On a system we have a connector for a CPI HPA, and we have several connectors for different Mitec controllers.
The problem is that the backup HPAs can be reached only through the redundancy controller.
Sending the command to the HPA through the redundancy controller however uses a different command structure.
I'm now wondering what is the best solution from a technical perspective.
Some options are following, but maybe there are more?
- Creating a new connector for the HPA through controller communication
- Implement bus locking on the redundancy controller connectors and on the new HPA connector so that the two elements can share the same serial bus.
- Create a new connector for the HPA which sends commands to the redundancy controller element and in turn receives the responses from it.
- Adjust the redundancy controller connectors to be able to receive commands from another element
The redundancy controller is then the single master of the commands being sent on the serial bus to the controller.
- Adjust the controller connectors to have an additional smart serial connection
- The existing HPA code can remain the same but the element sends to the smart serial connection and the controller element changes the command structure to match what is needed to send through the controller.
To summarize the items:
-There is currently 1 main HPA connector that is directly communicating.
-There is currently 1 redundancy controller this is already being polled.
-The backup HPA device needs to be polled through the same RS-422 communication bus that the redundancy controller is already using. The same parameters are needed like the main HPA connector is having and the commands/responses are similar (1 extra byte is added).
In my opinion the best solution would be to adapt the main HPA connector and include a config parameter to indicate if this is a main or backup HPA to be polled. Based on that setting, there will be different commands used. As the RS-422 communication bus is being shared with the redundancy controller: add a lock/unlock action to the HPA connector and the redundancy controller connector. (lock/unlock actions will not be needed in case the HPA is configured as main). The backup HPA will need to be present on the same DMA like the redundancy controller element to let the locking take effect (also note that "serial single" cannot be used).
Alternative to avoid the locking could be to let the redundancy controller do all the polling and then let it fill in the data in either a DVE, or let it push its data to a remote HPA element that fills in the parameters. But that doesn't seem to be good alternatives as there already exists a connector that is being used for main HPA and already has the needed parameters and processing logic and has default built in support for StreamViewer, timeout,....