Operation Manual Part 1
Digital Liquid Cooled UHF
TV Equipment
Detailed operational description
9946 V1
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preliminary
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Numéro / Number Doc. Rev. Lan
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Information contained is this document is confidential, is THOMSON property and cannot be disclosed in whatever form without prior written authorization of THOMSON.
2.3.5. Processing of faults
2.3.5.1. Outline
Faults are detected by sensors (liquid flow/air pressure, temperature and reflectometer probes) and
surveillance devices inside the units (power supplies, SWR protection, ...).
Fault signals from these sensors are picked up:
♦ either by a loop protection system in the multiplex card,
♦ or by the fault processing system in the Central Processing Unit.
All faults without exception are also picked up by the following systems in the CPU:
♦ log book control system,
♦ display control system.
2.3.5.2. Fault analysis system
All fault signals received by the Central Processing Unit are analysed before being processed. This
analysis consists in checking that some other event is not responsible for the fault signal; some events
(transient phase anomalies, fault in multiplex card, amplifiers missing, ...) can cause anomalies on
other units.
Example:
When a multiplex card fault appears, the status data, which should pass through the
card, will not be picked up by the system. When this happens some faults will not be
processed.
Notes:
Although to a certain extent the various units are protected by the system the following
units have their own automatic protection systems:
♦ amplifier power supply,
♦ amplifiers,
♦ exciter system.
2.3.5.3. Fault processing facilities
The fault processing system generates commands, which protect the transmitter operation from the
fault signals, which occur. It reacts to the following events:
♦ air pressure/input liquid temperature fault,
♦ SWR/amplifier overdrive fault,
♦ SWR antenna fault,
♦ Automatic exciter changeover (only applies to the dual drive version),
♦ Automatic transmitter on-air/off-air switch,
♦ Re-setting of synthesiser.