User's Manual

MODEL 2130 MARKER BEACON
2-10 Rev. A April, 2005
This document contains proprietary information and such information may not be disclosed to others for any
purposes without written permission from SELEX Sistemi Integrati Inc.
U33 and U16 comprise a 32 to 1 channel analog multiplexor controlled by latch U54 and inverter U17:D. All power supplies
with potentials greater than ±12V are scaled down by resistor networks RN12 and RN13 before presentation to U33.
Voltage reference U30 serves both as a reference check for the U31 A-D converter as well as the base reference for D-A
converter U56.
Buffer amplifier U29 presents the selected analog channel to A-D converter U31. Converter operation is controlled by the
latch U54 A_D_R/*C signal, with a TTL low initiating a conversion. Conversion status and data bus output of the
converter are read through buffers U46 and U47. Resistor networks RN11 and RN10 pull up the converter data bus during
tri-state conversion periods. Buffer inputs U46-3 and U46-4 are reserved to denote any major hardware revisions to the
RMS CCA that might occur in the future.
Operational amplifiers U35:C and U35:D and associated components form a full-wave rectifier/amplifier circuit for the
system AC current sensed on the BCPS CCA and routed on-board from J1-9. Potentiometer R93 will scale the output of
this circuitry to fit the ratios shown near TP23 and R93.
Operational amplifier U35:B buffers the System1 AC voltage sensed on the BCPS CCA and routed on-board from J1-29
after it is scaled by potentiometer R99 and transient protected by CR22. The scaled voltage can be measured at TP24 and
will behave according to the formula shown near this test point and resistor R98.
Operational amplifier U35:A and associated circuitry perform the same function for System2 AC voltage from J1-28 as
U35:B discussed previously.
Instrumentation amplifier U48 amplifies the differential signals Batt1_Curr+ and Curr- sensed on the BCPS CCA and
routed on-board from J1-7 and J1-8. These signals are transient protected by CR45 and CR46. Resistor R108 sets the gain
of the amplifier to that of the ratio shown near U48-6 and the scaled output can be measured at TP19.
Instrumentation amplifiers U49, U50, and U51 and associated circuitry perform the same function for Batt2_Curr+,
Raw1_Curr+, and Raw2_Curr+ from J1-6, J1-5, and J1-4 as U48 discussed previously. Raw1_Curr+ and Raw2_Curr+
represent the DC current sensed for the System1 and System2 power supplies. Batt1_Curr+ and Batt2_Curr+ represent the
charging or discharging currents of the System1 or System2 batteries.
D-A converter U56 creates test waveforms which are sent to both Marker Beacon1 (J3-18, J3-19) and Marker Beacon2 (J4-
18, J4-19) for test purposes. The test waveform from the U56 D-A converter is low-pass filtered by op-amps U6:A and
U6:B. Op-amps U6:C and U6:D, along with resistor network RN14, transform the ground-referenced test waveform to
differential levels before exiting to the Marker Beacons. The ground-referenced test waveform is also fed back to the A-D
converter (U16-10) and can be measured at TP29.
Address decoding is accomplished by decoders U23, U21, and U18. The devices decoded include the U4 SDRAM, the U1
and U2 flash ROMs, the U3 NVRAM, the U25 and U20 UARTS, the U45 and U42 parallel port data (read), the U32 parallel
port data (write), the U38 parallel port control, the U54 and U53 A-D/multiplexor control, the U43 and U44 configuration
switches/digital inputs, and the U46 and U47 A-D converter data bus.
The U8 microcontroller does not have an A0 address line so all external accesses are accomplished in a 16-bit wide (word)
format. The address map for the RMS CCA can be found near decoder U23.