LAT EMI Test LAT test levels derived from LAT-SS-0778 Use CAL EMI test procedure as template –LAT-PS Test Suite: –CE102 Conducted Emissions, Power Leads, 10 kHz to 10 MHz, MIL-STD-462, CE03 –CECM Conducted Emissions, Time Domain, 150 MHz Bandwidth –CS102 Conducted Susceptibility, Power Leads, 10 kHz to 10 MHz, MIL-STD-462, CS02 –CSCM Conducted Susceptibility, Common Mode, 30 Hz to 150 MHz, MIL-STD-462, CS02 –CS06 Conducted Susceptibility, Spike, Power Leads, MIL-STD-462 –RE101 Radiated Emissions, Magnetic Field, 20 Hz to 50 kHz –RE102 Radiated Emissions, Electric Field, 10 kHz to 18 GHz, MIL-STD-461E –RS101 Radiated Susceptibility, Magnetic Field, 20 Hz to 50 kHz –RS103 Radiated Susceptibility, Electric Field, 30 MHz to 18 GHz

LAT Power Interfaces SC-LAT Power Interfaces –SC PRU (P) - LAT PDU –SC PRU (R) - LAT PDU –SC PRU (P) - LAT SIU (P) –SC PRU (R) - LAT SIU (R) –SC PRU (P) - LAT VCHP +Y –SC PRU (P) - LAT VCHP -Y –SC PRU (R) - LAT VCHP +Y –SC PRU (R) - LAT VCHP -Y –SC PDU (P) - LAT MAKEUP –SC PDU (R) - LAT MAKEUP

Test Limitations RS103 upper limit of 18GHz (40GHz) Limited area of RS101 test –Requires scanning each 10cm x 10cm area, ~16min/scan –~1450 scans for the LAT, another ~1200 for the radiators (~29 days) –Scan selected locations around connectors, PMTs, BEA Limited B side conducted testing –Emissions tests and susceptibility only where noted on A side Limited VCHP htr testing –Emissions only

EMI Test Configurations Split EMI test –Conducted tests performed in the high bay integration area –Radiated testing performed in anechoic chamber Conducted emissions and susceptibility tests with SIU and PDU do not require radiators, but do require good access to connectors – LAT z axis vertical to provide access to LAT connectors with 2m cable lengths

Radiated Test Configuration

LAT Cable Feedthrough

Conducted Test Considerations Fully test: –SC PRU (P) - LAT PDU –SC PRU (P) - LAT SIU (P) Limited test: –SC PRU (R) - LAT PDU –SC PRU (R) - LAT SIU (R) Need to resolve operating constraints on VCHP htrs –Can they be run for extended periods of time at ambient temp? –Thermostatic overtemp protection –Limited power, ~4W/circuit No plan to test PDU - LAT Makeup –Thermostatic control, open circuit at ambient temp Conducted susceptibility tests may require disabling bus protection unit

Conducted Test Harness Require access to power harness 2m from LAT I/F –CE102, CS102 (10kHz - 150kHz), CSCM (30Hz - 150kHz), CECM –All conductors of power circuit must be connected to a single 1/4” lug on line conditioner –All conductors must be gathered into a bundle so that a current probe may be connected around them Require access to power harness ~5cm for LAT I/F –CS102 (150kHz - 150MHz), CS06, CSCM (150kHz - 150MHz) –Small bare section of a single conductor to attach clip lead for hf injection EMI shielding not required on harnesses

Radiated Test Harness No access to conductors required Harness must be fully shielded –Includes all connector savers Any test ports must be closed out or have shielded harnesses –“back door” Test harnesses must be shielded –Accelerometers –TCs & thermistors Harness supports not directly connected to the LAT should be nonconducting material, wood or PVC

Test Software Emissions Testing –Utilize the FSW Charge Injection Calibration function to inject charge into a large number of detectors. The number of channels into which charge can be injected will be limited by: a) FSW design (which is not yet complete); and b) The number of channels which can physically be injected with charge in any given one second cycle. The one second cycle is required to provide repeatability during the Emissions frequency sweeps. Susceptibility Testing: –A variation of the test described in the End-to-End (ETE) Test Plan, LAT- MD-03489, paragraph 2.2.1, item 4, "Nominal Rate Cosmic Ray Test" will be used. This test is run at ambient temperature and at nominal voltage, timing, threshold, and trigger configurations. Both Cosmics and the external trigger function are used to create on-orbit trigger rates. The external trigger rate will be set so that the total trigger rate will be at or near the nominal expected on-orbit values. –The externally triggered events should have very low occupancy, monitor to see if occupancy goes up –The cosmic ray events should remain constant, monitor to see if rate goes up.

Test EGSE Software Tools Displays of natural trigger rates and occupancy of externally triggered events should be strip chart type Other error status, checksum, etc. should latch

RE102 - Integrated LAT

RE101 – All LAT Equipment

CE102 Spacecraft PRU – LAT DAQ

CE102 Spacecraft PRU – LAT SIU (IL), VCHP Heaters

CE102 Spacecraft PDU – LAT Anti-freeze and Make-up Heaters

Conducted Emissions Common Mode – All LAT Equipment

RS103 Perform – BEA and Tracker Tower

RS101 Perform – BEA and Tracker Tower

CS102 Spacecraft PRU – LAT DAQ

CS102 Spacecraft PRU – LAT SIU (IL), VCHP Heaters

CS102 Spacecraft PDU – LAT Anti-freeze and Make-up Heaters

Conducted Susceptibility Common Mode – All LAT Equipment

CS06 Operate – All LAT Equipment

CS06 Perform – All LAT Equipment

Back-up Slides

CE 102 LAT PDU – TPS (TEM, CAL, TRKR), EPU (IL), GASU (ACD BEA, IL), PDU (IL)

CS102 LAT PDU – TPS (TEM, CAL, TRKR), EPU (IL), GASU (ACD BEA, IL), PDU (IL)