In alog 29940 I measured the change in alignment slider counts vs optic alignment change (on OSEMs) for all IO IMs.
I calculated and proposed new gains for the IM alignment sliders, however, today I noticed that the ratio of the current gains yaw/pitch is alomost exactly equal to my proposed gain ratio of pitch/yaw.
| pitch | yaw | ratio | |
| current | 0.212 | 0.388 | yaw/pitch = 1.83 |
| proposed | 0.089 | 0.049 | pitch/yaw = 1.82 |
This is evidence that the current gains are reversed from what was intended.
Below I show that swapping the current pitch and yaw gains gives a more consistant value for urad / slider count of about 0.045, instead of the current situation where the urad / slider count in yaw is 3x pitch. I also correct the gains to make the urad / slider count consistant and 0.050.
current alignment slider gains and urad / slider count
| gain | urad / slider count | |
| IM1 pitch slider gain - current | 0.212 | 0.023 |
| IM1 yaw slider gain - current | 0.388 | 0.085 |
current alignment slider gains - swapped
| gain | urad / slider count | |
| IM1 pitch slider gain - current | 0.212 | 0.023 |
| IM1 yaw slider gain - current | 0.388 |
0.085 |
| gain | urad / slider count | |
| IM1 pitch slider gain - current yaw gain | 0.388 | 0.046 |
| IM1 yaw slider gain - current pitch gain | 0.212 | 0.045 |
alignment slider gains corrected to give 0.050 urad / slider count
| gain | urad / slider count | |
| IM1 pitch slider gain - corrected | 0.459 | 0.050 |
| IM1 yaw slider gain - corrected | 0.230 | 0.050 |
This is how the alignment slider values would change on all IMs, if new alignment sliders gains were adopted.