Specifications

Gaia
GAIA.ASU.SP.ESM.00007
Issue 2.00
Page 25 of 79
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GAIA.ASU.SP.ESM.00007 (Avionics SCOE Req Iss 2).doc
3.6.2.2 PCDU Remote Terminal 1553 BUS Interface
This section only applies to Avionics SCOE Set #1 for Power Simulation requirements.
One special case of MIL-STD-1553B Remote Terminal simulation is that of the PCDU.
When simulation of the PCDU is required, some LCL circuits are simulated in hardware by the Avionics
SCOE (see Section 3.6.1 - Spacecraft Power Simulation).
Note: The need for LCL simulation in hardware is determined by the current Spacecraft configuration (which
Spacecraft Units are HWIL).
AVI-2565/CREATED/T
For those LCL circuits designated for hardware simulation, their state (ON/ OFF) shall be controlled
by the corresponding ON/OFF commands received by the PCDU RT.
AVI-2567/CREATED/T
In all test modes, the local Application Software shall decode the 1553 BUS commands and switch
ON/OFF, as directed, the corresponding LCL circuit.
AVI-2568/CREATED/T
In closed-loop test mode, the RTS shall directly control the state of the LCL circuits in response to the
PCDU 1553 BUS commands.
AVI-2569/CREATED/T
For those LCL designated for hardware simulation, their status (ON/OFF) and output currents shall be
read from the corresponding LCL circuits.
AVI-2570/CREATED/T
In open-loop test modes, the local Application Software shall read the STATE and currents for those
LCL circuits simulated in hardware and send that data on the 1553 BUS as requested.
AVI-2571/CREATED/T
In closed-loop test mode, STATE and currents of the simulated LCL circuits shall be available to the
RTS for insertion in the 1553 BUS response.