[Ushiba, Yuzu]
We performed the lockloss investigation of 2024/11/04 23:29:09 JST. The main causes of the lockloss was the saturation of the OMC(K1:OMC-TRANS_DC_A_IN1_DQ). It makes the lost of the DARM feedback and the lockloss. But, the cause of the saturation of the OMC was not identified. I put some findings on the data around the lockloss time.
Date and state
- 2024/11/04 23:29:09 JST
- The previous state was OBSERVATION_WITHOUT_LINES. Now there is no label of the lockloss.
Findings on the data
- Figure
- We can see the saturation of the OMC(K1:OMC-TRANS_DC_A_IN1_DQ and K1:OMC-TRANS_DC_B_IN1_DQ) at the 80ms before the lockloss.
- After that, the DARM feedback control was lost and the power of IRX and IRY was lost.
- The cause of the saturation of the OMC was not identified.
- At the 20ms before the saturation, we can see the slow transient behavior on the OMC signal.
- We can see the saturation of the OMC(K1:OMC-TRANS_DC_A_IN1_DQ and K1:OMC-TRANS_DC_B_IN1_DQ) at the 80ms before the lockloss.
- Figure
- We can see the ~1Hz oscilation in the oplev sigals. (This issue was fixed in klog) I couldn't find the clue to connect this with the the saturation of the OMC signal.
- Figure
- We can see the amplitudes of ASC signals grow up with the time. At first, the K1:ASC-DHARD_Y_IN1_DQ and feedback signal started to increase. Secondly, the K1:ASC-DSOFT_Y_IN1_DQ and the feedback signal started to increase.
- ACC(Fig, Fig) anc MIC (Fig, Fig, Fig)
- At the 5 seconds befre the lock loss, we can see the coincident transient behavior (1~10 Hz frequency bands) on the ACC and MIC sensors located in the center area. The channel names are K1:PEM-ACC_PR_TABLE_ISS_Z_OUT_DQ K1:PEM-ACC_BS_TABLE_POP_Z_OUT_DQ K1:PEM-ACC_OMC_TABLE_AS_Z_OUT_DQ K1:PEM-MIC_IYC_FIELD_IYC_Z_OUT_DQ K1:PEM-MIC_PR_TABLE_REFL_Z_OUT_DQ K1:PEM-MIC_BS_TABLE_POS_Z_OUT_DQ K1:PEM-MIC_BS_TABLE_POP_Z_OUT_DQ K1:PEM-MIC_IYC_BOOTH_IYC_Z_OUT_DQ K1:PEM-MIC_BS_BOOTH_BS_Z_OUT_DQ K1:PEM-MIC_SR_BOOTH_SR_Z_OUT_DQ K1:PEM-MIC_MCF_TABLE_IMCREFL_Z_OUT_DQ K1:PEM-MIC_MCE_TABLE_IMCTRANS_Z_OUT_DQ K1:PEM-MIC_OMC_BOOTH_OMC_Z_OUT_DQ K1:PEM-MIC_OMC_TABLE_AS_Z_OUT_DQ K1:PEM-MIC_MCF_BOOTH_IMCREFL_Z_OUT_DQ
- I couldn't find the clue to connect this with the the saturation of the OMC signal.
