Dear all,

please find below a short summary of the activities of 17th on the mountain related to the AO system.

Italian people working at LBTO were:

L.Fini, M.Xompero

March 18th

Total # of person: 2

AO control SW

We discovered a few problems on high level software: the Adopt Control GUI and the AO Arbitrator must be modified so that the Adsec Power-on command is separated from mirror setting command and, conversely, the mirror RIP command is separated from Power-off command. This is necessary because in the normal operation it must be possible to put the shell in safe RIP position without switching off the power in order to prevent dew-point issues.

A few functions seems to have been disabled: e.g.: the "recover fail" function issued from the Adopt Control GUI seems to have no effect. For the AGw commissioning we are planning to use the same functionality provided by the engineering GUIs.

The Stop and SetNewInstrument commands of AOS have been modified to allow to be invoked repeatedly even when the AO system is not in use, without returning error. The previous behavior prevented the authorization and Preset of instruments.

The new version of AOS has been installed in AO2 build and was tested at the beginnig of the observing night. It doesn't prevent the authorization of instrument any longer, provided that the AO system is in STANDALONE mode. Some pronblems still remain when the AO system is in OBSERVATION mode. Although the latter condition is likely to be verified only during tests, to make the system more robust a further improvement of the internal logic is advisable.

The patched version has to be moved to the AO3 build to be ready for the AGw commissioning, which will be performed using AO3.


A number of tests at different elevations were performed: gap characterization, shell setting and flattening, dynamic performance, cooling flux verification, bias force characterization, behavior of the system during telescope slewing, high order offload algorithm. Slewing tests were performed with the AOS up and correctly providing elevation and wind speed values and corresponding overcurrent threshold and TSS activation/deactivation.

At elevations under 10 degress, the shell often goes in RIP status due to the failure of some actuators. Slewing tests have thus be limited to the range 10 to 90 degrees and 90 to 10 degrees.

The dynamic performance was tested using modal step responses analisys: the tests were not successfull at zenith because the shell would often go to RIP status apparently without relevant reasons. This may be due to the mirror cover causing some unknown effect on the capacitive sensor signals. The dinamic performances have, anyway, been tested during the optical interaction matrix acquisition and the following AO closed loop with WFS frame rate of 1000Hz on march 16th. Although this point requires further investigation, it should not affect the seeing limited mode commissioning. As consequence, we decide to stop the test for the other elevation angles.

Three actuators have been removed. This rises the number of removed actuators to 29.

We have verified that the shell can be successfully set up at various elevations (10, 20, 45, 70, 90 degrees) , but is likely to go to RIP state under 10 degrees. The flat shape was successfully applied at any elevation, but optical tests my be needed to asses the quality of the flat mirror shape.

Due to the fact that the calibration has been done at zenith using WFS, and assuming that the High Order offload algorithm is working correctly (this must be verified during the commissioning nights) the best flattening can be obtained doing the set flat operation at zenith and then moving to the requested elevation.

The quality of the flat to the different elevation and the HO algorithm performance tests can be performed as a result of AGw commissioning.

All the best

Luca, Marco

-- ArmandoRiccardi - 02 Apr 2010
Topic revision: r1 - 02 Apr 2010, ArmandoRiccardi
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