[Takahashi, Mitsuhashi]
We replaced the coil driver for the accelerometers from HPC (S1604826) to LPC (S1604764) on the 14th (Fri). The LPC was working with the low gain, but it failed (maybe due to WD) when I try to measure the TF. The FLDACC servo is turned off now.
[Takahashi, Sato]
We returned the coil driver for the accelerometers back from LPC (S1604764) to HPC (S1604826). The FLDACC servo was turned on. The servo gain for the H2 ACC was changed by -5dB.
[Takahashi, Takase]
We tried to replace the coil driver for the accelerometers from HPC (S1604826) to LPC (S1604764). The FLDACC servo could work for the H2 and H3 ACCs, but the feedback signal for the H1 ACC has been saturated. We returned the HPC.
[Takahashi, Ikeda]
We changed the coil driver for the accelerometers. The present HPCD was not replaced, but a 20dB attenuator was inserted in front of the input of the HPCD. The attenuator consists of 91kΩ resistances because of the input impedance of 10kΩ in the HPCD. Gain x10 blocks were added to the FLDACC servo to keep the open-loop gain. We confirmed the new setting can work in the ISOLATED mode.
I replaced the coil driver for the accelerometers from HPC (S1604826) to LPC (S1604764). The WD function on the LPC was disabled. The gain block was set to x35 in the FLDACC servo to keep the open-loop gain. COILOUTF were about 6000 for H1, -1600 for H2, and -3700 for H3 in count respectively.
