LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units1 The two LBT adaptive secondary units (LBT672a, LBT672b) A. Riccardi, M. Xompero, L. Busoni, D Zanotti INAF-Osservatorio Astrofisico di Arcetri

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units2 LBT672 units in LBT 2x8.4m mirrors Each AdSec: 672 actuators 911mm diam.

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units3 LBT672 layout Hexapod Interface flange and structural support 3 cooled electronics boxes Fixed hexapod Cold-plate and actuator support Astatic levers 50mm thick Zerodur reference-plate 1.6mm thick deformable Zerodur shell Accelerometers

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units4 Current Status at Microgate premises at ADS premises

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units5 Control electronics Communication Board (1x backplane) DSP control Board (14x backplane) Reference Signal Generator Board (1x backplane) Communication Board (1x backplane) DSP control Board (14x backplane) Reference Signal Generator Board (1x backplane) Communication Board (1x backplane) DSP control Board (14x backplane) Reference Signal Generator Board (1x backplane) Communication Board (1x backplane) DSP control Board (14x backplane) Reference Signal Generator Board (1x backplane) Communication Board (1x backplane) DSP control Board (14x backplane) Reference Signal Generator Board (1x backplane) Communication Board (1x backplane) DSP control Board (14x backplane) Reference Signal Generator Board (1x backplane) Liquid cooled crates, each comprehending 2 backplanes (3x) Distribution boards Actuators Gap Thin mirror Reference signal Power ± 48V, 35 A Real time comm link 2.9 Gbit/s Daisy chain connection DSP control Board (14x backplane) Coil 3 cooled electronics boxes 2 crates/box 84 custom DSP boards 2 DSP/board - 8 acts/board 32-bit floating-point 470Mmac/s 78 Gmac/s parallel computer -> WF reconstructor 5.3 GB internal memory for diagnostic data storage (1.8min history at 1kHz) Gigabit Ethernet Switch Diagnostic communication link To the AO supervisor 300Mbit/s

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units6 LBT672 connections within FLAO spider-arm rack Tel. power TCS AO SupervisorTCS BCU of W-unit LBT672 crates Hexapod RT comm Conf/diag comm Power Lines Acceler.(500Hz) WFS data (max 1kHz) Fast diag. m,p,f,etc( ~ 100Hz) Slow diag. T,V,etc ( ~ 1Hz) Mode to offload and alert level

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units7 LBT672 with multiple AO systems Tel. power TCS AO Supervisor TCS BCU of W-unit spider-arm rack LBT672 crates Hexapod BCU of LBTI BCU of NIRVANA AO-selector BCU RT comm Conf/diag comm Power Lines

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units8 LBT672 as finite state machine See CAN 486f007 and Lorenzo’s presentation

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units9 LBT672 in the FLAO SW structure AOSupervisor Adaptive Secondary Mirror A0Arbitrator Wavefront Sensor IDL CORE IDL Ctrl AdsecArb WFSArb AOS … … PSF OSS … MirrDiag HARDWARE FIRMWARE TCS WFSDiag HARDWARE FIRMWARE HW Ctrl See Xompero See Busoni RT comm

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units10 Control electronics as WF Reconstructor Real-time reconstructor on-board: –W slopes modal reconstruction and filtering in <50us: m t =A 0 s t +…+A n s t-n -B 1  t-1 …B m  t-m Moreover: –Mode to actuator command computation: c=Mm –Actuator force computation –Actual position and force at steady state for each command step (mean and rms value) All above data are stored at 1kHz in circular buffers in the internal memory for diagnostics (1.8min before wrap- around of buffers) AOSupervisor downloads the stored diagnostic data with decimation (~100Hz) to check behavior of AO loop and dangerous status of shell

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units11 Diagnostics in seeing limited mode In fixed (seeing limited) mode or when the loop is temporary opened a zero delta command is internally generated and triggered in order to keep the diagnostics running

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units12 Safety of the shall Hardware protection (<1ms response time) –Coils switched off when global power of actuator current driver goes beyond a user defined threshold Software protection (1kHz) at firmware level. WFS slope vector is not applied when (notified to AOSupervisor): –Modes or delta_modes exceed a user defined threshold –Same for actuator commands and delta_commands –Same for actuator forces Software protection (5-10Hz). Coil switched off(?) when: –Max tensile stress is beyond a user define threshold (computed from FEA model) Shall is fragile! Needs diagnostics continuously run

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units13 Accelerometers issue Accelerometer signals are sampled by AdSec control electronics and TT is computed (~500Hz) Accelerometers have been designed for AdSec internal use. No full rate signal exportation (telemetry?) is currently possible. Decimation? Only spectral features? TBD TT signal from accelerometers is used as open-loop command for the tilt shell (added to optical tip-tilt WFS signal) As usual, Open Loop signals are affected by severe calibration issues. The level of effectiveness of the correction has not been tested yet.

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units14 Chopping issues Chopping sync/trigger signal is not yet defined Measurements on P45 give: 5Hz with 90% duty cycle, but… Do not expect same AO settling time as for W: –5as PtV (±2.5as): 90um largest actuator gap: 30um capsens blind region+10um AO stroke+50um Chop –W operates with 70um gap: we measured <1ms settling time –At 100um gap we measured 1.7ms settling time

LBT SW workshop. Tucson, 2-6 Oct 2006 A. Riccardi - The LBT AdsSec units15 See more in the following presentations See more details on AdSec functionality (in terms of finite state machine) from Lorenzo’s presentation See more details on AdSec diagnostics software implementation from Lorenzo’s presentation See more details on AdSec configuration, calibration and setting software from Marco’s presentation