What is the state of accelerometer support and input shaping?

zapta · 3 Oct 2021, 05:52

My new no-SBC Duet5+ printer got stabilized and I would like to dip into the accelerometer measurements and input shaping.

What accelerometer should I get (an add-on one, not a tool board)?

What can I do with now? Is input shaping ready for testing? If not, can I do some vibration/resonance analysis? Anything else?

dc42 · 3 Oct 2021, 06:10

@zapta see https://duet3d.dozuki.com/Wiki/Accelerometers for what accelerometer to get and how to connect it. RRF 3.4beta supports input shaping, configured using the M593 command. There is an input shaping plugin for DWC to help analyse the accelerometer data.

zapta · 3 Oct 2021, 06:27

Thanks @dc42, I will order a LIS3DSH board.

What cable length is practical with the Mini5+? Going through the Voron V2.4 drag chains can result in a long path, around 2m IIRC.

EDIT: Just ordered this one https://www.amazon.com/gp/product/B082W63MWL

dc42 · 3 Oct 2021, 07:14

@zapta 2m may be pushing it. I have tested 1m. Make sure you wire the cable as I described in the page I linked to, with the CS conductor not next to any other signal wires.

jay_s_uk · 3 Oct 2021, 08:24

@zapta I have tested a 2.7m USB-C cable and have had success

zapta · 3 Oct 2021, 16:23

@jay_s_uk said in What is the state of accelerometer support and input shaping?:

@zapta I have tested a 2.7m USB-C cable and have had success

Thanks @jay_s_uk. BTW, the documentation mentioned I2C and SPI, which one is better for this application?

jay_s_uk · 3 Oct 2021, 16:54

@zapta SPI is all that's supported in this implementation

zapta · 3 Oct 2021, 17:20

Thanks @jay_s_uk. My accelerometer should arrive tomorrow and I can't wait to get some graphs.

I am quiet happy with the way my printer prints and even didn't turn on pressure-advance but sometimes things get into resonance which makes the printer noisier that I would like.

CabalSoul · 3 Oct 2021, 18:40

@jay_s_uk

Since I know that you have also a predator, do you care to share the result of your resonance analysis?

Sadly I have more resonant frequencies and the input shaper isn’t helping much in my case. The most prominent frequency is around 41.5 hz and it looks like the zvd is my best option.

I was Even wondering if installing steppermotor
Dampeners would improve my situation.

zapta · 11 Oct 2021, 05:05

Before I connect and cause any damage, does this wiring diagram look right? It's for a Mini5+2 and this accelerometer https://www.amazon.com/gp/product/B082W63MWL and is based on the information here https://duet3d.dozuki.com/Wiki/Accelerometers

T3P3Tony · 11 Oct 2021, 09:59

@zapta It looks good to me

zapta · 11 Oct 2021, 17:33

Thanks @t3p3tony. My printer currently has the stable version below. Do I need to upgrade (to what version?) to use the LIS3DSH and input shaping?

T3P3Tony · 11 Oct 2021, 17:47

@zapta input shaping is implemented in 3.4b, We should be releasing 3.4b5 soon which would be my recommendation as 3.4b4 has a bug with pausing that you may want to avoid. You can capture the data with 3.3 using the accelerometer plugin (different from input shaping plugin)

zapta · 11 Oct 2021, 19:06

Thanks @t3p3tony, I will play with the accelerometer with 3.3 and will wait for 3.4b5.

pkos · 15 Oct 2021, 07:34

This post is deleted!

pkos · 15 Oct 2021, 07:34

I'll latch on to this topic and ask about the future plans of Input Shaping and more specifically - separate values for X and Y.

With CoreXY - I values will be quite close together unless I mess up the build totally.

But with bedslingers - the variance to me has a chance of being much bigger and not always much can be done about it. Individual values would help here.

So... do you have plans to introduce individual settings for X and Y or is it going to be just one value for good?

T3P3Tony · 15 Oct 2021, 11:27

@pkos we will evaluate separate input shaping for X and Y, there is certainly a logical argument for it. As it stands it wont be part of 3.4 release though, so for consideration in 3.5.

pkos · 15 Oct 2021, 18:05

@t3p3tony Understood. Thank you for the answer.
Now I have to decide whether I will wait for 3.5 or sell my bedslinger (just as I was starting to like it ).

zapta · 15 Oct 2021, 18:22

@pkos said in What is the state of accelerometer support and input shaping?:

the variance to me has a chance of being much bigger

Have you tried to measure X and Y independently with the current RRF and see what you get?

pkos · 15 Oct 2021, 18:26

@zapta That's not the issue. We can already measure X and Y separately.

The problem is that you can only pick one value for both axis for the input shaper configuration and they can be quite different.

I am always quite reluctant to use comparisons to others, but unfortunately here Klipper does have the upper hand and allows for separate values on X and Y in it's input shaper config.

And I don't like klipper. Not one bit I like my duets.