david.barker@LIGO.ORG - posted 08:57, Friday 14 August 2026 (91537)
Corner Station PEM Accelerometer mismatch identified and fixed
Miranda, Dave:
Over the past week we have documented the LHO PEM accelerometers and produced an as-built wiring drawing
This was in response to a possible misreading of accelerometer(s) with the wrong channel names.
We found three accelerometers with incorrect names, which date back to pre-O4, so I'm tagging DETCHAR.
| The accelerometer | Was being readout as this channel |
| H1:PEM-CS_ACC_LVEAFLOOR_HAM6_Z_DQ | H1:PEM-CS_ACC_BEAMTUBE_SRTUBE_X_DQ |
| H1:PEM-CS_ACC_BEAMTUBE_SRTUBE_X_DQ | H1:PEM-CS_ACC_EBAY_FLOOR_Z_DQ |
| H1:PEM-CS_ACC_EBAY_FLOOR_Z_DQ | H1:PEM-CS_ACC_LVEAFLOOR_HAM6_Z_DQ |
We fixed this at 16:00 Thursday 13th August 2026 PDT by remapping the BNC connections on the front panel of APC1. The cable going to port12 was moved to port13, that going to port13 was moved to port14 and that going to port14 was moved to port12.
We tap-tested the EBAY_FLOOR accelerometer at 16:10 and this showed up on H1:PEM-CS_ACC_EBAY_FLOOR_Z_DQ