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Herschel and HIFI

Herschel and HIFI. Cryostat lid. Baffle. PACS. SPIRE. HIFI. FIRST optical bench. Today’s topics. Instrument control in general Spectrometer control + science Tuning. HIFI mode-transitions. HIFI intermediate > standby.

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Herschel and HIFI

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  1. Herschel and HIFI Cryostat lid Baffle PACS SPIRE HIFI FIRST optical bench Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  2. Today’s topics • Instrument control in general • Spectrometer control + science • Tuning Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  3. HIFI mode-transitions Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  4. HIFI intermediate > standby For each subsystem to be switched on the following steps shall be taken: 1) Notify HICU that subsystem will be switched on in 1 s. (Use type 8 to pass parameter.) 2) Switch subsystem on • To ICU instrument status changes to 48 • To PDU: switch on LCU • To ICU instrument status changes to 56 • To PDU: switch on WBS-V • To ICU instrument status changes to 60 • To PDU: switch on WBS-H • To ICU instrument status changes to 62 • To PDU: switch on HRS-V • To ICU instrument status changes to 63 • To PDU: switch on HRS-H Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  5. Configure subsystems Configuration of subsystems: 1: Table with fixed number of command is kept on-board 2: Table is edited. Only variable parts of the table are uplinked in TC-packet. This may be 8, 16 or 32 bits 3: Table is written on the LS=bus at fixed rate. Example: Configure WBS-H: Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  6. Observation philosophy • No history assumed. Each observation starts with complete configuration. • One command specifies complete observation of fixed length Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  7. HIFI OBS: command parameters • Slow or fast modulation or full power • Frequency switch or beam switch • Number of HRS per WBS • Duration of WBS • Number of modulations per packet • Number of packets • Selection of memory banks Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  8. HIFI OBS: Spectrometer control hrs hrs hrs hrs hrs hrs wbs wbs modulation HRS-period in range 0.1-2 s WBS-period in range 1-80 s Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  9. HIFI OBS: buffer overview Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  10. Science data arrays WBS Note: In principle, WBS data can be written into one more-dimensional array. In may be more efficient to write into several arrays Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  11. WBS packets Start frame contains * echo of command parameters * Integrated counter * 16 Integrated dark pixels Each science packet contains: * Number of words in packet * Word number of first word * data Packetize WBS integration buffer * User specifies ranges * User specifies word size (16/24) Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  12. Science data arrays HRS Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  13. HRS packets Packetize HRS integration buffer * User specifies which block * User specifies right shift Start frame contains * echo of command parameters * Merged HK (words 1+258n, 2+258n, 3+258n Science report contains: * Number of words in packet * Word number of first word * Right-shifted data Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

  14. Herschel-Planck datarates Other systems Prime Instrument * max 25 TM/s * max 200 kbps SC mass memory * 140 kbps over 24h ( 3 instruments) “24-h “24-h” 1.5 Mbps during 3h of contact (typ 2h20min) 2*12.5Gbits (EOL) Ground Luc Dubbeldam HIFI OBS presentation Nov 26, 2002

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