Marco Xompero – Extreme Wavefront Control Lab

ASM functionality check – part II

Oh Man! Armando and I waked up having in mind to put the hands into the ASM…. what a mess!!! So GO! light breakfast with only one egg , yogurt, cheese, ham and orange juice (for me) and double ham and cheese sandwich with tea (for armando) in order to be reactive to the ASM trickery.

After a quick meeting (2h!!!), Povilas and Dave and Jared gave us a hope: using a LEGO strategy, we would be avoiding to open the ASM on the telescope. The LEGO strategy essentially was the in-place replacement of the fiber connector. Oh yes… a bit a bet that the connector was the only source of the problem but we verified that in the mean of the replacement procedure so, all good 🙂 !

Our friends needed a bit of training but after a couple of attempts they made a great job and the electronics could communicate again with the ASM!

Armando was showing proudly the source of the issue, now harmless…

Armando shows proudly the connector now harmless

We were so happy that Alfio and I decided to celebrate with the new garlic sauce never tasted by anyone…

After to be garlic powered, we tested all the stuff and…

oh yeah! this evening we can say, it works! … (so far… of course! :))

ASM functionality checking – part I

Today we moved all the electronics in their final place with AO workstation.

After that we started testing the electronics simply switching on everything without the ASM connected in order to see if everything works or not and…

One power supply failure after switch on: red light and MasterBCU blinking

AAAAARRRGHHHH: one power supply seems not work. A strange noise like “clic-clic” at few Hertz appeared and in the meanwhile the MasterBCU is loosing power.

At this point we analyze what we knew about the status of the system:

it was kept switched off for months so an hardware piece broken is unlikely
it was perfectly working the last time in the clean room
no one touched/refurbished it
moreover the MasterBCU power supply is blinking as well.

Since we have one single phase from the three phase line supplying one single AC/DC power converter, the failure of the AC/DC power converter can be caused by something missing in the line. The MasterBCU behavior confirms that: his power come directly from the power line without passing from the AC/DC power converters.

So only one thing is really different from the clean room and the telescope…. THIS!

And here we found the problem: in the three phase wall box the NEUTRAL WAS MISSING so the system cannot work.

The telescope guys fixed it in a couple of hours and now everything works well!

The electronics now works and the MasteBCU is powered on

OK! now next step connect the ASM and we will see….!

ASM performances verification

Hi all! So at the end all the measurements are done…

First we verified the settling time of the ASM for a reduced set of modes. Here there are some examples of the step responses (the slowest mode and the most overshooting one) and a resume of the general behavior in terms of settling time:

After that we checked the ASM ability of tracking turbulence. A turbulent-like sequence of commands is sent and in the meanwhile we record the shell position using internal metrology. Here is the tracking error as a function of number of mirror modes.

Icing on the cake, we tested the FastLink connection between the NAS and the ASM (WFS Frames Counter running…):

And now we can say: ok we are ready for the Sky!

TSS fixing: the full story

The clouds went in and out with the TSS problems. AO team discovered a problem with the Thin shell Safety System (TSS) that helps the mirror against the wind effects. One crate was not applying any TSS current.

Both Microgate and Arcetri teams at this point turn the system upside down and started bravely to act on the rear of the crates…

The currents setting of the TSS where slightly decreased in order to avoid a DC DC converter to go crazy. After that a cleaning is a must.

The system were restored in the working position.

… and finally verified all good….

At this point we can say good by at our Microgate friends that are going home.

Good bye, see you!

Unpacking day 9 (bis): Not all the donuts are with a hole…

Man, the ASM seemed to work really well and the AO group continue testing the system all the day BUT at a certain point the system started whistling!!! All the actuators were disabled, the system powered off and the shell was safe against the reference body but it was still whistling at about 2 Khz!!!!

Microgate people found the problem on the TSS (Thin shell Safety System): a single crate, after a while, was not applying constantly the wind safety current and caused the shell oscillation

That crate was oscillating with few [nm] RMS movements:

On the Unpacking day 10 Microgate people will address the problem.

Sadly, Microgate people were forced to delay their flights…

…but we are happy to work again with them!