I am working on a large Oil and Gas Project.
On the Onshore scope, we have a requirement to provide redundancy architecture for the Local Historian Server. Primary Historian will be in Central Equipment Room (CER1) and Secondary will be in one of the Local Equipment Room (LER). This is to ensure that in case CER1 is not available at any time, the operations can be performed from the Field Operations Building (FOB).
To effectively perform the operations from FOB, this Secondary historian will be required.
For these, I have the following questions.
Can you please advise on the above questions?
Many thanks in advance and kind regards,
Sagar Gadre
I assume you are using the Embedded DeltaV Continuous historian on these systems.
You cannot setup redundancy in the manner you describe.
You must set up and license both historians to capture the data. If one fails, you will have to point your clients to the second historian.
Both historians will capture and store their historical data, but do not interact with each other to provide store-and-forwarding functionality to aggregate their data to fill in gaps.
I do advise submitting this requirement to the User Driven Enhancement Program:
www.userideas-emerson.com
In reply to Anonymous:
Yes Sagar, that is pretty much how it will happen. You can point your PHV application to any of the running historians and or Event Chronicles. PHV has a setting where you designate which historian would be the "Default" historian.
And as each workstation has a built in Continuous Historian with something like 250 points, if areas are assigned properly, you may be able to get away without having to designate a second server for historian functions. It sounds like your project is a bit bigger though, so a second server-historian (or scale up of the workstation historians) would be necessary.
The trick then becomes merging the data. If the CER1 historian is offline for some time, when it is brought back online it will be missing data. We need a function in DeltaV Historian Administrator that would merge or fill in the gaps of the missing data from all available historians. You could export the data from the online historian and attach it to the one with missing data...I think. I've never actually tried that. Youssef, you ever do anthing like that? Can you move an XFC file from one server to another?
-Travis
Sagar,
You are correct about the order of events. When the historian comes back up, connecting and polling for data during the outage will yeild 'NO DATA' or something like that. Your users will need to know how to change the historical server within PHV to access the missing data. It will not automatically do this.
In reply to Travis Neale:
From BOL - "The primary storage area may also contain zero or more extended historical data sets that have been placed back online through the use of the Continuous Historian Administration tools. These data sets may be for any history tags for any period of time (without continuity with the active and current historical data sets)."
It seems feasible that if you take historian A's data, export it, re-store it as an extended data set on historian B that the gaps could be filled. I've never tried it.