User's Manual

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Aprisa SR User Manual
Operation
In normal operation, the active radio carries all RS-232 serial and Ethernet traffic over the radio link and
the standby radio is unused with its transmitter turned off. Both radios are continually monitored for
correct operation and alarms are raised if an event occurs.
Both the active and standby radios send regular ‘keep alive’ messages to each other to indicate if they are
operating correctly. In the event of a failure on the active radio, the RF link and user interface traffic is
automatically switched to the standby radio.
The failed radio can then be replaced in the field without interrupting user traffic (see ‘Replacing a
Protected Station Faulty Radio’ on page 36).
Configuration Management
The Primary and Secondary radios are managed with the embedded web-based management tool,
SuperVisor (see ‘Managing the Radio’ on page 63) by using either the Primary or Secondary IP address.
Configuration changes in one of the radios will automatically be reflected in the partner radio.
To ensure all remote stations are registered to the correct (active) base station, changes to the Network
Table are automatically synchronized from the active radio to the standby radio. The Network Table is
only visible on the active radio. This synchronization does not occur if the Hardware Manual Lock is active.
Switch Over
The switch over to the standby radio can be initiated automatically, on fault detection, or manually via
the Hardware Manual Lock switch on the Protection Switch or the Software Manual Lock from SuperVisor.
Additionally, it is possible to switch over the radios remotely without visiting the station site, via the
remote control connector on the front of the Protection Switch.
On detection of an alarm fault the switch over time is less than 0.5 seconds. Some alarms may take up to
5 seconds to be detected.
The Protection Switch has a switch guard mechanism to prevent protection switch oscillation. If a switch-
over has occurred, subsequent switch-over triggers will be blocked if the guard time has not elapsed.
The guard time starts at 20 seconds and doubles each switch-over to a maximum of 320 seconds and
halves after a period of two times the last guard time with no protection switch-overs.