Scraps of text for incorporation in the VIS Meeting Minutes
Type B (Mark)
Report for the week of 2/25
- Fabian monitored suspensions during the vent.
- Terrence and Mark made lots of changes to the Guardians and RTMs:
- Added UI to take snapshots with ALIGNED/MISALIGNED channels (for late use by Guardian).
Changed "IM1" and "IM2" in channel names to "IMV" and "IMH"; also "DIO" and "BO" -> "BIO".
- Created library blocks for BIO and made all the Type B models use them.
- Tweaked the control topology to be more LIGO-style: the error signal for DC control is sensor-setpoint (not setpoint-sensor as in many controls textbooks); the input to the damping block is the uninverted sensor signal(s); there is a hard-wired -1 after the damping block representing default negative gain.
- Fabian went inside the SRM chamber and diagnosed the problem that had appeared shortly before vent. It turned out to be yaw of the IP causing a payload cable to touch. He fixed it with the F0 yaw stepper. (He had tried this earlier without success but it turned out the problem was another dead output on the stepper driver.)
- Terrence traced the geophone issue to a group of dead channels (#20-23) on the AA chassis. We tried replacing the chassis and it fixed not only the geophone issue but an issue in the TILT OL path (#24-27) that we had planned to debug next.
- We retested the BIO for stepper remote enable system and this time it was working (probably due to the refactoring of the BIO stuff in the model and/or all the restarts).
- We rebuilt all the IOP models after removing an unneeded ADC1 block (corresponding to hardware that Yoshizawa-san had removed).
- Enzo and Terrence wrote Python scripts to automate the process of adapting the control filters to the new topology (where the DAMP and DCCTRL functions are in parallel instead of series).
Plan for week of 3/4
- Enzo at Mitaka.
- Mark, Fabian Mon-Wed (Thu is farewell party).
- Final tweaks of SRM?
- Monitor (re-)pumpdown.
- Tests of new Guardian.
- Final test of stepper remote enable system (someone in cleanroom checks the lights go on/off).
- Continue monitoring SRM yaw drift.
- Setup SRM and SR3 LEN OLs.
- Work on Type B paper.
==== Plan for week of 3/11 =====
- Mark at Kamioka full week?
- Enzo at Kamioka Mon, Tue, then JPS.
- Enzo vacation, 3/5 and 3/6.
- Enzo et al. Farewell Party, 3/7.
- Enzo at JPS then final vacation, 3/13-29
- Terrence's last day, 3/29.