Grounding Scheme and EMC

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Grounding Scheme and EMC

• Matthias Rumitz, MPE

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Overview

• System Diagram
• Grounding / EMC Concept
• Mechanism Grounding Concept
• Detector Grounding Concept
• Example MEC Grounding
• Grounding / EMC Status

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System Diagram
FPU
CREs
LCL
Grating
OBC
MECDEC
SPU
Filters
CDMU
BOLC
BOLA
DPU
S/C
Bolos
CDMU
MECDEC
Temp.Sensors
OBC
SPU
Chopper
LCL
BlackBodies
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Grounding / EMC Concept

• Requirements of IID-A (5.10 5.14) implemented
• Distributed Single Point Grounding
• DPU, SPU, MEC secondary ground connected to S/C
• Additional EMC measures (DEC, BOLC) Isolation
  between primary and secondary power Reduced
  slope of DC/DC transformer EMI filter at DC/DC
  secondary side

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Mechanism Grounding Concept

• FPU (i.e. mechanisms)electrically connected to
  S/C reference ground
• Drive circuitsdifferential supply voltages
• Sensorsdifferential read-out
• gt no ground loops, EMI risk minimized

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Detector Grounding Concept

• FPU (i.e. detector-housing)electrically
  connected to S/C gt reference ground
• Warm Electronics (DEC1, DEC2, BOLC)secondary
  ground can be connected to S/C
• Detectors (CREs, bolometers)analog ground can
  be connected to FPU ( S/C)
• gt reference groundeither Detectors or Warm
  Electronics

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Example MEC Grounding

• Warm Interconnecting Harness shorter than 1m

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Grounding / EMC Status
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Redundancy Concept
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Purpose of Template

• Create uniform set of presentations
• Allow easy re-use of parts of presentations on
  other occasions (e.g. status report at
  FIRST/Herschel Science Team meetings)

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DPU Grounding
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SPU Grounding