PLATO Main Electronics Units (MEU) based on inputs from P. Plasson and the system team J. Miguel Mas-Hesse Centro de Astrobiología (CSIC-INTA)

PLATO Main Electronics Units (MEU)based on inputs from P. Plasson and the system team

J. Miguel Mas-Hesse

Centro de Astrobiología (CSIC-INTA)

PLATO Kick Off November 2010 J. Miguel Mas-Hesse 2

On-board data processing: Introduction

Stellar field PLATO image

• DPS goal: automatically process and extract accurate stellar light curves from the raw, messy CCD images.


On-board data processing: baseline concept

• The normal-telescopes onboard data processing system will be formed by:

– 4 CCD + 1 FEE per focal plane (telescope)• 32 telescopes

– 1 Data Processing Unit (DPU) per 2 focal planes• 16 DPU boards

– 4 DPUs per 1 Main Electronics Unit (MEU)• 4 MEU boxes

– 1 Instrument Control Unit (ICU) per 4 MEUs• 1 ICU (+ 1 fully redundant ICU)


On-board data processing: architecture

1 N-DPU for 2 N-cameras

F-cameras



Present MEU baseline concept:

+ 1 DPU per 2 focal planes+ 1 single DPU PSU box, external to the MEU’s

To ICU-M To ICU-R

SpW


PLATO MEU: FEE – DPU SpW link

• FEE – DPU link baseline:– 2 SpaceWire links per FEE (100 Mbps)

• Alternative:– 1 SpaceWire link per FEE (200 Mbps)

• Feasibility has to be demonstrated.

SpW 100 Mbps






PLATO MEU: operation

Window Extraction

up to 330.000 stars / 25 sec

FullimageAcquisition x 82 images / 6.25 sec

Data correction and LC extraction

Masks & window positions

updating

6.25 sec

6.25 sec

6.25 sec

5400sec

• Target count for 2 x 4 CCD per DPU (to be processed every 25 sec.):

Nominal sample 2x(110.000 stars/telescope) = 220.000 stars/DPU Extended sample (+50% margin) = 330.000

stars/DPU Background win. 2 x 400 Imagettes up to 2 x 2.000 Offset windows 2 x 2 x 4 half-row (2.255 pixels) Smearing rows 2 x 4 x 10 overscan rows

• Total memory requirement, including 50% margin on star count: 250 Mbytes per DPU


PLATO MEU: CPU load

• The CPU load has been estimated for various processors, based on current baseline for number of stars + extraction algorithms. At this phase the %CPU load should be ≤ 50%.

• The present concept seems feasible, but:– with 1 DPU/2 telescopes, no margin on star counts acceptable.

– with 1 DPU/telescope an extended sample with +50% margin in star counts could be considered, if required. .

Weighted mask photometry assumed


PLATO MEU: open points

SpaceWire

Router(M)

SpaceWire

Router(R)

Power Supply(M + R)

N-DPU #1

N-DPU #2

N-DPU #3

N-DPU #4

SpW

MEU

SpW

To redundant ICU

To main ICU

235 kbps

235 kbps

235 kbps

235 kbps

<1 Mbps

Test I/F - SpW

180 Mbps(2 x 64 x 1.4)

4 Mpx/s

SpWI/F

ADC

ADC

FEE #14510 px

4510

px

SpWI/F

ADC

ADC

FEE #24510 px

4510

px

SpWI/F

ADC

ADC

FEE #34510 px

4510

px

SpWI/F

ADC

ADC

FEE #44510 px

4510

px

Power Distribution

HK

Cmd

28 V, Cmd from S/CM + R

Backup concept:

+ 1 DPU board per telescope+ 4 DPUs per MEU+ 8 MEU More powerful, but too heavy


PLATO MEU: open points

Baseline Alternative

Number of telescopes per DPU

2 1

MEU-PSU 1 MEU-PSU box for 4 MEU boxes

4 MEU-PSU inside each MEU box

FEE / DPU number of SpaceWire links

2 SpaceWire links per FEE (100 Mbps)

1 SpaceWire links per FEE (200 Mbps)

FEE DPU image transfer mechanism and protocol

RMAP DMA transfer tables

DPU Boot mechanism Boot Software in PROM Pure RMAP hardware boot


PLATO: next steps

• The industrial MEU definition study is starting now.

• Goals: – Definition and dimensioning of the N-DPUs

• Global architecture, choice of processors, number of SpaceWire data links, location of PSUs, mass, power comsumption,…

• Trade off on algorithms potential increase of complexity

– Development of simulators/breadboards for critical interfaces

• Spacewire link FEE – DPU

Final design within mass and power budgets, but compliant with scientific requirements!

Documents

PLATO Main Electronics Units (MEU) based on inputs from P. Plasson and the system team J. Miguel Mas-Hesse Centro de Astrobiología (CSIC-INTA)