Printer Model: BLV MGN12
MCU / Printerboard: DUE + RADDS
Host / SBC Raspberry Pi 3 printer.cfg (7.6 KB)
Hi everyone,
I’m still relatively new to Klipper.
I’ve got everything running now, except for the “Input Shaper” issue.
The ADXL345 from Fysetc is now running, which was hell for me.
What’s strange, though, is that when I enter “TEST_RESONANCES AXIS=X,” the print head always moves a good 30 mm to the left and then right again, instead of just vibrating like in the typical YouTube videos.
Can someone explain to me what’s causing this?
I had set the acceleration values to 10,000, and even to 20,000 for testing. Nevertheless, the print head moves comfortably left and right at a snail’s pace until it’s run through all the frequencies.
Well, that only mean that in your case here is not enough resonance power.
So, there is mostly no peaks.
Generally good graphs should be in a scale of 1e4 (~1g+) (>10000)
In your scale, there are 1e3 (0.1g) (~1400), which is just looks like a normal vibration.
Probably for good measurements, you may want to increase the intensity:
[resonance_tester]
accel_per_hz: 75 # default, you may want to increase it by 10 or more.
#with MAX HZ 133 ~ 75 * 133 = 9975 max acceleration during test.
Such a spectrum could also mean that your axes are actually binding or not moving freely. For a better understanding see Interpreting the Input Shaper Graphs
Most probably, you will not be able to tune or use IS with a closed loop.
Simply because they are not compatible with each other.
IS assumes there is an open loop, and we do some physical hacks to make the system behave like we want (like travel angles without jerks and oscillation).
On the other hand, closed loop will try to do basically the same, but instead use PID/PIV & etc, which will fight with oscillations.
You can try to tune IS, so it will try to smooth corners, but I suspect that without a disabled closed-loop, you will not be able to get reliable results, either by printing or by analyzing accelerometer data.
Back then, I had a lot of problems with Repetier, including layer shifts. That’s why I upgraded to closed-loop drivers.
Maybe i could change my Due+Radds with a BTT SKR Mini E3, V3.0 .
In this case i could use the TMC2209 with UART
But first, i keep on going on my DUE+RADDS Combo
There are a few considerations. First, you ran several resonance tests for the same axis sequentially, and the script picked up all the results and combined them together. You can retry the test, after powering off and turning on, the previous test results will be deleted. And you can also try increasing the accel_per_hz option (you can actually set it to 75, it is 60 now by default). Closed-loop stepper drivers are not necessarily a problem by themselves (the close-loop only controls the position of the drivers, but not the toolhead), but maybe your specific drivers could have some unknown issues.
