1. Temporary AO/AI connection to end station PDH CM board
Since ALS locking could be a time sink at times, and since going to the end station each time we want to make PDH measurement is a pain, I made the following changes.
CM boards:
| Used to be connected to | Is connected to now | |
| IN2 of the PDH CM board | Nothing | H1:LSC-[XY]_EXTRA_AO_2 |
| OUT2 of the PDH CM board | Nothing | H1:LSC-[XY]_EXTRA_AI_2 |
| IN2 of the PLL CM board | IN1 of the PDH CM board (EX, T-ed off), didn't make sense or IMON of the IQ Demod (EY), didn't makessense |
Nothing |
Note that A=1000 sinusoidal excitation in AO results in 115mV RMS (measured at EY).
2. EY: Connecting DC output of the green PDH diode to H1:ALS-Y_REFL_B_LF
H1:ALS-Y_REFL_B_LF, which is supposed to be recording the first PD on Matt's PD interface box inside the ISCTEY, has been recording noise. I connected the DC output of the green PDH diode to the first channel on Matt box with the gain of x1.
(Before this change, the DC output of the green PDH diode was found to be routed to the "TEST" TNC feedthrough inside the enclosure on the same feedthgough panel as the RF output and DB15. There was no connection from "TEST" to anywhere outside the table enclosure.
Also, the first channel of Matt box has a cable called "ISCTEY-ALS-PD6" together with a cable for DC supply, but the other end of that cable was just dangling in air over the NPRO.
I disconnected the PDH diode DC output from the feedthrough panel and rerouted it to the ALS-PD6 cable that is still dangling over the NPRO. Since I didn't have a BNC barrel I used a T. Not too proud but it should be working, see the picture.)
3. EX: Could not find where the DC output of the green PDH diode cable goes.
Like EX, H1:ALS-X_REFL_B_LF have been recording noise. The first channel of Matt box doesn't have any cable connected.
However, unlike EY, the DC output cable of the green PDH diode seems to go to somewhere inside the sea of cables on the cable tray in the direction opposite to the "TEST" feedthrough. The cable was tied to the tray using multiple cable ties together with other cables rather tightly and I couldn't find where the other end was. I gave up as I wasn't ready to undo all cable ties on the tray.
