This morning while the IFO was still locked at the begining of maintence, Richard helped me cable the REFL B9I signal to the common mode summing junction.  We plugged it into REFL B IN2, which is labeled for REFLAIR on the medm screen.  We also added a label on the cable that is the same on both ends. 

We switched the CARM loop over to REFL B without any problems, using the same gain settings as are used for REFL A.  The CARM ugf stayed at around 10kHz.  We were locked with REFL B in loop and REFL A out of loop from about 15:38 UTC until 16:15 UTC.

The attachment shows the spectrum of REFL A B with no light, with A in loop, and with B in loop.  The REFL B readback is limited by ADC noise, so by switching the CARM control to REFL B we can use REFL A with it's better whitening to get a better out of loop REFL measurement.  The DARM spectrum had many large glitches during this time because the sensor correction was off and people were working on maintence in the VEAs, so it would be worth doing this again in low noise to look at coherences with DARM.