We are acquiring 4 channels in the PSL which are not required in the science frames (see E1500349). They are

• H1:PSL-OSC_PD_AMP_DC_OUT_DQ,
• H1:PSL-OSC_PD_BP_DC_OUT_DQ,
• H1:PSL-OSC_PD_INT_DC_OUT_DQ and
• H1:PSL-OSC_PD_ISO_DC_OUT_DQ.

The BP, INT and ISO channels are not connected and only AMP is actually used. For the three unused channels the filter module output gains have been set to null, so that only zeroes are getting written (and compressed away). Since we are not going to restart the PSL, the AMP channel will be acquired until the next opportunity. The old gains were:

• H1:PSL-OSC_PD_BP_DC_GAIN = 6.4E-4,
• H1:PSL-OSC_PD_INT_DC_GAIN = 6.11987E-4 and
• H1:PSL-OSC_PD_ISO_DC_GAIN = 6.75862E-4.