aLIGO LHO Logbook

H1 SPI (CDS)

jeffrey.kissel@LIGO.ORG - posted 15:43, Wednesday 08 April 2026 - last comment - 16:11, Wednesday 08 April 2026(89825)

SPI Cable Installation Status: Essentially Ready to Go

F. Clara, M. Pirello, J. Kissel
D2400111
G2401479

Fil and Marc have been doing the bulk of the work installing the diversity of cabling for SPI, as governed by D2400111 (and aided by slides in G2401479). What they started in LHO:89641 they've continued to the point of "we're as ready as we can be before we get the last of the electronics from the optics lab."

Here're some pictures of the status as of this afternoon. I'll attach them as comments to group them into a more digestible format.

A further step we can and will take in the coming days is to set up and power-budget the RF signal chain up to the point of the double mixer chassis, since this is not needed for the remaining optics-lab testing of the ISIK transceiver (which now must be redesigned; see E2600106).

Comments related to this report

jeffrey.kissel@LIGO.ORG - 15:52, Wednesday 08 April 2026 (89826)CDS

Link

Pictures of the RF delivery of 80 (or 10) MHz from ISC-C3 remote CER rack to SUS-R2 field rack by HAM3.

2026-04-08_SPIElectronics_ISC-C3_RF_PatchPanel_01.jpg 
Front of patch panel in ISC-C3 U36-U37, which where SPI 80 (or 10) MHz is sent out to the floor on port 4 (marked in the picture as "SPI").

2026-04-08_SPIElectronics_ISC-C3_to_SUS-R2_HeliaxCable_Name.jpg
The heliax cable in between the patch panels has a temporary name "SPI_CABLE_1." 
In the current version of the wiring diagram (D2400111-v6), this is called "SPI_RFDist_002," but that was merely an uninformed place-holder name.
This will be augmented both in reality and in the wiring diagram to be what's on the sticky-note to better match existing cable naming convention, "H1:SPI_C3_R2_002."

2026-04-08_SPIElectronics_SUS-R2_RFPatchPanel_Back.jpg
Heliax as it arrives at back the SUS-R2 U41-U40 patch panel.

2026-04-08_SPIElectronics_SUS-R2_RFPatchPanel_Front.jpg
Port 1 (furthest left as you look at the rack) will be live with 80 (or 10) MHz.

Images attached to this comment

jeffrey.kissel@LIGO.ORG - 15:58, Wednesday 08 April 2026 (89827)

Link

ISIJ Field Cables

2026-04-08_SPIElectronics_SUS-R1_ForISIJ_Cables_01.jpg 
Shows both cables 
- SPI_HAM2_009 ISIJ's QPDA "from HAM2 feedthrough to Variant 1 TIA" D25 cable lying on top of that S2500711 chassis installed last week into SUS-R1 U3 (LHO:89752).
- SPI_HAM2_010 ISIJ's QPDA "from Variant 1 TIA to CER SEI-C2 U27" long cable run, velco strapped to the adjacent waterfall cable tray.

2026-04-08_SPIElectronics_SUS-R1_ForISIJ_Cables_02.jpg
Just a different view of the same TIA in SUS-R1 U3.

Images attached to this comment

jeffrey.kissel@LIGO.ORG - 16:04, Wednesday 08 April 2026 (89828)

Link

ISIK Field Cables

2026-04-08_SPIElectronics_SUS-R2_ISIK_Cables.jpg
All audio-frequency SPI cables that go to-and-from SUS-R2.

- SPI_RFDist_006 delivering 4096 Hz via D9 cable to SUS-R2.
- SPI_HAM3_015 that will take all ISIK PD signals from HAM3 chamber feedthru to TIAs in SUS-R2 
- SPI_HAM3_017 and SPI_HAM2_018 that will ISIK's PDs from Variant 2 S2500712 and Variant 3 S2500713 TIAs to SEI-C2 AA/ADC channels.

Images attached to this comment

jeffrey.kissel@LIGO.ORG - 16:06, Wednesday 08 April 2026 (89829)

Link

ISIK Picomotor Control Cables

Pictures of TCSY Table, upon which an 8CH picomotor controller lives, that has a spare D25 output (CHs 5-8). This will get connected to SPI_HAM3_013 which goes from there to the HAM3 chamber.

Images attached to this comment

jeffrey.kissel@LIGO.ORG - 16:11, Wednesday 08 April 2026 (89830)CDS

Link

SEI-C2 ADC/DAC Cabling 

Here we show the consumption of all spare channels and ports on the h1seih23 computer's ADC3 AA, including some y-cable gymnastics to work around the personality of the SEI-C2 U27 D1000269 AA chassis.

We also see how there's another y-cable coming from the last CH13-16 port of the SEI-C2 U26 D1100202 AI chassis, to scrounge out the last two unused channels of the ISI HAM3 DAC1, with one leg of the cable needed to keep sending CH13 and 14 to the corner 3 H and V coil drivers of the ISI, and the other leg connecting to the long D9 SPI_RFDist_006 cable that sends 4096 Hz to SUS-R2.

Images attached to this comment