Motors rotating in the wrong direction while loading  

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kevin.d4
(@kevin-d4)
Active Member

Hi everyone,

I had two cables to plug between the rambo board and the multi extruder board:
- The one with 4 pins at both ends (no possible confusions)
- The one with 4 pins at one end and 5 pins at the other

I'm quite sure about the way I connected 4x5 pins for three reasons:
- I tried about all plugging combinaisons on rambo board's 5 pins rack (first line, second line, red toward the inside, red toward the outside,...)
- The one pictured in the manual is the only one which lights "RL2" LED on the multi extruder board
- It's the one I kept

Though, my extruder motors are rotating in the wrong direction, as if the 4x5 cable wasn't plugged (I tried to unplug it it didn't affect the loading routine) -> loading command creates an unloading mouvement

I tried to install the last firmware, and the previous version (3.0.12 & 3.0.13). I have a rambo 13 board (I'm sure because I tried to install the rambo 10 firmware because I was out of options and it didn't work).

What can explain this kind of behavior? What could I do to solve this issue?

Many thanks :)!

Kevin

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Posted : 12/09/2017 7:20 pm
sterling.g
(@sterling-g)
New Member

Are they loading slowly in the correct direction, then quickly reverse? Or are they always loading in the wrong direction?

If it's the first one, I have the same issue and have been waiting on a response from Prusa Research for a while. Here's my issue: http://shop.prusa3d.com/forum/original-prusa-i3-mk2-multimaterial-f26/having-issue-with-loading-t5562.html#p41394 .

If it's the second one, make sure that the first extruder is connected to the first extruder port (M0 on the original distribution board; E0 on the short, new distribution board).

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Posted : 12/09/2017 10:50 pm
kevin.d4
(@kevin-d4)
Active Member

Ok, thanks to sterling, I finally understood my issue and it's a tricky one (thank you sterling ;)). As other people might fall in the trap here is the explanation:

As motors are paired on racks, they are not equivalent: you dont have 4 motors, you have 2 "left" motors and 2 "right" motors, depending on the pulley position. It comes out that "left" motors and "right" motors have opposite rotation directions:
- If the motor is left to the pulley, it will unload clockwise, and load counterclockwise
- If the motor is right to the pulley, it will load clockwise, and unload counterclockwise

The multi material board is configured to have motors plugged in a "Righty Lefty Righty Lefty" order, so with the rightest motor on E0 and the leftest on E3.

So if ALL your motors are rotating in the opposite direction you want, it might be because you plugged them from left to right instead of from right to left.

It seems pretty obvious but in order to help dumb people like me to be aware of that, maybe this can be added somewhere in the documentation: "Watch out, motors have to be plugged from right to left, or they will rotate in the opposite direction you want".

Have a nice day everyone 🙂

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Posted : 13/09/2017 1:48 am
austin.puetz
(@austin-puetz)
New Member

Sterling, i am having the same problem as you, what was your eventual fix?

Posted : 09/09/2019 10:58 pm
david.a66
(@david-a66)
Reputable Member

you can add a comment to that step in the on-line manual to help other users in the future

Posted : 09/09/2019 11:24 pm
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