LLB - Oscillating Slow Integrator Path with Digital Filter

Moku Pro
Newest Update available currently is applied to the Moku

Hi,

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.