I tried to lock PRFPMI to keep thegood alignment but faild.
I briefly checked the reason and found that the GRY transmission power chaned very rapidly between 0.3 and 1.1 as shown in fig1.
This phenomena sometimes happened and considered as modehopping of GR laser.
So, I gave up to lock the interferometr tonight.
After relock the PLLs by changing the temp bias, both GRX and GRY became stable.
Then, PRFPMI RF lock succeeded without any problem.
Both DARM and MICH OLG became larger, instead PRCL OLG didn't change.
The temp in the PSL room in the last 6 days is listed in Fig.1
The temp seems to decrease by 0.01C without any intentional changes, and no PLL troubles are reported. We will keep monitoring. If the lower temp is favor, I will decrease the temp in the PSL room.
The temps are decreasing in the PSL room. No PLL unlocks were reported. So cooler condition seems to be good for GR/IR laser combination?
Because the temp in the PSL room kept decreasing, I set the precision cooler temp setting from 22.00 to 22.05 yesterday.
By the way, what happened about 6 days ago. There were jumps of temp in PT01-04.
