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MIF (ASC)
keiko.kokeyama - 17:41 Saturday 14 December 2019 (12133) Print this report
FPMI ASC efforts on Fri night
Sheila, Keiko
 
(reports on Dec 13th Night time)

Summary
In parallell where Masayuki recovered the FPMI and tried to automate the process last night, we tried to engage the ASC loops for the FPMI, however, it was not successful. Supposedly the big reason is the laser power decreased for the PRFPMI trial for a few nights ago. But not only the optical gains, the control signs seemed to flip (confirmed for DHARD_P at least). After the above efforts only for a few hours, the FPMI did not come back and the asc commissioning couldn't be continued. We left the control room at 4am. We need more time and more commissioners including for the LSC!

Additional notes
The other change since the last Saturday is that the servo filters were changed to be similar to the OLDCCTRL servos from a simple straight line integrators to aim a bit more higher bandwidths. But we don't think the new servo design could be really a problem. Note that we noticed that the suspension models (MN to TM for type-A's) in the foton filter is only a simple pendulum (f-2 above the resonance) instead of double (f-4). We are confused how they could possibly close the OLDCCTRL loops up to 4 Hz (as we hear so). Is that the approximated plant only up to the resonance? How can you go to 4Hz if so?
 
 
 
Report on Dec 13th Night time
 
While Masayuki recovered the FPMI and tried to automate last night, we tried to engage the ASC loops for the FPMI, however, it was not successful. Supposedly the big reason is the laser power decreased for the PRFPMI trial for a few nights before. But not only the optical gains, the control signs seemed to flip (confirmed for DHARD_P at least).
 
The other change since the last Saturday is that the servo filters were changed to be similar to the OLDCCTRL servos from a simple straight line integrators to aim a bit more higher bandwidths. But we don't think the new servo design could be really a problem. One note is that we noticed that the suspension models (MN to TM for type-A's) in the foton filter is only a simple pendulum instead of double (MN,IM,TM). We are confused how they close the OLDCCTRL loops up to 4 Hz (as we hear so).
 
After the above efforts only for a few hours, the FPMI did not come back and the asc commissioning couldn't be continued. We need time and more commissioners including for the lsc!Sheila, Keiko
 
Report on Dec 13th Night time
 
While Masayuki recovered the FPMI and tried to automate last night, we tried to engage the ASC loops for the FPMI, however, it was not successful. Supposedly the big reason is the laser power decreased for the PRFPMI trial for a few nights before. But not only the optical gains, the control signs seemed to flip (confirmed for DHARD_P at least).
 
The other change since the last Saturday is that the servo filters were changed to be similar to the OLDCCTRL servos from a simple straight line integrators to aim a bit more higher bandwidths. But we don't think the new servo design could be really a problem. One note is that we noticed that the suspension models (MN to TM for type-A's) in the foton filter is only a simple pendulum instead of double (MN,IM,TM). We are confused how they close the OLDCCTRL loops up to 4 Hz (as we hear so).
 
After the above efforts only for a few hours, the FPMI did not come back and the asc commissioning couldn't be continued. We need time and more commissioners including for the lsc!Sheila, Keiko
 
Report on Dec 13th Night time
 
While Masayuki recovered the FPMI and tried to automate last night, we tried to engage the ASC loops for the FPMI, however, it was not successful. Supposedly the big reason is the laser power decreased for the PRFPMI trial for a few nights before. But not only the optical gains, the control signs seemed to flip (confirmed for DHARD_P at least).
 
The other change since the last Saturday is that the servo filters were changed to be similar to the OLDCCTRL servos from a simple straight line integrators to aim a bit more higher bandwidths. But we don't think the new servo design could be really a problem. One note is that we noticed that the suspension models (MN to TM for type-A's) in the foton filter is only a simple pendulum instead of double (MN,IM,TM). We are confused how they close the OLDCCTRL loops up to 4 Hz (as we hear so).
 
After the above efforts only for a few hours, the FPMI did not come back and the asc commissioning couldn't be continued. We need time and more commissioners including for the lsc!Sheila, Keiko
 
Report on Dec 13th Night time
 
While Masayuki recovered the FPMI and tried to automate last night, we tried to engage the ASC loops for the FPMI, however, it was not successful. Supposedly the big reason is the laser power decreased for the PRFPMI trial for a few nights before. But not only the optical gains, the control signs seemed to flip (confirmed for DHARD_P at least).
 
The other change since the last Saturday is that the servo filters were changed to be similar to the OLDCCTRL servos from a simple straight line integrators to aim a bit more higher bandwidths. But we don't think the new servo design could be really a problem. One note is that we noticed that the suspension models (MN to TM for type-A's) in the foton filter is only a simple pendulum instead of double (MN,IM,TM). We are confused how they close the OLDCCTRL loops up to 4 Hz (as we hear so).
 
After the above efforts only for a few hours, the FPMI did not come back and the asc commissioning couldn't be continued. We need time and more commissioners including for the lsc!
Comments to this report:
takafumi.ushiba - 17:08 Sunday 15 December 2019 (12144) Print this report

Kokeyama-san,

Probably, the word, "DC control", is not apropliate and makes some confusions.

On MN stage of type-A suspension, we have two filters, MN_OL_DAMP and MN_OL_DCCTRL.
MN_OL_DAMP filter can be used alone and the lowest UGF is 20 mHz and the highest UGF is 4 Hz when we use it alone.

On the other hand, MN_OL_DCCTRL cannot be used alone because this filter is optimized for engaging with MN_MNOLDAMP (MN_OL_DCCTRL loop is unstabe when we engage it alone).
So, we cannot say UGF of MN_OL_DCCTRL is something.

When we engage both MN_OL_DAMP and MN_DC_CTRL at the same time, the lower UGF disappears.
So, the MN_OL_DAMP with MN_OL_DCCTRL has a UGF of 4Hz.

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