swapping the wires shortly. How do I change the frequency?

Darren.

RE: Stepper motors screaming - Added by jaap about 12 years ago

The test code can do 500Hz(f) or 10Khz steps (F). You can change them by changing line 185/187 of main.cpp in the source code (attached). This source code can be compiled with the online MBED compiler.

laos_iotest_board.zip (49.9 KB) laos_iotest_board.zip

RE: Stepper motors screaming - Added by darrenp about 12 years ago

Ok, I'm confused now (tho thats fairly normal)

If I leave the head parked at the Y endstops and boot up the real firmware, it boots fine, and the X homes ok. If I send a simple print from visicut, the axis move as they should (needs a lot of tweaking of the config file, but one step at once!). But still, if it tries to home the Y axis on boot, thats when I get the screaming from the stepper.

Getting there! :)

RE: Stepper motors screaming - Added by jaap about 12 years ago

So, what did you fix on the X stepper? You should probably do the same on the Y stepper?

X-speed and Y-speed do not necessarily match, you might still be a factor 2 or 4 off...

Another possible test: swap X and Y connectors, see what happens?

RE: Stepper motors screaming - Added by darrenp about 12 years ago

Actually, it turned out to be a config parameter. Not entirely sure which one did it in the end unfortunately, I was trying all sorts. It isn't helping that the Y axis seems to be inverted. Homes to the correct place, but when trying visicut it moves to the y max first before cutting. I'm pretty sure thats down to config settings.

Anyway, it is working now and just hooked the laser up to be controlled by the board and that works too. PWM and tuning the settings next.

I'll post a working config.txt for this printer on the wiki page I made for it.

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