• KAGRA
• Observation
• iKAGRA
• Manual
• VIS

Mode Cleaner Suspensions

Each MC suspension has 4 coils and 2 pico-motors (pitch, yaw).

ETM

Each iKAGRA ETM suspension has 4 coils and 4 pico-motors (pitch:1-6, yaw:2-7, z:3-8, y:4-9).

If you find a problem about coil-magnet actuator, please check 2 things.

1. Coil drivers in particular for Y-end had a loose connection with power line (-18V, -15V).

Please check the LED on coil driver. If the LED is out, try to fasten the power line.

2. Sometimes watchdog? system stop the output current from the coil driver in order to protect mechanical system.

PR3

Check the PR3 status according to the flowchart below.

Details of the check points

• Checkpoint (1): Do OSEM values stay stable within +/- 3 um?
  • The values in the circle of check point (1) at the figure above represent the OSEM input value calibrated to um and decoupled to each degree of freedom.
  • These values should not fluctuate more than 3 um during the damping servo is on. If an earthquake occurs, the value will fluctuate around 3 um. However, they should become stable within 1 min.

• Checkpoint (2): OpLev values are at the target values?

  • The values in the circle of check point (2) at the figure above represent the Oplev input value calibrated to urad.
  • In order to align the laser beam, these values are as same as the -1 x (target values) which suggested from MIF.
• Checkpoint (3): Are all the servo filters on?
  • If the servo filters are on, then the rectangular ramps are green. If off, they are red.
  • Check if the color of the all rectangular ramps, which are in the rectangle of check point (3), are same as the figure above.
• Checkpoint (4): Is the set-point and DC control set properly?
  • Click 'OL DAMP' box above 'IM TEST' box. Check the value in the 'offset' in each path, whether these values are same as the target values.
• Checkpoint (5): Do you have TM H1 input value?
  • Check the values in the rectangles of check point (5) in the figure above.
  • If the value at the right is almost half of the value at the left, it is OK. If the value at the right is close to 0, Go to Troubleshoot B.

• Checkpoint (6): Is WatchDog or DACKill tripped?

  • Check if you can see the red bars in check point (6) rectangle in the figure above.

  • If the ramp on the 'WatchDog' box is red, the WatchDog is tripped. If the ramp on the 'DACKILL IOP' box is red, the DACKill is working.

How to troubleshoot

• Troubleshoot A: Set DC control
  • Set the ramp time as 5 sec.
  • Put the target values into the offset.
• Troubleshoot B: Reboot k1pr0
  • Call Miyakawa, Kokeyama, Shoda, or Aso.
• Troubleshoot C: Recover from WD/DACKill tripping

  • Call PR3 member till PR3 guardian gets completely ready.
    If the WatchDog and DACKill is working at the same time, reset DACKill first, and then reset WatchDog.

  • If DACKill is red

    • Confirm that the Master Switch is off. You can see red bars below 'master witch' if it is off.
      Click the DACKILL IOP button, and click 'RESET'.
      If WatchDog is tripped, go to the procedure below.
      If not, go to guardian, and go initialize the state by clicking 'INIT'.

  • If WatchDog is red

    • Confirm that the Master Switch is off. You can see red bars below 'master witch' if it is off.
      If PR3 guardian is working, Master switch should be off. If not, turn the master switch off by clicking the off button,
      Click WatchDog box. After the RMS values (fluctuating values in the middle row) get smaller than the WD setup values (constant value next to the RMS values), click reset -> reset all.
      Expecting PR3 guardian is working, alignment should be recovered automatically. If not, call PR3 member.

Appendix