glast lat projectoct 05 4.1.7 daq & fswv3 1 glast large area telescope: electronics, data...

GLAST LAT Project Oct 05

4.1.7 DAQ & FSW V3 1

GLAST Large Area Telescope:GLAST Large Area Telescope:

Electronics, Data Acquisition & Flight Software W.B.S 4.1.7

Analysis of cPCI Backplane Connector Assembly xray’s

Gunther [email protected](650) 926-4257

Gamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope


4.1.7 DAQ & FSW V3 2

Backplane AnalysisBackplane Analysis

• Method: give following information for each backplane– Starting point: list of pins supplied by GSFC identified as

possibly under-fill– Identify pins in that list which are not used

• Pins already identified on SLAC’s spread-sheet• Pins not on the spread-sheet

– There is no reason to spend time discussing the fill of any pins not used anyways

– Of the remaining pins, list of pins used• Pins already identified on SLAC’s spread-sheet• Pins not on the spread-sheet• Discuss fill of both


4.1.7 DAQ & FSW V3 3

Notes (1)Notes (1)

• Number of pins soldered on backplane excluding shield-pins (which are not used and thus ignored)– P1: 25 rows– P2: 22 rows– P3: 19 rows– P4: 25 rows– P5: 22 rows– Each row: columns Z, A, B, C, D, E, F

• Z and F are shield pins, not used– Total number of pins potentially used – 113 x 5 = 565 for each slot, times 4 slots = 2,260 pins– Identification of 4 slots

• X1: CPU (3u-card in P1, P2)• X2: CPS (3u-card in P4, P5)• X3: SIB (6u-card in P1-P5)• X4: LCB (6u card in P1-P5)

• Connectors not used for flight– X1: P3, P4, P5 – X2: P1, P2, P3– X3: P2, most of P3

• (P3 only uses: A19 (dclk); A1-E1 (gnd); A5-E5: (3.3V); B8-B14 (gnd); gnd and 3.3V redundant on other connectors)

– X4: P2, P3• Following connector are used for EGSE only, thus ignored for flight crates

– X1: P4/P5 holds custom Serial card, not used/integrated for flight– X2: P1/P2 holds commercial Ethernet card, not used/integrated for flight


4.1.7 DAQ & FSW V3 4

Notes (2)Notes (2)

• Comment to intentionally shorted shield pins (3 pins on row Z or row F) apparent on some xrays– Mostly, center pin identifies row in which pin was to be

touched-up– Wanted some kind of indication that correct pin was in fact

touched-up just in case that no change might be apparent before/after touch-up

– Shorts were removed after xray but before QA, although shorts would have no effect since • Shield pins already shorted to each other via

board/connector• LAT does not use shield pins anyways


4.1.7 DAQ & FSW V3 5

First Flight Backplane 2414First Flight Backplane 2414

• Total of ~ 2,000 pins looked at in xray• 22 pins identified on GSFC list• Not used (18 pins)

– Already identified on SLAC list • X1: P5-D11; P5-C12; P5-D12; • X2: P1-B17• X3: P1-B17

– Not used from remaining identified (X1-P5, X2-P1 not used as stated)• X1: P5-E11 • X2: P1-A19• X2: P2-C10, B11, C11, D11; P4-C6• X3: P1-B2 ; P1-B6 (red+5); P5-B2 (ch-gnd); P5-C14 (red+5), P4-B21 (redGND);• X4: P5-B5 (red+3.3)

• Used– Already identified on SLAC list

• X1: P1-B15 (Frame#); • X3: P1-A7 (AD30);

– Not on SLAC list • X1: P1-C23 (AD3) ; • X3: P1-D16 (stop_n)


4.1.7 DAQ & FSW V3 6

Second Flight Backplane 2415Second Flight Backplane 2415

• Total of ~ 2,000 pins looked at in xray• 18 pins identified on GSFC list• Not used

– Already identified on SLAC list (7 pins)• X2: P1-B3; P4-A15; P4-B23; • X3: P1-B8; P2-C12; J4-C1, J4-C16

– Not used from remaining identified• X1: P1-A19 (3.3V, one of 7 pins, not needed)• X3: P2-B12; P3-C1 (red+5), C3 (red+5), E4• X4: P1-B1


• X4: P1-C23(AD3); P4-C11(EI_PRIM_5_N); P4-C21(EI_PRIM_2_P)

– Not on SLAC list • X1: P1-B19 (AD15), P1-A20 (AD12) ;


4.1.7 DAQ & FSW V3 7

Third Flight Backplane 2420Third Flight Backplane 2420


– Already identified on SLAC list • None

– Not used from remaining identified• X1: P2-C21 • X2: P1-D25 • X3: P2-E8, B13• X4: P5-C22

• Used– none


4.1.7 DAQ & FSW V3 8

Fourth Flight Backplane 2418Fourth Flight Backplane 2418


– Already identified on SLAC list • None

– Not used from remaining identified– X1: P2-B5, P4-E7, D8, E8, D9 (P4 not used)– X2: P1-D11, B23, B24, C24; P2-B1, C1; (P1, P2 not used)– X2: P4-C9 (red+5); P5-A5 (red-28)– X4: P5-D21


• None

– Not on SLAC list • X1: P2-B6 (GBM RDNT)• X3: P1-E7 (AD27)


4.1.7 DAQ & FSW V3 9

Fifth Flight Backplane 2419Fifth Flight Backplane 2419


– Already identified on SLAC list • X1: J5-C13, B15

– Not used from remaining identified• X1: P5-C15, A18 (X1-P5 not used)• X3: P2-D10• X4: P2-A10

• Used– none


4.1.7 DAQ & FSW V3 10

First Flight Spare Backplane 2416First Flight Spare Backplane 2416


– Already identified on SLAC list (17)• X1: P2-C10 • X2: P1-D11, A17, D19, A21 (P1 not used as indicated) P1-D11, A17, D19, A21 (X2 not used as

indicated); P5-B6, C6 (redundant as indicated)• X3: P3-A4, B4, C5, D5, D6 (P3 not used as indicated)• X4: P3-E10

– Not used from remaining identified• X1: P2-B12, B13, C21• X2: D25 (gnd red)• X3: P2-A7, B7, A8, B8; P4- D24 (not used), C25(gndred), D25 (not used); • X4: P2-B18, C18; P4-D6 (not used),


• None

– Not on SLAC list• X2: P4-D2 (PRIM_SPO1_P), D3 (PRIM_SPO0_N), C25 (CLK_OUT_PRIM_P), P5-D2

(SPARE_TO_LCB_0), B21 (28V_RET), D21 (SPI_PRIM_RDNT_SEL)• X3: P1-A22 (AD7); P4-D20 (SC_RDNT_PWR_PDU_RDNT_SEL), P5-A19 (PRIM_1553_P)• X4: P4-C23 (EI_PRIM_1_P); P5-D1 (GND)


4.1.7 DAQ & FSW V3 11

SummarySummary

• 5 Flight boards (2414, 2415, 2420, 2418, 2419)– > 10,000 pins checked– 67 pins called out by GSFC as questionable– Of those 14 were already on SLAC spread-sheet identified

as not used– 53 pins remaining– Of those 42 are not used (no need to discuss fill)– Remaining are 11 pins to examine (of those 6 were on

SLAC list)– Next pages show all 11 pins

• 1st flight spare (2416)– 42 pins called out by GSFC as questionable– Of those 31 are not used (no need to discuss fill)– Remaining are 11 pins to examine– Next pages show all 11 pins


4.1.7 DAQ & FSW V3 12

FlightFlight


4.1.7 DAQ & FSW V3 13

X-ray of pins 2414: X1-P1-B15X-ray of pins 2414: X1-P1-B15

GLAT2414 X1 P1 B15

FRAME#

Void a bit bigger than on one of the previous cross-sections shown below.Would estimate that to be about 75% fill and the pin on the right to be at least 65%


4.1.7 DAQ & FSW V3 14

X-ray of pins 2414: X1-P1-C23X-ray of pins 2414: X1-P1-C23

GLAT2414 X1 P1 C23

AD3

Fill ~ 75%, based on simple ratio of 3 out of 4 shows solder fill.


4.1.7 DAQ & FSW V3 15

X-ray of pins 2414: X3-P1-A7X-ray of pins 2414: X3-P1-A7

GLAT2414 X3 P1 A7

AD30

Fill >80%, assuming 5 out 6 ratio filled.


4.1.7 DAQ & FSW V3 16

X-ray of pins 2414: X3-P1-D16X-ray of pins 2414: X3-P1-D16

GLAT2414 X3 P1 D16

STOP_N

Fill ~ 80%, based on simple ratio of 3.5 out of 4.5 shows solder fill.


4.1.7 DAQ & FSW V3 17


GLAT2415 X1 P1 A20

AD12

80% fill based on 4.5 out of 5.5 fill ratio.


4.1.7 DAQ & FSW V3 18


GLAT2415 X1 P1 B19

AD15

>90% fill.


4.1.7 DAQ & FSW V3 19


GLAT2415 X4 P1 C23

AD3

65% fill based on 2 out of 3 fill ratio.


4.1.7 DAQ & FSW V3 20


GLAT2415 X4 P4 C11

EI_PRIM_5_N

>70% fill assuming 2.25 out of 3 fill ratio. Summed voids to get to 0.75 voids.


4.1.7 DAQ & FSW V3 21


GLAT2415 X4 P4 C21

EI_PRIM_2_P

80 % fill assuming 2.4 out of3 solder fill.


4.1.7 DAQ & FSW V3 22


GLAT2418 X1 P2 B6

GBM RDNT

70 % fill assuming 4 out of5.5 solder fill.


4.1.7 DAQ & FSW V3 23

X-ray of pins 2418: X3-P1-E7X-ray of pins 2418: X3-P1-E7

GLAT2418 X3 P1 E7

AD27

65 % fill assuming >3 out of5 solder fill.


4.1.7 DAQ & FSW V3 24

Flight SpareFlight Spare


4.1.7 DAQ & FSW V3 25


GLAT2416 X2 P4 D2

PRIM_SPO1_P

80 % fill assuming 4 out of5 solder fill.


4.1.7 DAQ & FSW V3 26


GLAT2416 X2 P4 D3

PRIM_SPO0_N



4.1.7 DAQ & FSW V3 27


GLAT2416 X2 P4 C25

CLK_OUT_PRIM_P

90 % fill.


4.1.7 DAQ & FSW V3 28


GLAT2416 X2 P5 D2

SPARE_TO_LCB_0



4.1.7 DAQ & FSW V3 29


GLAT2416 X2 P5 B21

28V_RET



4.1.7 DAQ & FSW V3 30


GLAT2416 X2 P5 D21

SPI_PRIM_RDNT_SEL



4.1.7 DAQ & FSW V3 31


GLAT2416 X3 P1 A22

AD7

> 65 % fill assuming 4 out of6 solder fill.


4.1.7 DAQ & FSW V3 32


GLAT2416 X3 P4 D20

SC_RDNT_PWR_PDU_RDNT_SEL



4.1.7 DAQ & FSW V3 33


GLAT2416 X3 P5 A19

PRIM_1553_P

>65 % fill assuming 4 out of6 solder fill.


4.1.7 DAQ & FSW V3 34


GLAT2416 X4 P4 C23

EI_PRIM_1_P

>65 % fill assuming 3 out of5 solder fill.


4.1.7 DAQ & FSW V3 35


GLAT2416 X4 P5 D1

GND

70 % fill assuming 4 out of5.5 solder fill.


4.1.7 DAQ & FSW V3 36

Conclusion (1)Conclusion (1)

• All boards were conformal coated a while ago• The boards are at different stages in assembly• Touching up boards now will require stripping off some conformal coat (not difficult)• Flight

– 2414: 4 pins ok– 2515: 5 pins ok– 2420: no issues– 2418: 2 pins ok (might touch these up, but no great hope of improvement)– 2419: no issues

• Flight spare– 2416: 11 pins. Looks ok although we might try to touch up several of those pins.

• Touch-up showed good results when under-fill, but varying results when voids– Decided not to use pre-heat equipment on backplane since board is completely

covered with connectors not fabricated to be soldered. More risk than benefit in our view.

• In summary although fill is not ideal and what we would like, it is acceptable considering all other constraints– Qual testing of example boards (using short-open tests) did not show any issue even

with 40+ pins filled less than 50% fill, 100+ less than 60%, or 320 < 70%– TC/Vib/Thermal-vacuum did not show any issues on the proto-flight SIU crate (with

flight assembled SIB/CPS/LCB/CBP/RAD750) and those boards had more voids and underfill than the above flight backplanes)

• Definitely improvement from…see next page


4.1.7 DAQ & FSW V3 37

Conclusion (2)Conclusion (2)

• Xray of backplane assembled in same lot as other backplanes (#2411)

• Passed visual inspection by SA and SLAC (no underfill apparent from solder side)

• Would have been large risk to fly such a board

• Shows that recommendation by GSFC to xray boards was definitely good idea to say the least

• We were able to improve fill via touch-up, but board is only used as secondary spare

glast lat projectoct 05 4.1.7 daq & fswv3 1 glast large area telescope: electronics, data...

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