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X axis dancing

Open Sekai1942 opened this issue 5 years ago • 13 comments

Hi. i just installed s42b on my diy printer and did the calibration and it works but the x axis when i try to move it it just goes back and forward really fast.I think the whole asamble is to large in weight and it overshouts when moving then try to compensate then it overshouts in reverse and that becames a loop. I try to lower the accelaration but the same thing. The Y axis does the same but not every time (as shown in video). And when i turn off the motors in the interface below, the y axis i can move it but the x axis the motor stays energized but there is no compensation meaning the board is not active for close-loop. Any ideea how to solve this? https://drive.google.com/file/d/1P0TRuBtJh8re5k-FxD4gFDRKnzX-ddsW/view?usp=sharing

Sekai1942 avatar Oct 23 '20 17:10 Sekai1942

Did you calibrate without load (belt detached)? That would be my first shot as imprecise calibration kills the PID loop quite easy.

If the calibration is fine without load I would check for the PID settings of the S42B as they likely need tuning for heavy loads. Can be done either via serial control (see the manual) or via flashing the firmware directly (my prefered way). Oszillation should be either too much I or P or to little D. Instead of I=10 a few use I=2 or even I=1. Just reduce I until you get no oszillation. If this is not possible, reduce P as well.

I am not sure, how far Jan is already for his fork to get PID tuning more user friendly: https://github.com/swanepoeljan/TrueStep

Maybe you check the other issues in this repo as well as there are some tunings required for Marlin 2.0.x as well.

Quas7 avatar Oct 23 '20 19:10 Quas7

You are right. i calibrated without load.I calibrated the y axis with load and it looks ok now but the x axis i have no way to reach out to the buttons. i will have to serial control it. thanks.

Sekai1942 avatar Oct 25 '20 09:10 Sekai1942

btw how to upload the firmware?

Sekai1942 avatar Oct 25 '20 12:10 Sekai1942

for the flashing of the FW you will need an stlink dongle (clone). More details are here:

https://github.com/bigtreetech/BIGTREETECH-S42B-V1.0/issues/3#issuecomment-691197566

Quas7 avatar Oct 25 '20 15:10 Quas7

for the flashing of the FW you will need an stlink dongle (clone). More details are here:

#3 (comment)

Thx for the replay. I order the dongle about a month ago for different project. The current problem i have is i cannot modify the pid from serial. It gives me a response back but when i try to change the parameter, it gives back crc sum error. What i am doing wrong?

Sekai1942 avatar Oct 28 '20 14:10 Sekai1942

@Sekai1942 I never used the serial interface and always flashed my changes directly. So, I can not help much on this one but there are other issues discussing on this here, I think.

Quas7 avatar Oct 28 '20 14:10 Quas7

@Sekai1942 Did you see this document. It explains how to calculate the checksum.

swanepoeljan avatar Oct 28 '20 19:10 swanepoeljan

yes i found out how to modify the parameters.

Sekai1942 avatar Nov 09 '20 16:11 Sekai1942

In the meantime I have added support for the original firmware in my terminal program which you could also use for changing the PID gains.

swanepoeljan avatar Nov 09 '20 16:11 swanepoeljan

Does this firmware also work with the s42b V2.0 or is it only suitable for the V1.0?

robtheminnie avatar Jan 04 '21 12:01 robtheminnie

Since V2.0 uses the STM32F103 and probably also use a different pin out it will most likely not work. As for the terminal program, I am not sure, if they kept their protocol the same it could probably work.

swanepoeljan avatar Jan 04 '21 13:01 swanepoeljan

@swanepoeljan, thanks for the info. I commented in another issue, #32 , about having the same problem. The user fixed the issue by updating to your firmware fork. However, as I have V2.0 boards, this isn't possible. Are you familiar with the #32, and behaving indicated, with vertical lines and ringing. I'm assuming it's incorrect PID gains. Any thoughts?

robtheminnie avatar Jan 04 '21 15:01 robtheminnie

Haven't seen that post, glad to hear it worked for him. I would also try playing with the gains to see if it helps, maybe he can share his printer model and gains that worked for him.

swanepoeljan avatar Jan 05 '21 07:01 swanepoeljan