For some filters, the coefficients were not loaded. So I measured the OLG again (and also tuned again):

L3, L5, T2, T3, V1, Y2, Y3, Y4

Now the coefficient differences are not remain.

After the modification, I found that ETMX cannot be damped well for a long time when the suspension was kicked due to the lockloss (fig1).
Figure 2 shows the enlarged view of oscillation, which is at 1.67 Hz.
Since 1.67 Hz is close to 2nd mode of yaw and NBDAMP_L5 frequency, I checked both of them.

First, I checked MN_MNOLDAMP_Y loop to confirm the yaw loop is fine.
Figure 3 shows the OLTF of MN_MNOLDAMP_Y loop with Y1 and Y2 NBDAMP, which seems fine.
Note that MNOLDAMP_Y is designed to damp only 1st (0.3Hz) and 2nd (1.7Hz) resonances, so NBDAMP for 3rd (3.1Hz) and MNR(4.1Hz) should be turned on during the measurement to avoid kicking the resonance at high frequency.

Then, I measured OLTF of NBDAMP_L5 (fig4), which damps 1.67Hz longitudinal mode of Type-A tower.
During the measurement, I turned on MN_MNOLDAMP_Y and NBDAMP_{Y1,Y2} to avoid kicking the yaw resonances.
Since the resonant frequency of 2nd mode of yaw and tower longitudinal mode are very close, the yaw resonance is growing up during the measurement if there is no yaw damping.
This might be the reason of large peaking reported in klog36109.
Anyway, the OLTF of NBDAMP_L5 also seems fine, so I modified the ETMX guardian so that NBDAMP_L5 is engaged at LOCK_ACQUISITION state and disengaged at CARM_DOWN state (fig5 and fig6).

We performed the initial alignment for the Xarm, Yarm, OMC, and PRMI.

Xarm, Yarm, and OMC were done by the Guardian automatically, but for the PRMI, a manual tuning of the PRM pitch by Ushiba-san was necessary.

RECODE_GOOD_VALUES has been done.

We are checking why the ETMX suspsneion went to TRIPPED stat.
We found that the MN COILOUTF outputs gave high signal just before the state change.
(There was not earthquack observed.)

I found this L5 filter which is not used in the main pass was set to be ON in ENGAGE_RAPIDDAMP state.
So I comment-outed this line in the guardian.

Then, the ETMX suspension could reach the LOCK_AQUISITION state.

The error was at the CLOSE_MASTERSWITCH state.
While investigating the system in the situation, I found the NBDAMP L5 was ON.
After manually turing it OFF, the suspension was able to reach the SAFE state.

We need to check why the L5 was turned ON (while the state transition?).

After that, the suspension can not reach SAFE state as the guardian gives errors saying BF_COILOUTFs have outputs. (fig1)
It seems they have provided the very hight values from around 1/17 20:20. (They are still high values now.)

The TM oplev values are still oscilating.(fig2)

The ETMX have tripped around 3:50 on Jan 18.
It seemed MN H3 triged the tripped.
As the value was much lower than the trigged point, I reseted the WD.

There was not any earthquakes on the time?

The SR3 have tripped around 3:50 on Jan 18.
An eathquake was observed around that time.
I reset it as the values monitored by the WD looks nomal now.

(same as SRM: klog36161)

The SRM have tripped around 3:50 on Jan 18.
An eathquake was observed around that time.
I reset it as the values monitored by the WD looks nomal now.

About the ~3 Hz oscillation of the yaw during the pitch OLG measurement, Ushiba-san suggested me to apply the NBDAMP Y1 filter (3.13Hz).
I followed his suggestion and confirmed the oscillation was not occurred in the yaw.

I measured the OLG of the ITMX MNOLDAMP Filter of roll. It's coherence and phase were looked OK, but the gain was smaller than the reference, about -60dB. [Fig. 1]
At that time, the ROL oplev light was almost only in thee SEG4.

Yokozawa-san went into the mine to perform the centering, and I measured the OLG. Then the result was similer to the reference. [Fig. 2]

We changed FM5 to FM1 in the T1 loop filter. As a result, the saturation disappeared.
The values of COILOUTF are now slightly larger than they were in O4c. So we decided to keep this situation.
The TF of this T1 loop when using FM1 is the attached figure.

Even if LOCK_ACQUISITION can be kept, this issue should be solved because the output is continuously saturating.
So, some modifications of the NB DAMP T filter (and others if necessary) is necessary.

[YokozaWashimi]

We measured the OLGs of the OLDAMP filters (P, Y) at the LOCK-AQUISITION state.

We found the MN COILOUTF values are very high comparing to other suspension.
It can be caused by the loop of NBDAMP T1.
After the adjustment FM5 was used. If we use FM1 for the loop, the COILOUTF values are smaller a little.
FM5 = FM1 + 10dB.

As the suspension could be kept at LOCK_AQUISITION state for long time (>1day), I did not change it.

We measured MN OLDAMP filters.

• Red lines: today
• Blue lines: 2024/8
• Green lines: 2025/2

We measured these with LOCK_AQUISITION state.

I offloaded the F0 GAS with the FR.

[Kimura, Yasui, M. Takahashi, H. Sawada, Ohmae and Yamaguchi]
 On 15 Jan., as part of maintenance work on the cryo-cooler units, the compressor ( Yea ) for the duct shield cryo-cooler unitin the Y-end machine room was replaced.
The removed compressor was packaged for repair.
Preparatory work was performed for replacing the two failed compressors in the center machine room.
Replacement with refurbished compressors is scheduled for next week or later.
 The compressor from the Y-end machine room and the two failed compressors from the center machine room ( X-P53 and Y-P-53 ) are scheduled to be returned to the factory in February.
 The cooling water circulation system in the central machinery room has been temporarily shut down for compressor replacement work.
 Operation is scheduled to resume in early February.

[YamaT-san, Ikeda]

We created and executed the K1IZ1 model file.
The model was based on K1IX1 and modified to K1IZ1.
All RFM-related components were removed and changed to either terminate or connect to GND.

Not yet registered with the DAQ.
On the maintenance day, add all models to rtsystab and register only the Testpoint for k1iopiz1 with the master.

The following numbers were assigned for DCUID:
58: k1iopiz1
62: k1visitmzt
67: k1visitmzp
77: k1visitmzlsc
118:k1sendbeaconiz