LLB - Oscillating Slow Integrator Path with Digital Filter

Moku Pro
Newest Update available currently is applied to the Moku


we have an interesting problem with a working workaround, so its just an inconvenience but still, I wanted to make a note of it here. We employ one Moku Pro to lock two lasers simulatenously via two LLB-Instruments. Both receive a quite noisy signal so we feed it through the Digital Filter Box before we hand it off to the LLB-instruments.
Here is an image of our configuration:
(See (1.) in uploaded image)

Also the configuration of the digital filter box:
(See (2.) in uploaded image)

The bug seems to happen (sometimes - I’d say 50:50 chance) whenever a parameter is changed in the filter box. For example the upper or lower frequency-boundary of the bandpass.
This seems to trigger an oscillation of the slow controller path of the laser lock box (in slot 4 of this configuration) as seen by the following image:
(See (3.) in uploaded image)

The oscillation cannot be stopped in any way whatsoever (at least what I’ve tried yet). Not with stopping the signals, changing pid or filter parameters, nothing. The only thing that helps, is deleting the laser lock box instrument followed by reinstating it as it was before. This only takes 20s or so but still is anoying and also quite scary since the slow path-laser-hardware is not supposed to get such quite violently oscillating signals.

thank you for your help.

PS: Btw. see the inputs at Slot3 for the Waveform generator? They’re not necessary but I didn’t find a way yet to remove them since they were autogenerated with the instrument. But still, the Moku is really cool and proved to be invaluable in its first two weeks of use here. Thank you.

I have the same problem using 2 Laser Lock Boxes in Multi Mode. The slow output has the same feature, I was not able to get rid of it rendering the lock unusable.

We have recently updated our LLB UI to have a different lock staging interface. Are you still experiencing this issue with the 2.6.0 software?

I can confirm this behaviour to still be present in the new 2.6.0 version. (As well as the beta versions 2.6.1b…)

For this issue, when it occurs could you try tapping the blue button on the top right corner of the DFB instrument and select ‘Rest Filters’ and see if that changes the waveform?

Following up on this bug for the LLB and DFB, this has now been fixed as of 3.0.0. If you see any other problems please feel free to post to the forum anytime.