My goal of today was to lock PRMI without using AS55 and it is 50% successful.
The sideband-resonance PRMI (SB-PRMI) was locked with REFL33_I and REFL55_Q for the PRCL and MICH control respectively.
The carrier-resonance PRMI wasn't able to be locked without AS55.
(it looked no clean MICH signals at the REFL ports.)
The motivation of not to use AS55 came from the suspicion that AS55 was injecting some noise into MICH (#5595).
So I wanted to try another RFPD to see if it helps the stability or not.
The lock of SB-PRMI was quite stable so that it stayed locked more than 30 minutes (it ended because I turned off the servos.)
Then I briefly tried DRMI while PRCL and MICH kept locked by the same control loops, namely REFL33_I and REFL55_Q.
The lock of MICH and PRCL looked reasonably robust against the SRCL fringes, but wasn't able to find a good signal for SRCL.
I think I am going to try locking DRMI tomorrow.
- - settings
Demod phase for REFL55 = -45.3 deg
Demod phase for REFL33 = -14.5 deg
Whitening gain for REFL55 = 4 (12 dB)
Whitening gain for REFL33 = 10 (30 dB)
MICH gain = 100
PRCL gain = 8
+ I removed an iris on the ITMY table because it was in the way of POY. See the picture below.
+ I found that burtrestore for the ETMX DC coil forces were not functional.
=> currently ETMX's "restore" and "mislalign" buttons on the C1IFO_ALIGN screen are not working.
=> According to the error messages, something seemed wrong on c1auxex, which is a slow machine controlling the DC force.