Training, Installation & Service Manual - Livewire Connections Ltd

Removal and replacement of ADU modules
16. Pedestal Control Module (PCM).
The PCM will - based on several inputs - control the position of
the parabolic reflector and the polarization angle of the
polarisation mechanism assembly via 3 brush less DC-motors
and a stepper motor.
The PCM board is:
• Modem communication with a below deck Antenna Control
Unit via a VSAT interface module (VIM).
• Control of the VIM module devices via a parallel interface
connector.
• Communication master of the ADU Bus connecting to the DCmotor
Driver Modules (DDM), the Polarization Motor Module
(PMM), and the Inertial Sensor Module (ISM).
• Communication with the GPS module.
• Provide power to the modules connected via the ADU bus
(motor drivers supplies and bus interface circuits' supplies)
with over-current protection (hot swap) via the bus cable.
• Modules are by means of shielded DB9 cables connected in a
chain in the following order: PCM — DDM (azimuth) — DDM (Xelevation)
— DDM (elevation) — ISM — PMM. PMM module
contains signal terminations.
17. Service switch.
In switch-off position the DC Motor Driver modules (DDM), the
Polarisation Motor Module (PMM) and the BUC are turned off for
safe conditions during service and repair. The switch must be in
on position for normal ADU operation. The switch only controls
movements and prevents any transmission. In Off position the
DDMs, PMM and BUC are turned off for safety during service and
repair of the ADU.
Figure 9-10: Service switch
9-16 Chapter 9: Service & maintenance 98-133966-E2