LAT Electronics, Data
Acquisition & Instrument Flight SoftwareACD-Test-Stand #2
Noteworthy for this test-stand
can handle 4 FREE card connections on the primary GASU and 4 on the redundant GASU for a total of 2 complete BEA assemblies
supply voltage and frequency to FREE can be varied with this version of GASU to explore FREE margins
only tested at room-temperature
one GASU-ACD cable is included in this shipment (you can use the extra cables from the last shipment)
CAUTION
the CALSTROBE delay and/or the TACK delay in the trigger sequencing register must not be set to 02 (hex). If set to 02(hex) the AEM will continually assert the NSCMND lines to all 12 FREE boards.
can not be subjected to thermal-vacuum tests, temperature cycling, vibration tests
THERE IS a TYPO in the JL153 connector pin assignment in the LAT-TD-03827-02 document (only applies when the FREE 3.3V is to be margin tested). Look for release 3 for correction, expected to be released 5-28-04. Error is that the voltage adjust pins called out adjust the GASU DAQ voltage, not the FREE voltage. No damage can be done but the FREE voltage won't change. The pin assignment is correct in LAT-TD-03664, so use that one.
28V or 3.3V supplied to the FREE can not be shorted to ground (< 3 ohms)
In addition the current drawn for the 28V FREE must be below 20 mA for durations exceeding 5 sec. The current from the 3.3V must be less than twice the ICD value for durations exceeding 5 sec. The GASU might have to be sent back to SLAC if these limits are exceeded. The DAQ/ACD need to finalize the maximum currents so the circuit can be finalized for flight, and that will be incorporated in one of the next GASUs.
Here are copies of the documents for reference. Retrieve directly from LAT-DOCs for released versions.
LAT-TD-03664 GASU-Based Teststands: Describes GASU-based test-stands; has pictures of GASU panel connectors, JL153 pin assignments, etc.
LAT-TD-03827-02 Test for EGSE ACD G3 Test Stand with GASU Instrumented to Simultaneous Test up to 4 FREE Cards (including Safe-to-Mate) Revision 02: Test procedure to test this G3 test-stand, includes set-up diagram/instructions for test-stand, use in conjunction with LAT-TD-03664
Certificate of Compliance from LAT QA (to be scanned in)
LAT-TD-3919 Limitations and Deviations from released drawings (as-built) (see note on top of this page)
NCR's (none to date)
Supporting Documents:
As-built Power-Switch Section on GASU DAQ Board of Test-Stand #2
LAT-TD-00639 ACD Electronics Module
LAT-TD-01545 Global Trigger Electronics Module
LAT-TD-01547 Command/Response Unit
LAT-TD-01546 Event-Builder Module