COBHAM Sailor 900 VSAT, Technical Manual

Page: 164 / 356

Removal and replacement of ADU modules
8-22 Chapter 8: Service & maintenance 98-133966-G1
The ISM shall — based on request from the PCM — provide
information about movement of the parabolic reflector, in the form
of samples from gyro- and acceleration-sensors.
The ISM board is:
• Communication as slave of the ADU Bus connecting the Inertial
Sensor Module (ISM), the DC-motor Driver Modules (DDM), the
Polarization Motor Module (PMM), and the Pedestal Control
Module (PCM).
• Collection of contemporary sample-data sets from all sensors
and provide those to the PCM on request. A set of samples
should be collected within less than 100 micro seconds.
• High stability and accuracy 3 axis accelerometer and angular rate
sensor.
• Prepared for wide range 3 axis accelerometer.
• Calibration of sensor offset, gain, and misalignment over
temperature (stored in non-volatile memory).
• Secure fixing to the parabolic reflector.
• Diagnosis of board supplies, sensor inputs, etc.
17.Elevation locking pin to lock the antenna dish in a fixed position (for
safety during service) (not visible on photo).
Figure 8-20: ISM – Block diagram
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SAILOR900TM.book Page 22 Monday, September 16, 2013 11:01 AM