LAT EMI Test LAT test levels derived from

LAT EMI Test • LAT test levels derived from LAT-SS-0778 • Use CAL EMI test procedure as template – LAT-PS-03929 -03 • Test Suite: – – – – – CE 102 Conducted Emissions, Power Leads, 10 k. Hz to 10 MHz, MIL-STD-462, CE 03 CECM Conducted Emissions, Time Domain, 150 MHz Bandwidth CS 102 Conducted Susceptibility, Power Leads, 10 k. Hz to 10 MHz, MIL-STD-462, CS 02 CSCM Conducted Susceptibility, Common Mode, 30 Hz to 150 MHz, MIL-STD-462, CS 02 CS 06 Conducted Susceptibility, Spike, Power Leads, MIL-STD-462 RE 101 Radiated Emissions, Magnetic Field, 20 Hz to 50 k. Hz RE 102 Radiated Emissions, Electric Field, 10 k. Hz to 18 GHz, MIL-STD-461 E RS 101 Radiated Susceptibility, Magnetic Field, 20 Hz to 50 k. Hz RS 103 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 • RS 103 upper limit of 18 GHz (40 GHz) • Limited area of RS 101 test – Requires scanning each 10 cm x 10 cm area, ~16 min/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 2 m cable lengths

Radiated Test Configuration

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, ~4 W/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 2 m from LAT I/F – CE 102, CS 102 (10 k. Hz - 150 k. Hz), CSCM (30 Hz - 150 k. Hz), 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 ~5 cm for LAT I/F – CS 102 (150 k. Hz - 150 MHz), CS 06, CSCM (150 k. Hz - 150 MHz) – 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

RE 102 - Integrated LAT

RE 101 – All LAT Equipment

CE 102 Spacecraft PRU – LAT DAQ

CE 102 Spacecraft PRU – LAT SIU (IL), VCHP Heaters

CE 102 Spacecraft PDU – LAT Anti-freeze and Make-up Heaters

Conducted Emissions Common Mode – All LAT Equipment

RS 103 Perform – BEA and Tracker Tower

RS 101 Perform – BEA and Tracker Tower

CS 102 Spacecraft PRU – LAT DAQ

CS 102 Spacecraft PRU – LAT SIU (IL), VCHP Heaters

CS 102 Spacecraft PDU – LAT Anti-freeze and Make-up Heaters

Conducted Susceptibility Common Mode – All LAT Equipment

CS 06 Operate – All LAT Equipment

CS 06 Perform – All LAT Equipment

Back-up Slides

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

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