The smoothing factor was set to 0.999 on all CPs. To confirm that the device is still active and responding and not in an "inactive state" (which happens if smoothing factor is set to its limit of 1.0), the LLCV trends over 30 days are posted for the seven CPs (CP3 excluded).

The smoothing factor algorithm (from EPICS integrated into Beckhoff):

if SMOO is 0 or INIT is True, VAL = val
else VAL = val * (1 - SMOO) + Previous_vale * SMOO

*this implements a first-order infinite impulse response (IIR) digital filter with z-plane pole at tau=-T/ln(SMOO), where T is the time between record processing

Attached are screenshots for the past 7 days of optical lever trends for PIT, YAW, and SUM.

This completes FAMIS request 4683.

Peter was in the PSL enclosure and looking at the FSS - his alog will give details.

He's done so I'm starting to lock.

Attached is a plot of the diffracted power versus offset slider position.
With the current slider setting of 6.35, we are diffracting around 3 W of
light.  Even if the output power of the laser was only 100 W, this would
be 3% not the indicated ~15%.  However we know the output power of the laser
is greater than 100 W, so obviously the percent diffracted light is even less
than 3%.

   This is noticeably less than when the ISS was last tuned up.  Back then a
slider setting of 6.35 would diffract about 7 W.  Although nothing has changed
hardware-wise, it is possible that the 80 MHz source for the ISS AOM is no
longer providing the ~32 dBm, or the AOM driver is deteriorating.




Jason/Peter

With the pre-modecleaner unlocked the output of the locking photodiode was between
-1.070 V and -1.080 v.  Locked was between -170 mV and -185 mV.  This gives the
pre-modecleaner visibility to be between 83% and 84%.


Jason/Peter

Attached are measurements of the ISS transfer function performed after a
minor alignment adjustment to the ISS AOM.  These were taken with the gain
slider at 6 dB and 9 dB.  The offset slider was left at 6.35.

    With the gain slider at 6dB the UGF is about 54 kHz; 9 dB 70 kHz.
However there is considerable peaking in the noise spectrum.  The free-running
noise is also attached.

    All measurements were taken with PDA which was the in-the-loop sensor
at the time.  The reference signal was at -2.00.  At this setting the measured
DC output of PDA was -8.70 V.



Jason/Peter

Attached are the transfer function measurements of the FSS taken yesterday afternoon.
The first two plots are taken with the common gain at 16 dB and fast gain of 22 dB.
The second measurement (C16F22-2) I think was affected by the modecleaner trying to
acquire lock, which might explain the notch-like feature just past 200 kHz.  The
UGF in both measurements is about 195 kHz.

    The third measurement, taken with a common gain of 20 dB and a fast gain of
22 dB is, I suspect, also affected by the modecleaner trying to acquire lock.



Jason/Peter

This is as far as I have been able to get the IFO tonight. I tried to set the intent bit, but it will not engage. I have set the Ops Observatory Mode to Observing.

Ross and I are the only ones in the control room. The last lock was lost at ENGAGE_ISS_2ND_LOOP from a pringle mode on ETMY.

Took advantage of laser being down (aLOG #28142 & 28145) to change the water filters in the chiller room. 
Swapped out the Diode Chiller filter. The filter looked fine, but changed it out anyway to see if this had any effect on the rising PSL chiller pressures. 
Did not change the Chrystal Chiller filter. The filter bracket is poorly mounted to the wall and is coming loose. Need to secure the filter bracket to the wall before unscrewing the filter canister.