[Sheila, Jenne]

This is starting to feel a bit like we're using popsicle sticks and duct tape to make a splint and hold things together, but we're still having trouble with the vertex ASC at high powers, so we have tried implementing a dither/ezcaservo combo loop for MICH pitch.  As of now, Sheila has a script that will turn on a dither line for BS pitch and set up the demodulators in the ADS.  The script then sets up a cdsutils ezca servo to move the offset of ASC-MICH_P to zero the output of the demodulator. 

Earlier, we tried just a regular dither servo, moving the BS to minimize the demodulated version of AS90, but that wasn't working.  Note that earlier today we removed the AS90 element from the SRM dither loop, so the SRM dither now only looks at POP90. 

Since adding MICH offsets worked okay over the weekend to fix the sideband buildup after the POP offsets are adjusted, we thought we'd give the demodulator-adjusted offsets a try. This is well after fixing the TCS situation described in alog 29237.

On at least one occasion, this new system didn't keep up with the IFO heating when starting the offset from zero, so now it starts the pit offset from the value that Sheila et al. found the other day.

We've tried it now with both BS pitch and yaw under this new additive-offset-like configuration, but the sideband buildups still seem to be decaying.  Perhaps SRM dither should go back to the AS/POP ratio, and BS should be servoed to maximize POP18?

Side note:  We have got to find time to re-look at the OMC ASC.  Engaging the dither loops once again rails the OMC suspension.  This was happening last summer, and then the problem somewhat mysteriously went away, so I don't have any magical solution right now.  But this certainly can't be good for our noise.