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ISUAL Instrument Software

ISUAL Instrument Software. S. Geller. Processors Used Startup Status Telemetry Command Processing Command Echo Science Startup Mass Memory Initialization Data Compression Module Initialization Setting High Voltages Filter Wheel and Heater control. Aurora Mode Aurora Science Products

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ISUAL Instrument Software

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  1. ISUAL Instrument Software S. Geller

  2. Processors Used Startup Status Telemetry Command Processing Command Echo Science Startup Mass Memory Initialization Data Compression Module Initialization Setting High Voltages Filter Wheel and Heater control Aurora Mode Aurora Science Products Photometer Sampling Rates Camera Readouts Aurora Mode Parameters Sprite Mode Sprite Science Products Photometer Sampling Rates Camera Readouts Sprite Mode Parameters Dayside Processing Development Tools Software Testing Version Control Instrument Software Overview NCKU UCB Tohoku Instrument Software S. Geller

  3. Processors Used • DPU • 8085 processor, heritage from IMAGE/FUV • Primary purpose: Overall control and sequencing • DSP • Fast Signal Processor • Software developed by NCKU • Primary purpose: Data Compression NCKU UCB Tohoku Instrument Software S. Geller

  4. ISUAL Modes • Standby • Aurora/Airglow Observing • Sprite Observing • Dayside Data Readout NCKU UCB Tohoku Instrument Software S. Geller

  5. Startup - Power On Status • All power services off • HV values set to zero • Heaters off • Mass Memory off • DCM off • No Automatic Turn-on of Power Services NCKU UCB Tohoku Instrument Software S. Geller

  6. Power-On Telemetry • Status telemetry (SOH) generated • Command echoes • No Science TM • Command processing is active • Command echoes are generated in status telemetry • Any changes after power-on will be the result of receiving a ground command. • Time-tagged commands are stored in ordinary RAM, which means they are lost when power goes off. NCKU UCB Tohoku Instrument Software S. Geller

  7. Status Telemetry • Uses Transmit side of OBMU channel • Information sent asynchronously • SOH data is sent every 30 seconds (may be commanded to go faster). • SOH data is sent in all ISUAL modes • The spacecraft stores the SOH data between ground contacts. NCKU UCB Tohoku Instrument Software S. Geller

  8. SOH Packet • Sent as CCSDS packet • SOH Includes : • Time of housekeeping sample • ISUAL Mode • Voltages, Currents, Temperatures • Last Command • Number of commands executed • Fault Flags NCKU UCB Tohoku Instrument Software S. Geller

  9. Status Channel • Status channel is asynchronous RS-422 with average data rate of 400 bits/sec (80 bytes/sec) running at 9600 baud • Status Channel Format: • CCSDS Source Packet with Secondary Header containing Time Code (same as Science T/M Data Packets) • Trailer Byte = 0xAA • Data part of Packet includes an internal checksum NCKU UCB Tohoku Instrument Software S. Geller

  10. Command Input • Commands are generated either by the spacecraft or from Ground Station, using STOL • Command input uses receiver side of OBMU channel. Commands are received as strings of bytes, one byte per interrupt; DPU puts the bytes on a queue. • The command interpreter reads the queue, verifies checksums and sets up the commands for execution. NCKU UCB Tohoku Instrument Software S. Geller

  11. Command Types • Time, Position & Attitude (TPA) command is generated by the spacecraft (ApID=700 hex) • All other commands come from the ground; (ApID=701 hex) • Command ApIDs 700-70F are assigned to ISUAL NCKU UCB Tohoku Instrument Software S. Geller

  12. Time-Tagged Commands • All command packets have a secondary header • On Time-tagged commands, the secondary header gives the UT when the command is to be executed by ISUAL. • Commands to be executed immediately have a secondary header with first byte set to hex FF. NCKU UCB Tohoku Instrument Software S. Geller

  13. Setting ISUAL Time • The ISUAL Clock starts running with all zero time • An SOH status byte says whether time has been set. • ISUAL receives time in a Time-Position-Attitude (TPA) command. The time is effective as of the next 1-second PPS tick. • A PPS tick generates an interrupt NCKU UCB Tohoku Instrument Software S. Geller

  14. Command Echo Packet • All commands are echoed (except patch-data) • Echo is sent on the status channel whenever a command is received by ISUAL • Echoes are encapsulated in a CCSDS packet • Multiple echoes possible in one packet NCKU UCB Tohoku Instrument Software S. Geller

  15. Command Echo Data • Opcode of echoed command • Sequence number of echoed command • Exec code: • 0=executed • 1=queued (was time-tagged) • Time when executed/queued • Result code • (OK, or errors like invalid opcode) NCKU UCB Tohoku Instrument Software S. Geller

  16. NCKU UCB Tohoku Instrument Software S. Geller

  17. Standby Mode

  18. Standby Mode • All power services off (except MM and DCM) • Mass Memory and DCM may or may not be turned on. • Command processing is active • Time-tagged commands are executed on schedule • Command echoes are generated • Status (SOH) telemetry generated • No Science Telemetry is generated • Standby Mode is entered at ISUAL power-on • Standby Mode may be entered from other modes by: • I_STANDBY_SET command • I_SAFE_SET command NCKU UCB Tohoku Instrument Software S. Geller

  19. ISUAL Power-on status • Standby Mode, plus: • Mass Memory is off, DCM is off • Time-tagged command list is empty • PVCF storage is empty NCKU UCB Tohoku Instrument Software S. Geller

  20. I_STANDBY_SET command execution • Step 1 • On-going Camera and Photometer readouts are completed • Camera and Photometer data taking is terminated • Step 2 • HV power services are turned off • All other power services (except MM and DCM) are turned off • Step 3 • Attempt made to transmit accumulated Science TM data to spacecraft (even if less than a full file). This attempt may not succeed immediately. NCKU UCB Tohoku Instrument Software S. Geller

  21. I_STANDBY_SET command execution (cont.) • Final Result of command: • HV values settings are unchanged (but HV power services are off) • Stored list of time-tagged commands unchanged, continues to be processed. • No science data taking • SOH continues to be sent NCKU UCB Tohoku Instrument Software S. Geller

  22. I_SAFE_SET command execution • Immediately turn off all HV power services • Stop executing time-tagged commands, but retain the command list. • Abort Camera and Photometer data taking • Abort data compression; Turn off DCM • Abort TM generation • Turn off Mass Memory; this erases TM accumulation • Enter Standby Mode NCKU UCB Tohoku Instrument Software S. Geller

  23. Science Startup • Science modes (Aurora, Sprite) may be started when in Standby mode, before taking data • Invoked by I_SCIENCE command • I_SCIENCE not required if changing among Aurora, Sprite or Dayside modes. NCKU UCB Tohoku Instrument Software S. Geller

  24. I_SCIENCE Command • (each step checks to see if the operation has already been done) • Initialize Mass Memory • Initialize DCM • Set mode (aurora, sprite) • Initialize and start TM generation NCKU UCB Tohoku Instrument Software S. Geller

  25. Mass Memory Initialization • Turn on Mass Memory power • Memory test; update bad-memory map. • Allocate Mass Memory Control Blocks • for DCM,Camera, Spectrophotometer and Array photometer • Allocate TM area • for building packets, PVCFs and 64 Megabit “files”. NCKU UCB Tohoku Instrument Software S. Geller

  26. Data Compression Module (DCM) Initialization • Turn on DCM • DCM shows “busy” until it completes its internal checks • Copy DSP program from EEPROM to MM • Set up initial “don’t do any compression” MMCB • Issue CDI commands to tell DCM where in MM it can get its initial MMCB and DSP program NCKU UCB Tohoku Instrument Software S. Geller

  27. What is not done by I_SCIENCE • HV settings • Heater control • Filter Setting NCKU UCB Tohoku Instrument Software S. Geller

  28. Setting High Voltages • Levels are set by loading registers • HV levels not active until a particular HV power service is turned on • Commands to set HV registers must be preceded by “May-I” command, with 4 code bytes. NCKU UCB Tohoku Instrument Software S. Geller

  29. Camera HV Settings • Camera - MCP • Day • Night (Aurora) • Night (Sprites) • Camera - Phosphor • Day • Night (Aurora) • Night (Sprites) NCKU UCB Tohoku Instrument Software S. Geller

  30. Spectrophotometer HV Settings • 6 HV power supplies • Day • Night (Aurora) • Night (Sprites) • total of 6 x 3 = 18 settings NCKU UCB Tohoku Instrument Software S. Geller

  31. Array Photometer HV Settings • 2 HV power supplies • Day value • Night value • total of 2 x 2 = 4 settings • Commanded by DPU via CDI NCKU UCB Tohoku Instrument Software S. Geller

  32. HeaterControl • “Open Loop” • Table is loaded for each heater, giving: • number of seconds on • number of seconds off • Each heater can be commanded to: • Active (cycling) • Off (always off) • No synchronizing with data taking NCKU UCB Tohoku Instrument Software S. Geller

  33. Filter Wheel operation • Command: I_FILTER_SET index=n • rotate filter wheel to position n • DPU ensures that camera exposures have been paused before moving the filter wheel. • DPU selects position index, then gives a “start” • DPU determines that wheel has moved to the desired position. NCKU UCB Tohoku Instrument Software S. Geller

  34. Aurora Mode NCKU UCB Tohoku Instrument Software S. Geller

  35. Aurora Mode Setup • HV values set in registers • Heaters cycling • Initial Filter set • Do Science Setup • I_SCIENCE command, select Aurora mode NCKU UCB Tohoku Instrument Software S. Geller

  36. Aurora Science Products • Aurora Picture: • Taken at regular intervals • Fixed exposure length, filter • Spectrophotometer: • Averages of sample groups • Array Photometer: • Averages of sample groups NCKU UCB Tohoku Instrument Software S. Geller

  37. Data Compression • Normally, all science data will be compressed. • For diagnostic and perhaps other purposes uncompressed data may be sent. • Data compression may be turned on and off by command; the default is on - compressed. NCKU UCB Tohoku Instrument Software S. Geller

  38. Camera Readouts • MM-Camera interface has registers for two readout areas. • After a readout is complete, camera automatically switches to the other area for the next readout. • DPU gets an interrupt when the switch occurs. NCKU UCB Tohoku Instrument Software S. Geller

  39. Spectrophotometer • Fixed rate: 10,000 samples/sec • 6 Sensors, with separate HV settings NCKU UCB Tohoku Instrument Software S. Geller

  40. Spectrophotometer Sampling • Continuous sampling while in Aurora mode • Not synchronized to Camera exposures • N samples will be taken and stored into an MM area. • The DCM computes an average every M samples • Result is N/M groups of 6 integer values. • Typically, N=1000, M=5 NCKU UCB Tohoku Instrument Software S. Geller

  41. Spectrophotometer Readouts • Spectrophotometer fills memory with N samples, then automatically switches to a different readout area. • DPU gets an interrupt on the switch, and stores the time of the first sample of the new group. • Completed sample group goes to the DCM for averaging. NCKU UCB Tohoku Instrument Software S. Geller

  42. Array Photometer • 16 channels with one filter and HV setting • 16 channels with another filter and HV setting • Two possible sampling rates NCKU UCB Tohoku Instrument Software S. Geller

  43. Array Photometer Sampling • Sampling and averaging done the same as with the Spectrophotometer. • N and M may be different from the values set for the Spectrophotometer NCKU UCB Tohoku Instrument Software S. Geller

  44. Summary: Aurora Mode parameters • Camera • Filter • exposure length (100 ms?) • Interval between exposures (1 minute?) • Spectrophotometer N and M • Array Photometer N and M. Sample rate. NCKU UCB Tohoku Instrument Software S. Geller

  45. Aurora Mode Data Cycle • DPU starts Camera exposure at regular intervals • notes start time • waits for camera to readout exposure. • While this is going on, DPU captures samples from both Photometer units. • Data is sent to DCM • Compressed data is sent as TM packets NCKU UCB Tohoku Instrument Software S. Geller

  46. Aurora Mode Data Taking Operation Initialization Data Taking 1 2 Readout Camera; Wait until time for Set Filter send data to an image compression Setup camera Pass accumulated Start Camera parameters photometer arrays exposure to averaging Setup photometer 1 parameters. wait for exposure Start continuous to complete sampling 1 2 NCKU UCB Tohoku Instrument Software S. Geller

  47. Sprite Mode NCKU UCB Tohoku Instrument Software S. Geller

  48. Sprite Mode Setup • HV values set in registers • Heaters cycling • Initial Filter set • Set sizes of circular buffers, number of post-trigger camera frames. • Select Trigger Photometer; Set trigger level • Do Science Setup: I_SCIENCE mode= • Sprite-Burst • Sprite-Continuous NCKU UCB Tohoku Instrument Software S. Geller

  49. Camera Readouts • Camera interface has registers for two readout areas. After all the images from a Sprite event are stored in MM, the camera automatically switches to the other area to readout the next event. • DPU gets an interrupt for each Sprite Event • DPU gets a (different) interrupt for each readout switch. NCKU UCB Tohoku Instrument Software S. Geller

  50. Camera operation in Sprite Burst Mode • Until Event, do exposures; no readout • When Sprite Event happens. • Shift pre-trigger image down in CCD • Acquire Sprite image • Acquire post-trigger images in CCD • Read out the images: • 1 pre-Trigger • 1 Sprite • 6 (or less) post-Trigger NCKU UCB Tohoku Instrument Software S. Geller

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