hugh.radkins@LIGO.ORG - posted 13:17, Tuesday 05 June 2018 - last comment - 16:20, Tuesday 05 June 2018(42334)
WHAMs 5 & 6 HEPIs Unlocked
No difficulty unlocking except for the access restrictions from ISC tables and laser assemblies. Signs have been changed; please be mindful of the suspended parts.
Running Range-of-Motion tests; will report shortly.
For HAM6 X & Y motion, see the first attachment. It looks like the X motion is clear to 0.8mm but the Y direction is showing some interference around +560um and -730um. Yes this bothers me but it is more than enough range for operations.
For the Z stroke, see the second attachment. You see some separation of the local sensors around 380 microns but that does not seem as bad as the separation at -460. The platform tripped during the minus stoke and this was from the actuator drive railing. Again, more than enough range for normal operation but I should investigate and mitigate at a low priority. When Isolated, the HAMs should never move that much (except HAM1 which does have AC isolation.)
As far as the current running position relative to the long term locked position, all are within a few micro units except X which is about 9um from the locked position. Putting the isolated position at the locked position increased the output drives which we like to keep low. I doubt anyone will notice the difference between the long term locked position and the current isolated position; but, if anyone needs to shift the position, it can be done. At worst, we'll need to put some turns on the big springs.
For HAM5 see the attachments: The horizontal local sensors show near perfect overlay supporting the assessment that there is no interference. The second plot shows the verticals and it is evident that there is some interference around the -700 micron point. More than good enough for nominal operations.