Strange problem with repetier host

LowRider CNC Troubleshooting
1

I hadn’t used my lowrider for several months and when I powered up today and moved the axes using repetier host I got some strange behaviour.

I moved X axis 10mm to right a couple of times and then when I tried to move 10mm to left it went right again. Of I tried again to go left it would still go right for another 2 attempts and then would move left.

Similar behaviour with Z axis and the distance moved appears to be about 3x what it should be.

Moving manually using the TFT touchscreen works correctly for all axes.

I’m siding skrpro1.2 board with TFT35 board from V1 and have successfully been using the machine prior to a bit of a break.

Any suggestions about what I should do would be much appreciated.

2

If you send the 10mm movement commands via the terminal in RH does it do the same thing? For instance:

G91 ; set to relative positioning
G0 X10 ; move the X axis 10mm, test + and - values, direction depends on your setup
G90 ; set back to absolute positioning once you're done playing around with the G0 command

If sending commands do what they’re supposed to then it could be an issue with the GUI buttons in RH. Maybe try updating the software?

3

Same thing here! Sometimes I will home my machine, then jog to the right 100mm about 3 or 4 times to get to 300mm or 400mm on the X axis. Instead of moving 400mm to the right, it will instead go about 200mm to the right, 100mm left, and then 100mm to the right again, or something like that. Very random and peculiar movement. Not sure if it is firmware of Repetier. Seeing how it has not always been happening in the past, I would assume its a new bug in Repetier.

4

Repetier uses it’s own copy of the coordinates for some reason.

So if, for example, the machine turns on at 0,0,0. Then you ask for jog 10mm+X, it will send a command G1 X10. But if you were actually at X=20, it would go left instead of right.

The easiest solution is to not switch back and forth between the screen and RH. There is also a sort of special RH command @isathome that will tell RH it is at the origin (you can use it after sending G92).

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5

Thanks for the advice.

I have updated to the latest version of Repetier and will try out moving using the command prompt rather than GUI

6

Thanks jeffeb3, all sorted now. I think the issue was that I had moved using the TFT screen and then hadn’t reset z position in repetier before using this to move again. Rookie mistake since I hadn’t used my lowrider for a while.

Solution is to keep using it so I don’t forget stuff!!

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