Today with Fabian, Hirata-san and Terrence,
As for today the GAS Filters were not at the nominal height (0 µm).
- F0 GAS: 760 µm
- F1 GAS: 520 µm
- BF GAS: 92 µm
We decided to use the fishing rods (FR) to move each of them, but we found inconcistencies between the current position of the BF FR steps and the last time we used them. klog7266.
- F1 GAS Now: 450,000 BF Before: 550,000 steps.
- BF Now: 290,000 BF Before: -470,000 steps.
And we also moved them before that. See klog4449 and klog3583. This means we are blind for now....
We know from the klog7694, klog3350 and klog3278 that the ranges to move the Keystones using the FR are:
- F0 GAS: -2500 µm to +4900 µm (-1,400,000 to +1,400,000 steps)
- F1 GAS: -700 µm to +700 µm (-870,000 to +835,000 steps)
- BF GAS: -1000 µm to +1800 µm (-746,000 to +746,000 steps)
Since the SF has a very small range we will not move it this time and move only BF to nominal height and move F0 to compensate the height of the SF.
So now the heights and the current position of the stepper motors are:
- F0 GAS: -830um (Zeroed and then moved by -925,000 steps)
- F1 GAS: +800um (Was not moved)
- BF GAS: -9um (from 290,000 to 385,000 steps)
See figures bsbfcentering.png and bsf0f1compensation.png.
Later on we will investigate the consecuences of having a displacement in the F1 and F0, then calculate the new resonant frequency with this displacement and see if we can actually meet the requirements under this situation.
After centering BF and compensating F1 with F0, we measured TF for the GAS filtes. See figures 3, 4, 5 and 6. We found that the peaks on the SF are not clearly visible as before (bsf1november.png ). So we should investigate more here.
And finally after the IM misconnection issue was found and fixed we double checked the BS IM status and we measured the IM TFs for Long, Transv, Yaw again. See figures 7, 8 and 9.
Tomorrow we will add DC control for all 3 GAS filters in BS.
