GoetzFIELDS iCDR - TDS Solar Probe Plus - FIELDS Instrument CDR Time Domain Sampler TDS Keith Goetz University of Minnesota 1

GoetzFIELDS iCDR - TDS Agenda Science Changes Performance Requirements Block Diagram(s) Design Description & Specifications Resources Breadboard/Engineering Model Testing Parts & Materials Verification Plans Peer Reviews Schedule & Open Work Issues 2

GoetzFIELDS iCDR - TDS Time Domain Sampler - Science Time Domain Sampler (TDS) is based on previous instruments –Based most recently on STEREO instrument Gathers impulsive events – voltage as a function of time –Centered peaks –Simultaneous sampling on all channels –Fixed sampling rate – 1.92MSa/s which is ~160Mb/s 24x7 throughput –Programmable effective sampling rate –Programmable event duration Events have peaks - triggered –After that, flight software scores event based on programmable criteria –Quality can be adjusted – up or down - after the fact –When telemetry is available (nominally to DCB), best event is sent –When memory is needed (for a new event), worst event is deleted Event selection can be based on quality or not – honesty –Delivered bit-rate is highly programmable – nominally 10kb/s Low rate stream gives peak activity as a function of time 3

GoetzFIELDS iCDR - TDS STEREO snapshot 4

GoetzFIELDS iCDR - TDS STEREO snapshots 5 Burst Activity

GoetzFIELDS iCDR - TDS Dust 6

GoetzFIELDS iCDR - TDS Big Dust 7

GoetzFIELDS iCDR - TDS Waveform and Particles 8 Samples Δ t = 500ns CLK ~2MHz V(t) Δ t = 500ns count(t)

GoetzFIELDS iCDR - TDS Waves and Particles 9 Samples Δ t = 500ns V(t) Δ t = 500ns count(t) t = 1,500nst = 2,000nst = 2,500nst = 3,000nst = 3,500nst = 4,000nst = 4,500nst = 5,000ns V = 0mVV = -2mVV = -4mVV = +5mVV = -12mVV = -15mVV = -10mVV = -5mV n = 2n = 4n = 2 n = 7n = 3n = 5

GoetzFIELDS iCDR - TDS TDS Heritage Time Domain Sampler (TDS) is based on STEREO instrument –The first instrument fully integrated on both spacecraft and the only instrument never to come off Changes – Science – close to the sun –Plasma frequency up from 10’s to 100’s of kHz – shock time scales are faster –TDS samples at ~2MSa/s and ~1MHz Nyquist Programmable down-sampling –Continuous sampling – reduced power supply load variations –Direct deposit – increases duty cycle – eliminates event length limit –Wave-particle correlation with SWEAP 10

GoetzFIELDS iCDR - TDS Time Domain Sampler – FIELDS2 Part of increased FIELDS reliability, TDS has DPU-like functions –Center of FIELDS2 –TM/TC Interface to S/C –Handles some FIELDS subsystems MAGi, AEB2, LNPS2 SWEAP –Interface to FIELDS1/DCB for TM/TC and timing synchronization –Interface to SWEAP for wave particle correlation, communications and timing Similar functionality in STEREO instrument –Multiple instruments –S/C TM/TC interface 11

GoetzFIELDS iCDR - TDS TDS Changes Since iPDR LVDS protection added to S/C interfaces Eliminated in-flight E-parallel measurement –Simplified in-flight calculations –To be done on the ground LVDS protection added to SWEAP interface –A new PAY requirement is coming soon 12

GoetzFIELDS iCDR - TDS TDS Requirements 13 TDS-01 Mission Length –TDS Components shall be selected to withstand the environment of SPP for the duration of the extended mission (possible launch delay). TDS-02 Spacecraft Interface Compliance (General) –TDS shall implement the spacecraft interface protocol… TDS-03 Timing from S/C –TDS shall provide latching facility upon detection of the "Virtual 1PPS" S/C timing signal… TDS-04 –Timing from DCB TDS shall provide an electrical interface to the Data Control Board capable of…

GoetzFIELDS iCDR - TDS SWEAP Requirements 14 TDS-05 SWEAP Interface - CDI –TDS shall provide an electrical interface to the SWEAP instrument capable of sending CDI commands, receiving CDI messages: [a] sending Command/Data Interface (CDI) messages to SWEAP; [b] receiving SWEAP status and burst information from SWEAP; [c] sending TDS time-keeping information; [d] sending TDS clock synchronization. TDS-06 SWEAP Interface – Particles –TDS shall provide an electrical interface to the SWEAP instrument capable of: [a] receiving particle count information from SWEAP [b] receiving particle synchronization and state information from SWEAP TDS-17 SWEAP Interface – Do no harm –TDS shall provide protection in the LVDS interfaces to/from the SWEAP instrument so as to avoid allowing a single TDS failure to damage SWEAP.

GoetzFIELDS iCDR - TDS MAG Requirements 15 TDS-07 MAG Interface – CDI –TDS shall provide an electrical interface to the MAG Electronics capable of: [a] setting control registers [b] receiving MAG Science and Engineering data [c] provide MAG AC heater synchronization

GoetzFIELDS iCDR - TDS AEB Requirements TDS-08 Antenna Electronics Board Interface (AEB) –TDS shall provide an electrical interface to the Antenna Electronics Board capable of: [a] setting Biasing D/A converters and relays [b] reading back the biasing voltages [c] provide DC-DC converter synchronization 16

GoetzFIELDS iCDR - TDS LNPS Requirements TDS-09 Low Noise Power Supply Interface (LNPS) –TDS shall provide an electrical interface to the Low Noise Power Supply capable of [a] setting control registers for Power Control and Housekeeping Channel [b] receiving an analog housekeeping signal [c] provide DC-DC synchronization 17

GoetzFIELDS iCDR - TDS TDS Requirements TDS-10 Time Domain Sampler Control –TDS shall provide electrical interfaces to the Time Domain Sampler data acquisition system capable of: [a] setting TDS instrument modes [b] receiving TDS instrument data TDS-11 TDS Memory Management –TDS shall include memory such that: [a] is capable of storing ~20 TDS snapshot events [b] allows best available event to be sent to telemetry TDS-12 TDS Instrument Calibration –TDS analog science and analog housekeeping conversion coefficients shall be determined and provided prior to S/C Integration to include gain, phase and timing 18

GoetzFIELDS iCDR - TDS Science Requirements TDS-13 E Signals –TDS shall provide an electrical interface capable of: [a] signal processing and measurement of the low frequency component of E-Field signals TDS-14 E Signals –TDS shall provide an electrical interface capable of: [a] signal processing and measurement of the AC or plasma frequency (ranging to ~1MHz) component of E-Field signals." TDS-15 B Signals –TDS shall provide an electrical interface capable of: [a] signal processing and measurement of the AC or plasma frequency (ranging to ~1MHz) component of B-Field signals (single axis)." TDS-16 Instrument Calibration –TDS shall provide calibration parameters and algorithms so as to allow conversion from telemetry units to physical units (gain and offset per channel) prior to S/C Integration. 19

GoetzFIELDS iCDR - TDS FIELDS block diagram 20

GoetzFIELDS iCDR - TDS TDS Block Diagram 21

GoetzFIELDS iCDR - TDS TDS Block Diagram – “DPU” additions 22

GoetzFIELDS iCDR - TDS TDS – Single Board Data Acquisition System Centers on RTAX4000 FPGA daughter board –Holds all logic, interfaces and LEON 3 processor instantiation TDS event data gathered by 16-bit ADCs at ~2MSa/s –Multiplexed 16-bit data bus Simultaneous acquisition of SWEAP particle counts TDS event data stored directly into dedicated event memory –16MB event SRAM – 8 parts – 512k by 32bits –Circular buffers Processor support –8-bit data bus Local SRAM w/ ECC Local boot PROM (some in FPGA?) Local program EEPROM S/C serial interfaces CDI interfaces to DCB, MAG, SWEAP Device interfaces – AEB, LNPS Mezzanine interface –Diagnostic UARTs 23

GoetzFIELDS iCDR - TDS TDS EM1 – top and bottom 24

GoetzFIELDS iCDR - TDS FIELDS2 25 LNPS2 MAGi AEB2

GoetzFIELDS iCDR - TDS GSEOS on the Bench – FIELDS2 26

GoetzFIELDS iCDR - TDS MAG Simulator 27

GoetzFIELDS iCDR - TDS TDS Channel 1 28

GoetzFIELDS iCDR - TDS TDS Channel 2 29

GoetzFIELDS iCDR - TDS TDS Channel 3 30

GoetzFIELDS iCDR - TDS TDS Channel 4 31

GoetzFIELDS iCDR - TDS TDS Channel 5 32

GoetzFIELDS iCDR - TDS TDS Big Screen 33

GoetzFIELDS iCDR - TDS Resources TDS mass CBE is 435g (not counting structure) with 500g NTE TDS power CBE is 2.36W secondary with 2.50W NTE –May increase on ±6V –+1.5V and +3.3V will increase when hot –Measured values as a function of temperature in TV TDS science bit-rate to DCB (flash) is ~10,000 b/s uncompressed –Highly flexible (by command) 1kbps to 100kbps 34

GoetzFIELDS iCDR - TDS Parts Parts list is complete –Most parts are ok –Some issues remain with SE issues – being worked –One part needs further testing – ADC AD7621 –De-rating worksheets are well along Selected ADC is great – but plastic – AD7621 –Astrium/ESA testing suggests we’ll be ok (only SEU/SEFI sensitive) –Beam testing planned at TAMU –Topless parts are in hand – to be attached to demo boards for the beam Test software is coming along –As a risk mitigation, an over current circuit breaker is in current design 35

GoetzFIELDS iCDR - TDS Reviews FIELDS iPDR held on November 2013 –No actions directed specifically at TDS TDS circuit, FPGA and FSW peer reviews held on 5 December 2014 –Electronics review provided 7 recommendations – 6 unique 3 are complete, 3 will be done in the near term –FPGA review provided 7 recommendations All will be completed in the near term –Flight Software review provided 7 recommendations 4 are complete and 3 will be completed in the near term FIELDS iCDR held on January

GoetzFIELDS iCDR - TDS Next Continue development work with EM1 –FPGA AEB control SWEAP interface operational –FSW –Calibrations and trimming –Closed box operations Deliver EM1 to UCB and integrate FIELDS1 with FIELDS2 –Continue with the full FIELDS level I&T at UCB –Run a full FIELDS CPT Populate a second board – EM2 (happening now) –Continue development work with EM2 at UMN Beam testing ADC Move to flight schematics, layout 37

GoetzFIELDS iCDR - TDS Conclusions TDS design is well advanced TDS EM is in great shape –Better than usual at this point (iCDR) Design meets or exceeds all requirements –Except SWEAP protection addition which will be added to FM Overall power –We’re only now getting to good power estimates for running hot Based on LASP’s testing with DFB Results are very promising – power increase when hot is less than expected LVDS protection needs to be extended to SWEAP communications TDS is on track for flight 38

GoetzFIELDS iCDR - TDS 39 Backup Slides

GoetzFIELDS iCDR - TDS Electronics Peer Review Recommendations 40 ActionNameDescriptionResponseClosed? TDS-01LF Signals to TDCNeed to decide if LF signals will go to TDS before CDRTo be done before 1 April TDS-02ADC Protection Diodes Consider protection diodes on housekeeping ADC input to stay within spec. Needs a test to verify the series resistor provides enough protection against out of range transients. Should coordinate a test between FIELDS and SWEAP To be done before 1 April TDS-03SWEAP ICD Complete updated SWEAP to FIELDS ICD including any particle pulse signal constraints. To be done before 1 April TDS-04Housekeeping ADC Supply Housekeeping ADC is powered from a different supply than the FPGA. There may be an overstress problem when one supply is active and the other is off. At the very least, series resistors should be placed on the signal lines between the FPGA and the ADC to protect each device from overcurrent. Operationally, there could be a 0.6V differential in the two "Vcc"s. This should be checked to make sure the operation is reliable. Series resistors will be installed in FM TDS-05LF Input Impedances The TDS analog LF channel inputs for the nominal V5 and optional (TDS-06) V3..4 channels have an effective input impedance of ~28-kohms to analog ground arising from the voltage divider used to bring +/- 115-V LF dynamic range down to the range needed by the TDS. This input impedance is at least a factor of 5 less than the expected impedance of all the other end users of the LF channels (AEB bias drivers; AEB FGND driver; DFB LF analog inputs) in parallel (at least 100-kohm or more), and so will add a significant load the LF preamp outputs. It's likely that this extra loading will lead to performance issues on the LF channel (distortion), and so I Recommend that the TDS team consider increasing the resistances used in the V5 input voltge divider to levels comensurate with those found on the AEB and DFB. Input impedance will be adjusted on the EM and FM models. TDS-07ADC input capacitors RE the ADC128S102: consider adding 1nF caps on all the analog inputs. This is a datasheet recommendation which was found to be necessary (learned when bringing up DCB- ETU#1). Capacitors will be added on FM.