Adaptive Optics Electronics

MCAOMCAO

AO Module AO Module ElectronicsElectronics

Mark Hunten

May 24-25, 2001 MCAO Preliminary Design Review

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MCAOMCAOAdaptive Optics Module Adaptive Optics Module ElectronicsElectronics

The Adaptive Optics Module (AOM) Electronics can be broken into 3 major subsystems:

•LGS CCD system•Deformable Mirrors•AOM control (everything else)


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AOM control

This covers the control system for most of the AOM. The system will control:

•Source Simulators•Shutters•Main Tip/Tilt Mirror•Science Beamsplitter•Science ADC•NGS ADC

•LGS WFS Zoom•LGS WFS positioning•NGS WFS•NGS WFS Positioning•Diagnostic WFS


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MCAOMCAOAOM Motor Listing AOM Motor Listing

(slides courtesy of Corinne Boyer)(slides courtesy of Corinne Boyer)

Device Hardware

LGS simulated source array illumination

One output channel of a XVME244 output card.

LGS simulated source array position

A single DC motor with 2 limit switches: 2 outputs and 2 inputs of a XVME244 digital I/O card.

LGS simulated source array focus

A single DC servo motor: one axis of an OMS58 servo card.

NGS peripheral simulated source array illumination


NGS central simulated source array illumination



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MCAOMCAOAOM Motor Listing, cont.AOM Motor Listing, cont.

Device Hardware

NGS simulated source array position


LGS reference source array illumination


LGS reference source array position


DM0 mask A single DC motor with 2 limit switches: 2 outputs and 2 inputs of a XVME244 digital I/O card.


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Device Hardware

Inlet shutter A single DC motor with 2 limit switches: 2 outputs and 2 inputs of a XVME244 digital I/O card.

Output shutter A single DC motor with 2 limit switches: 2 outputs and 2 inputs of a XVME244 digital I/O card.

Beam splitter wheel



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Device Hardware

Science ADC position


Science ADC rotation

2 DC servo motors: 2 channels of an OMS58 servo card.

NGS ADC rotation 2 DC servo motors: 2 channels of an OMS58 servo card.

DWFS probe arm 4 DC servo motors: 4 channels of an OMS58 servo card.


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Device Hardware

Diagnostic camera mirror


LGS zoom corrector


NGS WFS probe arms


Pupil alignment mirrors

Piezzo-electric actuators: 10 output channels of a XYCOM 531 DAC.

LGS active relay elements



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AOM Motor Listing Summary

Type of control

Number of Channels

Digital Output 22

Digital Input 38

DC Servo 31

Number of Pins (includes encoders and limit switches)

400

Number of Pins for DM

~1200


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MCAOMCAOAOM Component ControllerAOM Component Controller(slide courtesy of Corinne Boyer)(slide courtesy of Corinne Boyer)

MV

ME

270

0 36

6MH

z, 6

4 M

B C

PU

Ban

com

635

tim

e bo

ard

OM

S58

mot

or c

ontr

olle

r

OM

S58

mot

or c

ontr

olle

r

OM

S58

mot

or c

ontr

olle

r

XY

CO

M 2

44 D

igita

l I/O

Control LAN

Time bus

To servo motor electronics

To switches, relays, DC motors

To slow TT mirrors

XY

CO

M53

1 D

/A b

oard

OM

S58

mot

or c

ontr

olle

rAOM VME


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MCAOMCAO

5 CCDs

Adaptive Optics Module Adaptive Optics Module ElectronicsElectronics

RTC System InterfaceThe High Voltage Amplifier (HVA) part of the system is controlled by RTC which reads the 5 CCDs, computes the corrections and then sends the corrections to the digital interface on HVA for the DMs. That interface takes the digital information and converts into analog which is then scaled to the high voltage needed to drive the DMs –> 40 to 100VDC.

RTCHVA DMs

Servo Amp T/T3 x4 APDs


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Block diagram of NGS APD WFS system.

Photons are gathered here and sent down the fibers.The APD modules register the photonsand put out TTL pulses.

We count the events with a gated counter so we can gather counts per unit time

Then we read the counters with a digital input card to the VME computer. This is used to compensate for NGS tip tilt errors


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LGS CCD system• Study was done by HIA

on low noise rapid readout CCD systems. Conclusions are presented in Appendix O.

• The system presented today has 5 80 x 80 CCDs read out at frame times of less than 1 ms.

(2 CCDs not shown for clarity)


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LGS CCD system• Proposed system uses SDSU second generation

controllers with the new high speed fiber optic links to transfer data at 12.5MPix/s.

• This system would require one interface card to reach the desired 7.5 Mpix/s rate for the 5 80x80 CCDs with <1ms readout rate.

• SDSU is presently working on a PCI version of the high speed interface card, with the desired PMC version due out soon after.

• The controller would have 10 dual video cards to read the 5 CCDs but using only one timing card to lockstep the readout. There would also be one utility card.


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Deformable Mirror Electronics

Two designs have been evaluated as possible approaches so far. Others are available.

- Xinetics high voltage amplifiers. - University of Durham high voltage

amplifiers.The approach from the University of Durham has lower power dissipation.


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AOM Power dissipationThe DMs have a drive system that is different than what we are used to. There is a quiescent power dissipation which depends on the Iq of the high voltage amps. Example:

-Xinetics uses an amplifier that has 25 mA Iq. This, times the number of channels (1058) gives us just over 2kW of power while it is sitting there. This goes up when we move at higher frequencies. If we reduce this to 2.5 mA, the power goes down by a factor of 10. This is the main heat source for MCAO.

The rest of the electronics is estimated to dissipate 1kW. The worst case total would be over 3kW.


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AOM Space UsageThe volume of the DM system is 5 9U racks. Two each for the larger DMs and one for the smaller. Power supplies are in addition to this.The 2 VME racks take 9U each. A network interface takes 2UThe rest of the system is made mostly of 3U racks.

1 - APD Interface rack 2 - Piezo servo racks2 - DC Servo racks 1 - DC control

rack- The total space available is 111U. - We are using 100U (1U = 1.75” – don’t ask)


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MCAOMCAOAOM Electronics Mass EstimateAOM Electronics Mass Estimate

Item Qty Mass ea in kg Total mass in kgAPD Modules 12 0.25 3APD Power supply +12V\+5V\-12V 15A@+5V 1 5 5DC Servo Amp 26 0.35 9.1Piezo Amp 10 0.35 3.5DC Servo Amp P/S ?A@+24VDC/AC 2 2 4Piezo Amp P/S 20A@24VDC 1 2 23U racks for amps 3 0.5 1.5SDSU Power Supplies 3 2 6SDSU Shoeboxes 3 6 18DM Racks 5 25 125VME Rack 1 10 10Network Hub and annex 1 2 2DM LVPS + racks 3 4 12DM HVPS + racks 3 2 6

000

Total Mass: 207.1

MCAOMCAO

Design Proposal for Design Proposal for Gemini South Adaptive OpticsGemini South Adaptive Optics

PaulPaul ClarkClark


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MCAOMCAOSystem OverviewSystem Overview

• Compact, scalable design• Based on existing, proven equipment• Incorporates DAC interface, DAC and HV

amplifier cards• Total volume 45U 19” rack space (excluding

power supplies and ventilation)• Heat load 820W (approx)


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MCAOMCAO

Drive System Architectural Drive System Architectural OverviewOverview


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MCAOMCAO

DAC Interface

DAC Card

HV AmplifierHV PSU

Existing 97 actuator drive Existing 97 actuator drive systemsystem


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MCAOMCAOExisting 25 channel HV amplifier Existing 25 channel HV amplifier

cardcard(one channel populated)(one channel populated)


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MCAOMCAOPDR AgendaPDR Agenda

Thursday, 5/240800 Welcome 0805 Project overview 0830 Science case0930 Break0945 System overview1015 System modeling1100 AO Module optics1145 Lunch

1245 AO Module mechanics1340 AO Module electronics1400 Break1415 Beam Transfer Optics1510 Laser Launch

Telescope1545 Closed committee

session1800 Adjourn

Documents

Adaptive Optics Electronics