CANOGA PERKINS 3240S SNMP Managed Fiber Optic Multiplexer - Manual (Page 47)

3240S F I B E R O P T I C M U L T I P L E X E R
3240S Fiber Optic Multiplexer
4.4 3240S NMS Operation
4.4.1 System Functions: Redundant Optics
The normal, or default, system mode of operation is:
• NOR mode (no system test)
• AUTO mode (as opposed to Manual PRI or SEC)
• Active Link is Primary
• Fault Relay is off, Alarm Indicator is not illuminated
• Local and Remote Composite Sync is good
• Backup Fiber Optic Link Monitor is good
Any change to this system state should result in an alarm, except Manual PRI or SEC. The following descriptions, one
through three, outline typical failure scenarios.
1) An Automatic Switch over from the Primary to Secondary Link. This results in the Fault Relay illuminating the Alarm
Indicator(latched), the Secondary Fiber Optic Link Indicator illuminates, and the Backup Fiber Optic Link Monitor
illuminates, indicating a condition other than normal operation. The remote unit will also switch to the secondary link.
This condition will remain until one of the following events happens:
• The Primary Fiber Optic Link recovers; which will cause the Backup Fiber Optic Link Monitor to resume operation
in the normal condition. No other changes should occur.
• The Secondary Optic Link fails; which will result in a crossover back to the Primary Optic Link. If the Primary
Link resumes functionality in a normal state, operation will resume on it; whereas if the fault is still present, the
system will oscillate back and forth between the Primary and Secondary Links every two seconds until a good link
is established. This condition will cause oscillations of the Active Link indicator.
2) A failure of the Backup Fiber Optic Link Monitor. This could occur at either end and will cause an alarm. In addition, the
Fault Relay is set at both ends. When the Backuplink Monitor indicates Good, the relay is reset at both ends.
3) A Power Supply Fails. This could occur at either end and will cause an alarm. No other symptoms show.
4.4.2 Commanding Test and Manual Operating Modes
System level or individual I/O ports can be set to loopback (local or remote) via the NMS or a manual switch setting.
Commanding a test mode will interrupt system operation and should be executed with caution. Appropriate warnings are
issued prior to execution of these commands when executed via the NMS. Commanding the manual modes will cause a
momentary interruption of service (assuming the alternate link is functioning properly). Warnings similar to those for the test
modes are issued when executed via the NMS.
All switches that can be controlled by the NMS must be in the NORM or AUTO position to do so.
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