[Nathan Holland, Jenne Driggers]

TL;DR

DC to 30 mHz BLRMS have been working as of 2022 - see LIGO-T2200025. These can be added to the BLRMS monitoring screen, and hopefully will be useful. They may need appropriate calibration. See attachment 1 for an example.

More Information

Historically the DC to 30mHz BLRMS did not work - they would diverge to +/- infinity after some time. This was corrected as of 2022, see LIGO-T2200025, by changing the C code in the RTCDS. This RTCDS change was approved in ECR LIGO-E2200027 and has been active for some time. One example of the relevant channels is H1:PEM-CS_SEIS_LVEA_VERTEX_X_BLRMS_0MHZ30, e.g. for the DC to 30 mHz seismic BLRMS at the LVEA along the x direction. Attachment 1 shows a 5 minute trace of the second trends for this channel.

Possibly this has been discussed in the past at the Friday SEI meetings, and no use yet, has been found for this BLRMS band. It may be interesting to properly calibrate these channels, place them on the monitoring screens, and then see if they are of use.