Displaying report 1-1 of 1.
Reports until 08:45, Tuesday 16 May 2023
H1 CDS (DetChar, ISC, OpsInfo)
jeffrey.kissel@LIGO.ORG - posted 08:45, Tuesday 16 May 2023 - last comment - 15:50, Tuesday 16 May 2023(69631)
Prep for Today's DC Power Supply Work 
D. Barker, C. Gray, J. Kissel, B. Weaver, T. Shaffer

In order to prepare for the work Marc & co. are doing today re-organizing the DC power supplies to the ISC and SQZ racks work permit (WP 11193), we thought hard about the racks and subsystems impacted by that work. As such, we've taken the following actions (in the order listed):

- IMC -- was locked, un-managed the IMC_LOCK guardian, and brought the state request to OFFLINE.

- Filter Cavity -- was locked on green, brought the SQZ manager to DOWN

- The following computer systems for ISC models are using ADCs and DACs from the similarly named IO chassis are powered by the power supplies in the WP -- including even some (again, but not all) CHANS_NOT_MON, 
    :: h1iopomc0    >> This IO chassis is in rack SQZ-C1, whose +24V power is going to be changed to be supplied by a different power supply (needed due to actions 3 and 7 listed in WP)
        - h1omc
        - h1omcpi

    :: h1lsc0       >> This IO chassis is in rack ISC-C1, whose faulty -18V power supply is going to be replaced (needed due to action 8 listed in WP)
        - h1lsc
        - h1lscaux
        - h1sqz
        - h1ascsqzfc

    :: h1asc0       >> this IO chassis is in rack ISC-C1, whose faulty -18V power supply is going to be replaced (needed due to action 8 listed in WP)
        - h1asc
        - h1imcasc
        - h1ascsqzifo

So,
- we browsed through (though did not peruse) the SDF systems for the above listed models, confirmed that there were no SDF diffs for these model's monitored signals (and even some). Didn't find any, but accepted the unmonitored, guardian controlled, signals for the h1omc just so we start from a better place (e.g. the DARM offset was set at -42 rather than the modern 9.7).

- Finally, we asked Dave to power down these IO chassis safely by first removing them from the Dolphin Network, and then shutting down all the front-end processes, and he has now done so (see LHO:69630).

We're ready for ISC rack power supply work!!
Comments related to this report
jeffrey.kissel@LIGO.ORG - 10:12, Tuesday 16 May 2023 (69633)CDS, DetChar, IOO, ISC, OpsInfo, SQZ
Link 

WP 11193

The primary motivation for today's work is to truly isolate the DC power supply for new, segregated h1omc0 IO chassis that houses only the new 524 kHz low-noise ADC which reads out the OMC DCPDs -- i.e *the* DARM gravitational wave sensors -- from known loud RF source generators, like Bekchoff chassis and the RF distribution system. That rack, SQZ-C1, had been powered by a cobbled together mish-mash of available DC power supplies in the DC power rack H1-VDC-C2, which powers lots of other things including RF sources, which -- we suppose -- are polluting and down-converting the OMC DCPD (the DARM) sensitivity. So, technically, you might say this work falls under the scope of ECR E2200441, and IIET Ticket 25756. This covers actions 1, 2, 3, and 4 below.

The secondary motivation is to continue the campaign of replacing ailing and failing power supplies.

I'll leave it to Marc to aLOG what actually happens today (cite the old addage "plans are out of date as soon as you make them"), but for historical reference, here's the list of changes he's planning on doing plus some context as I understand it, and a gathering place for all of the drawings and serial numbers involved.


    Actions: 
    * This swap is to keep the SQZ and ISC supplies grouped together. 
        1 - Add a +/-24V tap to the C4 junction box above H1-ISC-C4, connect tap to internal +/-24V source.                 # Impact: TEMPORARY BAD: ISC-C4 must get powered down, GOOD: segregating the h1omc0 
                                                                                                                            #         IO chassis power (in SQZ-C1) from RF distribution system, less lines in DARM

        2 - Move +/-24V sequencer cable from C3 junction box to new C4 junction box +/-24V.                                 # Impact: TEMPORARY BAD: ISC-C3 must get powered down, GOOD: segregating the h1omc0 
                                                                                                                            #         IO chassis power (in SQZ-C1) from RF distribution system, less lines in DARM

        3 - Move H1-SQZ-C1 cable in H1-VDC-C2 Power Rack from U26 to U34 RHS, set U34 RHS Kepco to +24V.                    # Impact: TEMPORARY BAD: SQZ-C1 must get powered down, h1omc0 IO chassis must get 
                                                                                                                            #         powered OFF, GOOD: h1omc0 IO chassis gets this dedicated power supply, less lines in DARM

        7 - Install new power run from H1-VDC-C2 to H1-SQZ-C1 for +24V supply for the segregated SQZ-IO [h1omc0] chassis.   # Impact: TEMPORARY BAD: SQZ-C1 must get powered down, h1omc0 IO chassis must get 
                                                                                                                            #         powered OFF, GOOD: h1omc0 IO chassis gets this dedicated power supply, less lines in DARM

    * balance load between the two Beckhoff +24V power rails 
        4 - Move H1-ISC-C3 cable in H1-VDC-C2 Power Rack from U34 to U26 RHS, set U26 RHS Kepco to +24V.                    # Impact: TEMPORARY BAD: ISC-C3 must get powered down, GOOD: as stated in Marc's work permit, 
                                                                                                                            #         balancing the DC power to Beckhoff chassis, and a cable rearrangment fall out of Action 3 above  
        5 - Move +24V H1-ISC-C3 Breakout Rail input cable to old H1-ISC-C3 +24V junction box above rack. 
        6 - Move ISC-Beckoff +24V cable from IO-ALS & IO-LSC power and to the new +24V power rail powered from H1-ISC-C3. 

    * repair failing power supply
        8 - Replace H1-ISC-C1&C2 -18V RHS with new supply.                                                                  # Impact: TEMPORARY BAD: ISC-C1 and ISC-C2 must get powered down, GOOD: noise source from failing power supply mitigated

Systems Affected: ISC-RF Generation ISC-C3 & ISC-C4 ISC-Signals Conditioning ISC-C1 & ISC-C2 ISC-Beckhoff in ISC-C3 SQZ-IO Chassis in SQZ-C1


SQZ-C1
    - Primary Functions: New home for Segregated OMC IO Chassis (and AA Chassis) and SQZ system's Beckhoff chassis
    - Wiring diagram: D1100683 for Bekchoff, New Segregated OMC IO Chassis Location Not indicated in D1900511
    - Graphical layout: D1600513 for Beckhoff, New Segregated OMC IO Chassis Location Not indicated in D1600513
    - Serial Number: S1800536

H1-VDC-C2
    - Primary Function: +/-18 and +/-24 V DC power supplies for many PSL, ISC and SQZ racks (and +/- 18 V for SUS field racks, SUS-R1, SUS-R2, SUS-R3, SUS-R4)
    - Designation of which power supply powers which rack D2300167, page 7
    - Serial Number: S1301896 

H1-ISC-C1
    - Primary functions: Audio Frequency ("Fast") Signal Conditioning for LSC and ASC IO chassis, and the IO chassis themselves
    - Wiring Diagram: D1900511, pages 1 and 2
    - Graphical layout: D1001427
    - Serial Number: S1301876

H1-ISC-C2 (Not involved in today's work)

H1-ISC-C3 
    - Primary functions: (Radio Frequency) RF distribution and CER IO Chassis Timing Fanout
    - Wiring diagram: D1900511, pages 6 and 7
    - Serial Number S1301878
    - Graphical layout: D1001427
    - Note: timing system is powered by different power supplies that the work planned today, so the work today should not impact CER timing system.  #crossfingers

H1-ISC-C4
    - Primary functions: RF generation and distribution system RF oscillators and DEMODs used by PSL, IMC, ALS, SQZ, LSC, ASC, etc.
    - Wiring diagram: D1900511, pages 8 and 9
    - Graphical layout: D1001427
    - Serial Number: S1301879
corey.gray@LIGO.ORG - 10:46, Tuesday 16 May 2023 (69638)PSL, SEI
Link

Additional Effects From This Morning's Power Supply Work For The ISC RF Racks:

  1. This RF work affected the PSL's FSS & PMC, so Jason came in to disable their locking until this RF work is complete.
  2. Since the Corner Station ISI CPS' use a timing signal from one of these RF racks, this caused all the ISI CPS' in the corner to trip.
jeffrey.kissel@LIGO.ORG - 15:50, Tuesday 16 May 2023 (69664)
Link 

See LHO:69652 for Marc's description of what was actually completed. In short, they did NOT do Actions 7 -- isolate the h1omc0 IO chassis on its own power supplies, nor did they do action 8 -- replaced the failing power supplies that support ISC-C1 and ISC-C2.
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