Backfilling of trends/alarms in 800xA or Compact HMI from Remote PLC
I would like to know if 800xA or Compact HMI has functionality for backfilling of trends/alarms from remote PLC. Remote PLC is connected with xA/Compact HMI via Ethernet as normal communication path and GSM modem as emergency communication path. If Ethernet is broken, communication has to switch to GSM, but if GSM is not working too, remote PLC has to collect trends/alarms in his memory and after restoring of GSM or Ethernet xA/Compact HMI has to read-out every collected data and backfill trends/alarms logs with time-stamp received with data from remote PLC. Is this possible with xA or Compact HMI? If no - is there ABB's product with such functionality? Is this possible for AC500 to be remote PLC, which libraries has to be used?
Basically, normal communication path will be Ethernet, so history logs will be collected by xA or CompactHMI in normal way. But if Ethernet connection will be broken, same history logs should be collected via Dialed History up to the moment when Ethernet going back in normal state. Is it possible to combine different behaviour for History Logs? Or connection should be always of type Dialed with virtual mapping of COMx-port to Ethernet if everything is OK and switching from this mapped COMx-port to usual COMy-port if Ethernet is broken and vice versa? Do you know if this possible at all?
Another way could be an HDA OPC server for AC500 if it is available. Did you heard about such HDA OPC server?
Theres no OPC-HDA server for the AC500 PLC. An HDA server is an interface to a historian, not a PLC.
You could certainly Log the data into both regular logs and Dialed Logs so you would always have the data available, but the 800xA Trend displays will not use this data seamlessly. You need to select one or the other to display the data and you cannot merge one trend into another to fill missing data in the 800xA system.
But if all you require is a backup that you could export to a third party historian in the case of an occasional network failure then this could possible work. Its not a good solution though.
You should probably stick with Dialed history if you expect the link to be unreliable.