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Delta printer motor control

Posted by cheddy 
Delta printer motor control
November 12, 2017 09:31AM
I have a new reprap delta printer that I just built from scratch, using RAMPS 1.4/Arduino Mega 2650 controller with Repetier-Firmware. I am having a lot of trouble getting the motor controls to work properly. I have tested all 3 max-endstop switches and M119 reports the correct states. When I manually lower the accessor @ 100mm and then hit the home button (Repetier-Host) the Y-tower and the Z-tower sliders shoot to the top, while the X-tower slider doesn't move. The Y and Z motors continue to run even though the endstops are triggered. When I try to move the accessor using manual commands the X-tower responds, but the Y and Z towers do not. This happens regardless of the direction I am attempting to move it in (i.e. moving in Y direction or in X direction - only the X motor moves.) I have been reading some of the guides for configuring repetier-firmware for delta printers and as far as I can tell the configuration is correct, but obviously something is seriously wrong.
As I see it there are two problems with the above (at least):
1. Uncoordinated motor movement
2. Failure of endstop trigger to stop motors

I realize that the above description is pretty vague, but I'm not sure how better to describe it or where to go from here with troubleshooting.
If anyone has some pointers I would greatly appreciate it.

Thanks,
Cheddy

Edited 1 time(s). Last edit at 11/12/2017 09:32AM by cheddy.
Re: Delta printer motor control
November 12, 2017 12:14PM
I'm wondering whether you have the right tower connected to the correct stepper port, so that motors don't match to end-stops?

It would be helpful if you attached your Configuration.h file to this thread.
Re: Delta printer motor control
November 12, 2017 02:07PM
Sorry, should have thought of that. My configuration.h is attached.

P.S. I'll double check the wiring. I was pretty careful to label them so I knew which was which but I'll check it to make sure.

Edited 1 time(s). Last edit at 11/12/2017 02:09PM by cheddy.
Attachments:
open | download - Configuration.h (32.3 KB)
Re: Delta printer motor control
November 12, 2017 03:53PM
BTW, the wiring on my stepper motors seems different to all the examples i have seen. Mine are wired into into the connector in blue-red-green-black sequence (as delivered), whereas all the examples I have seen are red-blue-green-black. Could this make a difference?
Re: Delta printer motor control
November 13, 2017 12:57AM
The colour of wires on motors is generally not to be trusted. For each motor use a multimeter to measure the resistance between the wires. There are 2 pairs of connected wires in each 4 wire motor cable. Wire them so that one pair occupies pins 1 and 2, and one pair occupies pins 3 and 4. Then change the direction the plug is inserted into the controller if the motor turns the wrong way.

If all the motors are the same brand then they should all have the same wiring. Make sure X tower motor and endstop is the front left tower, Y is front right and z is rear.

Edited 2 time(s). Last edit at 11/13/2017 01:02AM by DjDemonD.

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Re: Delta printer motor control
November 13, 2017 04:18AM
I checked the motor wiring and they are wired correctly (i.e. for the X, Y and Z towers) and from the M119 results when I manually test the endstops I can tell that they are paired correctly, so I am at a loss with this one. I will check the motor wiring to make sure the wires are paired correctly..
Re: Delta printer motor control
November 13, 2017 02:10PM
Update: I tried using Marlin instead of Repetier-Firmware with much better luck. My motors now work more or less as expected, although I had to switch the motor direction. I need to do some more tweaking of the parameters, but it looks like I'm making some real progress at last . I would love to know why the rep-fw was such a dud. All the comments I see claim it is much better than Marlin. However, Marlin is working for me so far, so the old adage 'if it works don't fix it' rings true here.
Thanks for all the advice.
Re: Delta printer motor control
November 13, 2017 03:01PM
I compared your Repetier Configuration.h with what works on my machine. I have a Zonestar ZRIB controller rather than RAMPS, so some differences are expected. But I notice that you seem to be inverting X,Y, Z direction and endstops whereas I don't.

I've attached my Configuration.h for you to look at.
Attachments:
open | download - Configuration.h (32.5 KB)
Re: Delta printer motor control
November 13, 2017 11:44PM
Quote
cheddy
Update: I tried using Marlin instead of Repetier-Firmware with much better luck. My motors now work more or less as expected, although I had to switch the motor direction. I need to do some more tweaking of the parameters, but it looks like I'm making some real progress at last . I would love to know why the rep-fw was such a dud. All the comments I see claim it is much better than Marlin. However, Marlin is working for me so far, so the old adage 'if it works don't fix it' rings true here.
Thanks for all the advice.

The difference, why Repetier seems better than Marlin ( for Deltas ) is Marlins bad stuttering problem, when printing fast curves. 8bit is on the edge, when it comes to Delta kinematics and refreshing a graphic LCD..
Re: Delta printer motor control
November 14, 2017 01:58AM
Quote
cheddy
.... All the comments I see claim it is much better than Marlin. However, Marlin is working for me so far, so the old adage 'if it works don't fix it' rings true here.
Thanks for all the advice.


Your experience is the same I had. Had a working Marlin, tried Repetier, because of all those comments. Gave up after nearly 4 weeks without beeing able to get repetier behave like needed.
Just did another Marlin-Update yesterday on one of my printers - Version 1.1.6, enabled Filament Runout Sensor, Filament Change feature and Advanced Parking - now changing Filament Mid-Print, Pausing or inserting something mid-print is really easy.
Will check some prints, and upgrade my 2nd printer too, if everything works like expected.

I never did notice any stuttering problem with marlin (and both of my printers are deltas) - but may be related to not using graphical LCD. still using 2004 with rotary encoder. - Delta Segments per Second set to 160.
Until now I do not see any need upgrading to any graphical display.
Re: Delta printer motor control
November 14, 2017 02:06AM
Later marlin versions have changed the way they update the graphical displays to update less frequently when printing is intensive and the processor is busy. This gets rid of the stuttering but makes the display less responsive.

To be fair my understanding is that Repetier is coded more optimally and gets more out of the 8bit board, so in theory works better for deltas. But whilst I have tried it a few times, I can never really get the hang of it like I can with Marlin.

I run a delta with 1/32 microstepping from a ramps/mega running RC's marlin/latest marlin (I chop and change). It works fine, but I don't ask it to print at high speed.

If you want a high speed (and accurate) delta then you need 32 bit like Duet, this is my other machine and it would not be possible to do this with an 8bit board:
[youtu.be]


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