Back to loss measurements.
I replaced the PD I've been using for the AS beam.
I misaligned the x arm.
I tried to lock the y arm, but PRC was locked so I could was unable. Gautam reminded me where the config scripts are.
The armloss measurement script needed two additional modifications:
- It was setting the initial offset of the PIT and YAW demod signals to 0, but due to the clipping on the heater we are operating at an offset. I commented out these lines.
- When the script ran UNFREEZE_DITHER, it was running it using medmrun. The scope script hadn't been using this, and it seemed that when it ran UNFREEZE_DITHER in this way the YARM_ASS servo was passing only '0'. I don't really know why this was, but when I removed the call to medmrun it worked.
I ran successfully the loss measurement script for the x and y arms. I'm getting losses of ~100ppm from the first estimates.
I made the following changes to the lossmap script:
- make the averaging time an input to the script, so we can exceed 2 second averages
- remove anything about getting data from the scope, replace it with the correct analogues to save the averages for POX/POY refl, MC trans, op lev P/Y, and ASDC signal.
- record the GPS time in the file with the cds averages (this way I can grab the full data)
- Added a step in the lossmap script to misalign the optic, so we can continue getting data for the 'misaligned' state, both for the centered and not-centered measurements (that is, for every position on the lossmap).
When the optic aligns itself not at the ideal position, I'm noticing that it often locks on a 01. When the cavity is then misaligned and restored, it can no longer obtain lock. To fix this, I've moved my 'save' commands to just before the loop begins. This means the script may take longer to run, but as long as the cavity is initially locked and well aligned, this should make it more robust against wandering off and never reacquiring lock.
I left the lossmap script running for the x-arm. Next would be to run it for the y arm, but I see that after stepping to a few positions the lock is again lost. It's still trying to run, but if you want to stop it no data already taken will be lost. To stop it, go to the remaining terminal open on rossa and ctrl+c
the analysis needs:
- Windowing
- Filter, don't average
- detrend to get rid of the linear drifts in lock that we see.
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