aLIGO LHO Logbook

H1 CDS

filiberto.clara@LIGO.ORG - posted 18:09, Tuesday 15 September 2015 - last comment - 20:41, Tuesday 15 September 2015(21555)

H1 End Station 2 Ethercat chassis - EY

While investigating the 2 Hz comb in DARM, Sheila and Patrick found communications errors with beckhoff at EY. The End Station 2 Ethercat chasssis was brought back to the lab for further troubleshooting. Spare unit was installed and Beckhoff computer was restarted.

While troubling shooting the unit found a bad EK1100 coupler on the third rail (left) of the chassis. Re-scanned unit and found 5 terminals all EL3104 (anaolog inputs) that were giving us errors. After re-scanning/checking internal cabling/power cycling, we were only able to reproduce 3 errors. We tried multiply times to try and reproduce all five errors, but could not. Eventually after a power cycle, all errors we had previously seen could not be reproduce. 

After multiple re-scans and power cycles with no errors showing up, we used a voltage calibrator and injected a 5V DC signal into the EL3104 terminals. It was later decided to reinstall unit back at EY.

Comments related to this report

eleanor.king@LIGO.ORG - 18:17, Tuesday 15 September 2015 (21557)

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Once we installed the spare EtherCat chassis, the ETMY ring heater was outputting less than the requested power (first plot). (H1:TCS-ETMY_RH_UPPERPOWER and H1:TCS-ETMY_RH_LOWERPOWER were 0.34 and 0.2 W respectively, instead of the requested 0.5W.) Trending the ring heater input channels showed this change happened during the chassis swap. It appears there was a 0.2W bias on H1:TCS-ETMY_RH_UPPERCURRENT and H1:TCS-ETMY_RH_LOWERCURRENT.

When we swapped the original chassis back in, the ETMYring heater output the correct power (second plot).

Images attached to this comment

patrick.thomas@LIGO.ORG - 20:41, Tuesday 15 September 2015 (21561)

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Short history:
We lost lock.
I was having trouble locking the ALS Y arm.
Sheila noticed that some of the end Y Beckhoff channels were not changing in value.
We opened up the system manager for end Y and saw that a number of the signals had errors (see attached screenshots from earlier post).
Sheila, Vern and Filiberto went to end Y to look at it.
They brought the end station 2 chassis back to the electronics lab. They swapped one of the terminals.
They put in an end station 2 chassis from H2 in its place.
We were able to relock with the spare chassis, but there were problems with the TCS ring heater.
Filiberto and I looked at the original chassis on the test system in the H2 building. We could not communicate with the right rail. Some of the terminals on the left rail had errors.
We swapped the coupler on the right rail with a spare. This fixed that problem. We finally ended up clearing the errors on the left rail through some random process that involved power cycling the chassis a couple of times.
We swapped the original chassis back in at end Y (with the mods). We had communication errors on all of the terminals for that chassis. Filiberto power cycled the chassis. One error remained. Filiberto power cycled the chassis again. The remaining error cleared.
We checked that the Beckhoff vacuum gauges were reading and that the ESD drive was still on.
We left end Y.

It seems we may have a serious issue, in that there was no indication that there was a problem with the Beckhoff system until we noticed that -some- of the channels were not changing in value. The CDS overview for Beckhoff was fine. The only indication outside of opening up the system manager was that some of the channels were not changing in value. Do we need to add diagnostic channels for each of the terminals into EPICS?