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AdV-SBE (EIB-SAS commissioning)
bulten Spinicelli Gosselin - 17:11 Tuesday 27 September 2022 (57209) Print this report
Balancing EIB bench
This night EIB controls were ringing, and also a large offset was found this morning. actuator 5 was around 8 Volt: this is the vertical actuator in the GAS spring closest to the laser bench. Two of the vertical microsprings were already at the end of the range, so I could not bring the system closer to the working point. Luckily, the people working in the laser lab could help me and remove some counterweight from the bench. It was necessary to remove a fixed counterweight from below the bench of about 1 kg; this weight was mounted in the vicinity of microspring stepper motor vert-3; the spring that was needed and was at the end of the range. a smaller weight ~ 250 gr was placed back. The set point of the bench could now be restored; simultaneously I tried to move all vertical microsprings closer to the central position of the microspring so that we have more freedom in the future.

It may be that the microsprings have to be adjusted again later, when new set points for EIB are found or when the thermal gradient introduced by working in the laser lab causes problems. I expect that it will be fine, though. The controls have offsets of about 1V now and none of the microsprings are close to the end of the range at this moment.
Comments to this report:
chiummo, Melo - 18:50 Tuesday 27 September 2022 (57210) Print this report

Upon request by Henk Jan, we removed a steel bar fixed on the bottom of EIB (1011g) close to vert3 actuator, and added instead a few bolts and nuts on the top of the bench (286g) close to the place where the steel bar was.

The thermal drift on the EIB is more likely related to the backreflected beam during the unlocked period of the IMC, the work in the laser lab for the replacement of a dead ALS photodiode was mostly carried on in the atrium. Actually, the temperature of the laser lab room itself did not experience a large excursion.

 

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