marc.pirello@LIGO.ORG - posted 12:59, Tuesday 02 April 2024 - last comment - 09:36, Tuesday 09 April 2024(76884)
H1:IMC-REFL_A_DEMOD_LOMON out of range
This could be a bad readback, or real, we are not sure. The signal should be 23dB, but the readback is showing 16.8dB on NDSCOPE and has been trending down for a while, it is throwing an error flag in beckhoff. This signal is located in ISC-R1 slot U16 on the left side. The LO signal is 9MHz and is fed through a delay line chassis, there are also baluns, cabling, etc... We were not able to determine the source of the readback error before noon, so this will have to wait until a maintenance window.
M. Pirello, F. Mera, D. Sigg
Measured RF power at the
The analog readback of the power detector was 5.89V at the front panel. This has been confirmed to be the same as the slow controls readback, which corresponds to 23.3dBm.
Seems like disconnecting and connecting the LO cable" fixed" the problem. Flaky cable and/or connector?