Reports 1-1 of 1 Clear search Modify search
VIS (PR3)
fabian.arellano - 17:22 Thursday 02 September 2021 (18108) Print this report
In-vacuum cable health check at outer side of flanges.

With Yasui-san.

We began checking whether anomalous connections of the in-vacuum cables could be detected at the outer side of the flanges. We did not finish checking. Once we finish a detailed report will be posted.

Until now we have found one problem: in the BF picomotor connector, it's not possible measure the correct capacitance between pins 1 and 6, which should be around 190 nF. This is not expected to be a problem because we tend to nerver use those picomotors.

Comments to this report:
fabian.arellano - 16:00 Friday 03 September 2021 (18134) Print this report

With Yasui-san and Hirata-san.

We finished assessing the health of the in-vacuum cables. The errors we found are the following:

  • BF picomotors:
    • Place: flange 1, connector 7.
    • Pins: 1, 6.
    • Symptom: The capacitance of the picomotor was 40 pF instead of the expected value of around 190 nF.
    • Consequence: This is not expected to be a problem. None of these picomotors controls the orientation of the IM. Actually, we never use them.
  • BF GAS LVDT:
    • Place: flange 4, connector 3.
    • Pins: 5 and chamber.
    • Symptom: A resistance value of 12.4 Ω was measured where no connection was expected.
    • Consequence: This is not expected to be a problem because pin 5 is the shield of the cable which is connected to ground when the in-air cable is connected. This symptom does not necessarily imply that the cable is damaged because the shield is exposed at the connectors and it might be simply touching the security structure.
  • TM-H4 (coil in RM):
    • Place: flange 4, connector 4.
    • Pins: 3, 5.
    • Symptom: A resistance value of 2.2 Ω was measured where no connection was expected.
    • Consequence:  This is not expected to be a problem. The actuation coil is connected to pins 2 and 7, not to 3 or 5. There is nothing connected to pin 3 and pin 5 is connected to the shield of the cable.

In the spreadsheet there are some entries with the acronym NC, which stands for no connection, and other entries with NC* with an asterisk. The astrisk indicates that we measured the resistance with LCR-9183 and not with the multimeter CD772. The multimeter can measure resistances up to 40 MΩ whereas the LCR meter can measure up to 200 MΩ. Additionally, NC* means that the measured resistances were above 100 MΩ, tyically closer to 200 MΩ,  but were not stable and were always varying. This situation is not expected to be a problem because the reistances are very high.

The only discrepancy we found in the usage of the LCR meter and the multimeter was in the measurement of the resitance between pin 2 (actuation coil) and the chamber in IM-V OSEM (flange 4, connector 1, entry shown in blue in the spreadsheet). The multimeter measured no connection, whereas the LCR meter measured 1.6 MΩ. The OSEM has been working fine, so we tend to trust the multimeter in this case. Later on the LCR meteter ran out of battery but I'm not sure it is related.

Non-image files attached to this comment
fabian.arellano - 17:54 Thursday 07 October 2021 (18497) Print this report

With Hirata-san.

We fixed problems with BF Damper LVDT cables:

  • BF-H3,
    • Place: P2-3
    • Pins: 1,6
    • Symptom: the resistance was 21.6 Ohm, which is higher than expected.
    • Solution: We identified the problem was at the pins of the white extension cable connected directly to the LVDT.  When we moved it, the resistance changed by relatively large amounts. Hirata-san removed the problematic pins, put new ones and the resistance became stable with a value of 11.46 Ohm.
  • BF-V3
    • Place: P2-1
    • Pins: 1,6
    • Symptom: the resistance was 14.1 Ohm, which is slighly higher than the expected ~ 11 Ohm.
    • Solution: We identified a problem in a connector. When we moved it, the resistance changed by non-negligible amounts. Hirata-san removed the problematic pins and put new ones and the resistance became stable. However, its value remained at around 14.13 Ohm. This might not be a problem, but we will watch it in case glitches appear.
fabian.arellano - 16:00 Thursday 04 November 2021 (18776) Print this report

With Hirata-san and Yasui-san.

  • Hirata-san and Yasui-san replaced the old hand made fragile flip cable adapters outside of the flanges with new robust ones.
  • Then we measured resistances, inductances and capacitances of the suspension components with the new flip adapters installed. See the spreadsheet.
  • Comments on the spreadsheet content will follow.
Non-image files attached to this comment
fabian.arellano - 21:04 Thursday 27 January 2022 (19604) Print this report

With Hirata-san.

Summary: We checked the cable problems reported in klog 19501. All the cables of the suspension seem to be in good condition now.

  • BF V3 LVDT: the problem was solved on the 7th of October 2021 and reported in klog 18497, so we didn't examine the cable.
  • Traverser R2 cable: we measured again the resistances that were too high, and we obtained the expected values. Likely, there was an error in measuring them before, so we didn't do anything else.
  • Traverser R1 cable: We measured again the resistances that were too high. For some of them, we got the expected values, but for some others, we corroborated the values were too high. We identified the origin of the malfunction in the in-vacuum connector that connects to the flange. Touching the cables changed some resistance values by a lot. We removed the cable and Hirata-san crimped all the pins again. This solved the problem.

I attached the compilation of the related information of all PR suspensions with the updated values for PR3.

Non-image files attached to this comment
Search Help
×

Warning

×