Wrote a a new guardian (VIOLIN_DAMPER.py in /opt/rtcds/userapps/release/isc/common/guardian/) that can figure out the best damping phase for the violin mode damper. (This automates a usually very boring task.)

The code relies on each modal damper filter module being set up the same way, with a narrowband filter in FM1, a -60deg filter in FM2 and a +60deg filter in FM3. This setup allows setting the feed-back phase in 60deg increments. E.g. 240deg = negative gain & +60deg filter.

The code loops through the 6 possible phase settings (0deg,180deg,60deg,240deg,120deg,300deg). For each setting it waits for the filter to settle, takes a peak reference value of the mode strength, then waits for a specified time and measures the mode strengh again, calculating the after/before ratio. If the mode grows too fast, the code stops earlier to avaoid a runaway, and procedes to the next phase setting.

After loopig through all settings, it sets the module to the best daming setting.

This seems to work reliably as long as we are not hampered by closely neighbouring modes, and should reduce the repetitive work in modal damping.

As example, I attached the output of the Guardian when it was applied to SUS-ITMY_L2_DAMP_MODE8. Plot 1 shows the violin mode strength over the 15min the code ran, screen shot 2 shows the Guardian message output.