Sirius 800 Series User Manual
Sirius 840/850: Video Crosspoint Arrangement
Crosspoint Modules 10.3
Iss 5 Rev 7
Page 163
© 2017 SAM
10.3.1 Sirius 840/850: Redundant Crosspoint Operation
The redundant crosspoint design is based around protecting against a single signal path
failure. In normal operation, all the routes pass through the four main routing crosspoint
modules.
The redundant signal path algorithm checks the signal paths on each of the main crosspoint
modules in turn by configuring the redundant crosspoint module to mimic the main module
being checked. The algorithm compares the signal standard of each signal path through the
main crosspoint module with the signal standard of the equivalent path through the redundant
module.
The algorithm also compares the signal lock status of each signal as it enters and leaves the
main crosspoint module. A difference between the incoming and outgoing signal lock status
indicates a route failure.
Each signal path is compared in turn until all of the paths on the main module have been
checked. The algorithm then moves on to check the next main crosspoint module in the same
way.
If the algorithm finds a difference in the signal standard of a path passed by the main and
redundant crosspoint modules or if a signal lock status check fails for a route the failure is
flagged and the control system can (if configured) move the route to the redundant crosspoint
module. Once this has happened, the redundant crosspoint cannot take the place of any of
the other three main crosspoint modules. If more routes fail on the main crosspoint that has
already been substituted by the redundant crosspoint, then they can move to the redundant
crosspoint.
The algorithm will continue to check the crosspoint module with the failure for further failures.
The other three main crosspoint modules are no longer checked. At this point the crosspoint
matrix is still capable of setting all 576
2
routes but redundancy has been lost. This failure must
be addressed immediately to regain redundancy for the crosspoint matrix.
Additionally if any one of the following situations occur the router controller will move all
routes to the redundant crosspoint module:
•
A main crosspoint module is removed from the router.
•
The router controller looses communications with a main crosspoint module.
•
A main crosspoint module reports one or more of its power rails has a fault.
To replace a failed crosspoint module all the routes on the failed module must be moved to
the redundant crosspoint module, see section 10.4.1 for details.
Checking of all of the main crosspoint modules will be resumed when the failed crosspoint
module has been replaced.
Example
:
Router pre-configured to move the failed route to the redundant crosspoint module.
•
Output 1 on Main Crosspoint 1 fails:
Output 1 on the output module switches to the redundant path
•
Output 7 on Main Crosspoint 1 fails:
Output 7 on the output module switches to the redundant path
Note:
Any failure needs addressing immediately to retain protection, see section 10.4.1 for
details.
