aLIGO LHO Logbook

H1 ISC (ISC)

sheila.dwyer@LIGO.ORG - posted 21:09, Wednesday 13 November 2013 - last comment - 22:52, Wednesday 13 November 2013(8523)

pitch and yaw swapped on ISCEX PZT controllers

The pull list for end X has a lot of ?s on it, it was not clear what should be connected to what on the PZT controllers. When we first tried turning on the servos turning on the pitch servos would cause the spots to move away in yaw and vice versa, so we swapped the cables for the input to the MCL PZT controllers from X to Y. After that the pitch servos cause the beam to drift of in pitch, and yaw in yaw. Then Chris switched the sign of QPD B in pitch and swapped PZT1 and PZT 2 in yaw. Now the servos seem to be working. Clearly we need to measure the matrices in the morning.

Comments related to this report

alexan.staley@LIGO.ORG - 21:39, Wednesday 13 November 2013 (8524)

Link

(Alexa, Stefan)

We also saw that the PZT 2 (top controller, 2inch mirror) sensor was oscillating. This was temporarily fixed by placing a glove over the PZT to dampen the oscillations. We need to revisit this.

stefan.ballmer@LIGO.ORG - 22:52, Wednesday 13 November 2013 (8527)ISC

Link

Some other things we noticed:

- The PZT drive cable at the anti-imaging chassis was connected to the wrong connector - moving it to the design location brought the signals back to life.
- The QPD read-back cable was not connected to the ADC. The reason for that was that the back plate of the anti-aliasing chassis is labeled incorrectly as going to the DAC (it's an anti-image back plate). We should fix that at least with a label maker to avoid future confusion.
- we were wondering whether the PZT oscillation could be related to local feed-back from the PZT read back in the driver.