We have notice a steady patter of IPC receive error on the LSC model for the H1:LSC-[X,Y]_TR_A_RFM signals coming from ISC EX and EY for many week. Lately with an increase in the number of ISC IPC channels this error rate has been increasing (it used to be one an hour or so).

It should be noted that these are almost always single errors, i.e. one data error in 16384 in a one second period. Very occasionally the error rate is 2.

I have just measured the number of errors over a 10 minute period for the IPC channels. The Y arm signal gave 30 errors (average of one every 20 seconds), the X arm gave 5 errors (average one every two minutes).

I have also noted that:

there are other RFM IPC channels coming from ISC end stations to LSC which don't show any errors (H1:ALS-[X,Y]_ARM_RFM).

there are the same number of IPC channels from X and Y arm, so why is the Y error rate 6 times higher?

Even at 30 errors in 10 minutes this is an error rate of 0.0003%