Duet 2 wifi AND LIS3DH

[dc42]

@luc did you have any fans running when you did the measurements? If so then the 74Hz spike may have been vibration from a fan. 74Hz is 4440 rpm.

[luc]

@dc42 said in Duet 2 wifi AND LIS3DH:

@luc did you have any fans running when you did the measurements? If so then the 74Hz spike may have been vibration from a fan. 74Hz is 4440 rpm.

No, fans off. I did the standard test as it is set up by default. I know I have a very small play on the X-axis linear guide (it is a XY core). But I am not sure if the 74Hz is caused by the guide or all by the guide. Tomorrow I will try to tie a weight on my head to see if it changes. If you have any ideas for some tests I would be happy to do them. Thanks for your interest.

[dc42]

@luc the movement of the belt over the toothed pulleys can also cause vibration. To check this, repeat the input shaping test moves at a different speed and see whether the frequency changes. Alternatively, un-check the box to take readings over the whole move and see if the peak goes away.

[luc]

hello to everyone,
I mounted the sensor in a different position and with a different and more stable support. Now the graph has changed and the 74Hz spike has disappeared. So I think this is fixed.

I have a question, in the graph, the Y Amplitude axis, does it indicate the displacement in mm?
(0.018 = 18/100 of a mm?)

[luc]

Other thing, from this further simulation graph it seems to me that MZV intervenes on a larger part on the frequency peaks in my case than ZVD. Have I interpreted this correctly?

Sorry for too many questions but I am trying to understand the logic of its operation.

[dc42]

@luc yes MZV has quite a wide bandwidth, however the amount of reduction is not as great as ZVD. In your graph, ZVD cancels the 44Hz peak almost completely whereas MZV cancels it by about 90%.

BTW when dealing with such a sharp peak you may get better results of you reduce the damping factor from its default value of 0.1 to e.g. 0.05.

[luc]

@dc42
I have a question, in the graph, the Y Amplitude axis, does it indicate the displacement in mm?
(0.018 = 18/100 of a mm?)

Thank you

[dc42]

@luc no they are fractions of 1g acceleration.

[luc]

Hello everyone,
I would like another clarification.
Doing the test that DWC proposes by default by clicking on the “Record Motion Profile” button, the parameters it uses for both acceleration and acceleration profile are the ones set in config.g?
So are they M201 for acceleration and M566 for acceleration profile?
Thank you

[dc42]

@luc M566 is not relevant here because RRF does not use jerk what starting a move from standstill, or when ending a move at standstill.