Fil removed the comparator box and ran some quick tests in the EE lab; he found nothing obviously wrong with it. The box was reinstalled without issue. Using a multimeter, Fil measured the input signal from the IR sensor. The interesting thing here is that the input signal changed depending on how the box was positioned (trip point is at ~96mV). Hanging free in mid-air the input signal measured ~56mV; with Fil touching the box, still hanging free, the signal dropped to ~36mV; holding the box on the side of the TCS enclosure the signal changed yet again to ~25mV; and finally, placing the box on top of the TCS enclosure (its usual home), the signal dropped yet again to ~15mV. There is definitely something fishy going on with this comparator box; grounding issue or cable/connection problem maybe?
As a final check I opened the side panel to the TCS enclosure to check the viewport to ensure there were no obvious signs of damage. Using a green flashlight I found no obvious signs of damage on either optic in the TCS viewport; in addition, nothing obviously looked amiss with the viewport itself, so for know now this seems to be an issue with either the comparator box or the IR sensor. Seeing as how it appears to be working again (famous last words, I know...) we restarted the TCSy CO2 laser. Everything came up without issue, we will continue to monitor this.
alastair.heptonstall@LIGO.ORG - 17:00, Wednesday 01 February 2017 (33823)
Wondering if this is related to the glitchy sigals from the TCSY laser controller. They all run through that same controller box (though of course we did try swapping that out). The lifting it up / putting it down, sounds like it could be a weird grounding issue.
Give me a call if you need any help on this tonight - I'll email my number to you.
jason.oberling@LIGO.ORG - 19:26, Wednesday 01 February 2017 (33827)TCS
Here are a couple pictures for informational purposes. The first is the TCS laser controller chassis, and shows which light is lit when the IR sensor is in alarm. The second shows the comparator box in alarm. This box sits on top of the TCSy enclosure, on the north-east corner.
J. Oberling, F. Clara
Fil removed the comparator box and ran some quick tests in the EE lab; he found nothing obviously wrong with it. The box was reinstalled without issue. Using a multimeter, Fil measured the input signal from the IR sensor. The interesting thing here is that the input signal changed depending on how the box was positioned (trip point is at ~96mV). Hanging free in mid-air the input signal measured ~56mV; with Fil touching the box, still hanging free, the signal dropped to ~36mV; holding the box on the side of the TCS enclosure the signal changed yet again to ~25mV; and finally, placing the box on top of the TCS enclosure (its usual home), the signal dropped yet again to ~15mV. There is definitely something fishy going on with this comparator box; grounding issue or cable/connection problem maybe?
As a final check I opened the side panel to the TCS enclosure to check the viewport to ensure there were no obvious signs of damage. Using a green flashlight I found no obvious signs of damage on either optic in the TCS viewport; in addition, nothing obviously looked amiss with the viewport itself, so for
knownow this seems to be an issue with either the comparator box or the IR sensor. Seeing as how it appears to be working again (famous last words, I know...) we restarted the TCSy CO2 laser. Everything came up without issue, we will continue to monitor this.Wondering if this is related to the glitchy sigals from the TCSY laser controller. They all run through that same controller box (though of course we did try swapping that out). The lifting it up / putting it down, sounds like it could be a weird grounding issue.
Give me a call if you need any help on this tonight - I'll email my number to you.
Here are a couple pictures for informational purposes. The first is the TCS laser controller chassis, and shows which light is lit when the IR sensor is in alarm. The second shows the comparator box in alarm. This box sits on top of the TCSy enclosure, on the north-east corner.