In an effort to eliminate the need to connect and disconnect shutter cables during vent we have moved the shutter logic controler to the rack from the table.  Also replaced the BNC cables with Yellow BNC cables so they can be easily identified.
See attachment.

Krishna,

Jenna and I had noticed that L4C 7 didn't appear to be working. L4C is close to the c-BRS, so it would have been good for comparison. In order to test if it was the instrument or the electronics, I temporarily swapped the cables with those of L4C 8 going in to the SUS rack at the LVEA. Now L4C "7" appears to be working and L4C "8" is not, indicating that the problem must be on the instrument side (or the pre-amp, I guess?). I'll swap it back in the afternoon.

  Posted below is a 45 day trend of the TCS laser power compared to operating temperature. There is a drop in power and temperature on 07/19/16 (aLOG #28506). During the HAM6 vent the RF driver was replaced (aLOG 28837) but was never tested due to lack of a beam. After the vent TCS-Y came back at ~16W with a temp of 22.   

Dear Colleagues,

As of now, LLO is closed until further notice due to widespread flooding in the area that prevents access, including emergency access.  I expect we will be able to reopen on Monday.

Any personnel or visitors on site now should immediately leave, taking US-190.  Explicit permission from either myself or Richard Oram is now required to be on site.

More details will follow, but I did not want this message delayed.  As always, liaisons should be in touch with your visitors to convey this message.

Joe

Joseph A. Giaime, Observatory Head, LIGO Livingston (Caltech); Professor of Physics & Astronomy (LSU).

phone at LIGO: +1 225 686-3169.

SEI: All back to normal after vent
SUS: All Ok
CDS: Looking into several read-back issues. Will need to do a restart of NDS1 this morning.
PSL: OK. Looking into the low power from the TCS-Y laser.
VAC: No report
FMC: No report

Relocking and commissioning work today.

I have taken camera images of the OMC R and ASAIR beam. This was primarily to compare the beam quality before and after the OMC swap. However, I did not find any obvious or significant change in the beam shapes. See the attached and compare them to the ones in 28718. Also the data is attached as well.

Stefan and Sheila working on shutter control logic. I helped resolve problems with h1ecatc1. Had to restart EPICS IOC and copy updated PLC2 to target.

23:32 UTC Gerardo to HAM6 area to check on vacuum equipment
23:39 UTC Gerardo back
03:05 UTC Joe to Y2-5 to watch meteor shower with telescope
04:30 UTC Stefan and Sheila done working on shutter control logic. Kiwamu starting work.
06:17 UTC Kiwamu to end X to investigate green laser electronics
07:00 UTC Kiwamu back

I was able to get the Y arm green power to around 1 with LOCKED_NO_SLOW_NO_WFS, but if I put it on INITIAL_ALIGNMENT it would start to be driven away. Kiwamu was investigating the X arm.

After CO2Y was powered on today, we noticed that the laser power was as low as 16 W which should be nominally 60-ish W. See the attached. This is the one with the RF driver recently swapped (28837). Needs more investigation.

... why we did all this testing single bounce, and didn't try to lock anything:

There was a 7.2 quake, includiong some stron aftershocks, gently rocking the planet for the last 3h...

Sheila, Stefan,

We debugged Daniel's Beckhoff based AS port protection logic (more on that in Sheila's alog) and updated the guardian wrapper code to work with it.

MEDM screen description (figure 1):
AS Trigger PD (top left): Is the trigger PD (ASC-AS_C_SUM), as seen by Beckhoff within alowable power limits (i.e. there is power on the PD, but also not too much)
AS Trigger Logic (bottom left): Control of the fast trigger logic - feeds into the fast shutter and into the PZT shutter. (Note: manually closing this trigger actually fires the fast shutter.)
Fast Shutter (top middle): Control of the fast shutter (Note: manually closing the shutter here closes  the fast shutter SLOWLY.)
PZT Shutter (bottom mddle): Readbacks for the PZT shutter.
Protection (right): Logic and readback for the shutter status and testing.

The protection implements Daniels ECR E1600248 testing. More on that in SHeila's alog.
Note that the Beckhoff code cannot check the light on PDs downstream of the shutter. We indend to add a check of the downstream diodes into the FAST_SHUTTER guardian.

FAST_SHUTTER guardian:
This guardian is intended to implement the rest of ECR E1600248. Currently, it checks whether the AS_PORT_PROTECTION needs a test (Beckhoff readback), runs that test by poking Beckhoff if needed, and verifies that all the light levels are adequate before going to READY.

If any of the conditions are not met, it stops in SHUTTER_FAILURE and waits for human action.

The ISC_LOCK guardian will be updated to require the FAST_SHUTTER guardian to be ready before proceeding to full lock.
 

Items of ECR E1600248 still to be implemented:

1) Automatic check on lock-loss that the shutter worked as intended. If not, command PROTECTION_AS into Fault, and raise audio warning. This part however can only be implemented when seeing real lock-losses. So we intend to initially require a human to look at every lock-loss - the corresponding medm button is implemented - see alog 29001.

2) Augment the FAST_SHUTTER guardian to monitor the photodiode levels during the Beckhoff testing, and require that the downstream light is cut off and doesn't come back.

We triggered the fst shutter a couple of times by lowering the threshold (i.e. ensuring that the alanog electronics fires the shutter), and wee verified that we didn't see any bounce after 60ms to 100ms (as loged before in alog 28958 ).

Attached are plots for one trigger, on different time scales.

[Jenne, Stefan, Peter, TJ]

We now have a new guardian node, FAST_SHUTTER, to monitor the function of the fast shutter.  So far this does not interact with the PZT shutter. 

Attached is the guardian graph of how it works for now. 

• Down is currently an empty state.  The only thing I can think to perhaps add here is re-requesting that the shutter be closed. 
• CheckReady is the big state that does most of the work.
  • If the Beckhoff logic says that we need to run the tests (either it's been more than 48 hours, or something is wrong), then execute the test script that's also accessible from the new medm screen.
  • If we don't "need" tests, then check several of the ready bits and error flags to make sure they're all clear.  Also check that we have some non-zero amount of light on the trigger photodiode (threshold currently set to 0.25, typical value during 2W DRMI lock is 0.3 or so).
  • If everything is fine, go to the Ready state
• Ready is an empty state like that of ISC_LOCK, to help make it clear that you've successfully completed the Check state.
• TestShutter executes the Beckhoff test script.  If the shutter passes the tests, the script should clear the TestNeeded EPICS bit, so that when TestShutter returns to the CheckReady state, it'll go through with the rest of the checks, and hopefully return Ready.  If the shutter fails the test, the guardian instead returns ShutterFailure.
• ShutterFailure should be impossible to get out of without human intervention.  It's an empty state, but it'll keep things stuck until someone checks on things.
• IFO_Locked is currently empty, but should be made to watch for locklosses.  This is the nominal state for Observing.
• Lockloss should run some small analysis to ensure that the shutter did successfully close.  If it did not close, this should return to the ShutterFailure state, and keep us stuck there until a human checks things out.  Otherwise, it'll return Down and be ready for the next acquisition sequence.

So far, this is not incorporated into the main ISC_LOCK guardian.  However, ISC_LOCK Down should probably request Fast_Shutter's Down.  Somewhere around DRMI_LOCKED we should have the ISC_Lock guardian request Ready from the FastShutter guardain.  We shouldn't be able to continue locking unless the FastShutter says that it's Ready.  Somewhere like DC Readout, we should put the FastShutter guardian in IFO_Locked.

We hope to be able to test the functionality of this new guardian tomorrow, after ISCT6 is put back in place.

[Corey, Betsy, Fil, Peter, Calum, Stefan, Koji]

Summary

- The ISC portion of the HAM6 vent work has been completed.

- Shield isolation of the in-vacuum cables was confirmed.

- The fast shutter was reinstalled on the table after some modifications.

=> Ready for the SEI mass balancing and other exiting procedures. OMC PZT HV is still on. Remeber to turn it off before pumping down.

Some details

- Shield isolation: It is always confusing to check the shiels isolation on HAM6 because of several reasons.

1. All the OMC cables (OMC DCPDs, OMC QPDs, and OMC PZT) are sharing their shield on the OMC breadboard. Therefore one needs to remove the related three DB25 cables from the flange when the shield shorting is checked for them.
2. The beam diverters connects the shields of their cables shorted to the ISI table. Therefore the shorting needs to be checked with the beam diverter disconnected at the mighty mouse connectors. When the test is done, the connectors need to be restored and the function of the beam diverters should be checked again.
3. The picomotors don't short the shields on the table. Check them as usual.

We initially had several cables shorting to the chamber but all of them but one happened at the slack of the cables right inside of the flange. The last one happened on the DB25 cable before it climb up to the vertical wall of the ISI.

- The fast shutter modification / reinstallation

(Photos are supposed to come later.)

1. The new bobbin came in for replacing the moving part of the shutter.
2. The wire stays were modified to have the bobbin wires more relaxed. Also it should allow us to have more clearance of the wires from the beam towards OM1.
3. To allow this modification, the direction of a coil wire (shorter, negative, lower slot) in the terminal block was flipped (Corey's attachment 1).
4. The shutter was placed on the ISI table. Then we found that clearance of the wire is in fact poor. We bent one of the wire clamps (Corey's attachment 2: The clamp at the right side of the shutter) and also adjusted the wire length to have 8~9mm clearance from the beam now. (Corey's attachment 3: The clearance does not look great in the photo but in reality the beam is clearly away from the wire.)
5. The shutter function was tested with the shutter test controller. No HV was used during the test.
6. The beam alignment from the shutter to the gold coated tube was checked. The beam is on the tube but close to the top edge of the tube aperture when the shutter mirror wobbles. We believe this does not create any issue even if the beam falls off from the dump as there is nothing sensitive behind the tube beam dump.
7. Related to the entry  LHO ALOG 28958, we found the shutter height was too low. The distance between the top of the shutter mirror and the beam was ~9mm. The nominal distance is 6mm. We adjusted the height of the shutter to have the nominal height. (Corey's attachment 4)