Patrick, Kiwamu

This is a follow-up work of the PSL power control rotation stage (see #8606). The punch line is that:

• The rotation stage is now functional and controllable through Beckoff.
• It is ready for the installation.

This morning, we installed a +/- 24V power supply cable to enable the relay circuits for the interlock. This power cable connects the interface box, which is currently sitting on the PSL table next to the periscope (see #8606), and a LIGO-standard power strip underneath the PSL table. I confirmed that it lighted up an LED on the front panel of the interface box. Then I connected the two-pin motor power and DB15 cables at the Beckoff chasis which had been disconnected 10 days ago (see #8593) for a safety purpose. To plug them back in, I powered off the chasis for approximately a minute. Then, I powered it up again after I plugged them.

We tested the rotation stage to see if it is functional. At the beginning, because the interlock was at the disable position (the mechanical switch was in its down position), the rotation stage didn't move at all regardless of what kind of command I sent. This is good as this is how it is supposed to be. Then we switched the interlock to the enable position by toggling the switch. This then allowed the rotation stage to move. So it is working fine and ready to go.

Note that, at the moment, the rotational stage doesn't have a waveplate in it. Plus, the stage is sitting aside the main path, so it is not going to do anything for the main beam.