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Help adjusting the microstepping settings

Posted by icefire 
Help adjusting the microstepping settings
March 15, 2016 09:23AM
So I've been having some backlash trouble and also found out that the printer axes struggle to move smoothly when printing circles. So I wanted to switch from 1/32 microstepping to 1/16 in order to check if the 8-bit Arduino is overwhelmed by the heavy calculations at 1/32 microstepping with repetier FW (Machine is in my signature). I was going to try our Marlin as well (because it is supposed to be lighter) but wanted to try out 1/16 microstepping with repetier first.

At 1/32 microstepping I have a theoretical value of 160 steps per mm for x and y (using 20 tooth GT2 pulleys, 2mm pitch, 1,8° motor).

So I want to switch to 1/16 microstepping now. I reconfigured the jumpers (single jumper on MS3) and modified the steps per mm to 80 (formula is here)

However, now the modified axis go just 50% of the requested value (ex. 50mm instead of 100) and only at 50% of the speed. I tried setting the jumpers to 1/4 microstepping but this also changed nothing - The printer moves correctly only at 160steps/mm no matter what the jumper settings are. Tried reflashing the firmware and checked if anything is shorting out the jumper pins on the other side of the board but found no problems.

What am I doing wrong? Should I modify anything else in the FW besides the steps per mm? It simply cannot be that there is no change in printer behavior no matter how the jumpers are configured....

Thank you...


Self-sourced Mendelmax 2.0-based Reprap Machine -- Ramps 1.4 & Mega 2560 -- DRV8825 ([email protected], [email protected], [email protected], [email protected]) -- genuine E3D v6 direct setup -- 350W custom silicone heated bed -- ABS 1,75mm -- Marlin 1.1.0-RC7 -- Cura 15.04.6
Re: Help adjusting the microstepping settings
March 15, 2016 12:11PM
It can be if the jumpered pins on the motherboard are shorted via traces on the board, as some of them have been known to be. Might be worth a check with a multimeter.
Re: Help adjusting the microstepping settings
March 15, 2016 01:24PM
You'd get that with a short on ms1. For what it's worth I run the same setup with DRV8825, 1/32 microstepping, mega/ramps and have used both Marlin and Repetier firmware with no signs of step rate problems at travel speeds of 250mm/s, so I doubt if maximum step rate is your problem. And if it was, you'd easily be able to tell because the problem would go away if you dropped your speeds.

Edited 1 time(s). Last edit at 03/15/2016 01:24PM by JamesK.
Re: Help adjusting the microstepping settings
March 15, 2016 02:09PM
Wow. You were right. My pins are all shorted out. Not only that MS1, PS2 and MS3 are practically on, but there is also connection between the MS1, 2 and 3. What is even more bizarre, I also have shorts between the different drivers, i.e. there is 0.0 resistance between every two random jumper pins.
Is this normal? According to this diagram it should be normal if MS1, MS2 and MS3 are on, because the one side is always VCC


Thanks...


Self-sourced Mendelmax 2.0-based Reprap Machine -- Ramps 1.4 & Mega 2560 -- DRV8825 ([email protected], [email protected], [email protected], [email protected]) -- genuine E3D v6 direct setup -- 350W custom silicone heated bed -- ABS 1,75mm -- Marlin 1.1.0-RC7 -- Cura 15.04.6
Re: Help adjusting the microstepping settings
March 15, 2016 02:47PM
Quote
JamesK
You'd get that with a short on ms1. For what it's worth I run the same setup with DRV8825, 1/32 microstepping, mega/ramps and have used both Marlin and Repetier firmware with no signs of step rate problems at travel speeds of 250mm/s, so I doubt if maximum step rate is your problem. And if it was, you'd easily be able to tell because the problem would go away if you dropped your speeds.

I am printing at 60 mm/s so speed should't be the issue. Do you have a display?


Self-sourced Mendelmax 2.0-based Reprap Machine -- Ramps 1.4 & Mega 2560 -- DRV8825 ([email protected], [email protected], [email protected], [email protected]) -- genuine E3D v6 direct setup -- 350W custom silicone heated bed -- ABS 1,75mm -- Marlin 1.1.0-RC7 -- Cura 15.04.6
Re: Help adjusting the microstepping settings
March 15, 2016 02:49PM
Yes, the full graphic. I usually print from the sd card, but sometimes over USB for short tests.
Re: Help adjusting the microstepping settings
March 18, 2016 12:14PM
I've been caught recently with one of these defective ramps boards. They look a lot like the ones currently on ebay being sold by Sintron. They might not be this brand but they do have a lot of similar features, multicolored stepping jumpers, yellow headers along one edge etc...
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