Data from one Historian can be replicated to one or more other Wonderware Historians, creating a “Tiered” relationship between the historians. Figure 1 (below) shows a common configuration in which data from multiple Historians (called Tier-1 Historians) is fed into a single centralized historian (called a Tier-2 historian).
Figure 1: The Tier-2 Historian Stores Data Replicated from the Tier-1 Historians
A Tiered Historian provides three types of replications:
- Analog Summary, and
- State Summary Replications
- Simple replication retains the original data resolution while Summary replications provide periodic summaries of high resolution data.
- Simple replication replicates all values in the Tier- 1 Historian to the Tier-2 Historian. Analog, discrete, and string tags can be configured for simple replication.
- Analog Summary replication produces summary statistics for analog tags. The statistics relate only to the recorded interval.
- State Summary replication summarizes the various states of a tag value. State summary replication can be applied to analog (integer only), discrete, and string tags.
This Tech Note shows you how to configure a Tier-1 Historian to replicate Analog Summary and State Summary data onto a Tier-2 Historian replication server. Analog and State summary data can be then stored for retrieval by configuring replication tags that correlate with the source tag.
- The Tier-2 Historian should be at the same version, or should be a newer release than the Tier-1 Historian(s). It should have enough licensed tags for data being replicated.
- Be careful not to create or modify a replicated tag on a Tier-1 Historian to have the same tagname that already exists on a Tier-2 Historian. The system does not prevent you from having a replicated tag on a Tier-2 Historian receiving data from two or more different Tier-1 Historians. However, when you retrieve data for that replicated tag on the Tier-2 Historian using the tagname, an incorrect blend of data from the two (or more) data sources is returned.
- You can use summary replication instead of event-based summaries. Compared to event-based summaries, replicated summaries:
• Support more types of calculations.
• Are stored to History Blocks, instead of in SQL Server tables, thus taking advantage of all that the Historian storage subsystem has to offer in terms of data compression and throughput as compared to regular SQL Server database storage.
• Can be retrieved using the full array of real-time query extensions provided by the Historian.
- Wonderwae Historian Server 10 SP1 P01 or later
- Microsoft SQL Server 2005 SP3 (32-bit)
- Microsoft SQL Server 2008 R2 (32-bit)
This Tech Note assumes that you are familiar with Wonderware Historian Server and Microsoft SQL Server Management Studio. If you have any questions regarding the Microsoft SQL Server, contact Microsoft Technical support at www.microsoft.com for further assistance.
- From a Tier-1 Historian, open the ArchestrA System Management Console (SMC)
- Expand Historian\Historian Group\<Computer name>\Configuration Editor\System Configuration\Replication, right click on Replication Servers then select New Replication Server…
- The New Replication Server dialog box appears (Figure 2 below).
- Enter the node name or IP Address of the Tier-2 Historian.
- The Store & Forward path will be automatically filled out. You can modify the path if necessary.
- Click the Test Connection button.
Figure 2: Test Replication Server Connection
The test should be successful with a pop-up message (Figure 3 below).
Figure 3: Connection Test Successful
- Click OK.
- Click Next. We can accept default settings like the figure below.
Figure 4: New Replication Server – Advanced (Default Settings)
- Click Finish. The Tier-2 replication server item appears in the SMC (Figure 5 below).
Figure 5: Tier2 Historian Item in SMC
- Expand the Tier-2 Historian item. In this example, it is called HistorianTier2.
- Expand the Analog Summary Replication folder.
- Right-click on the 15 Minutes schedule and select Add Multiple Tags.
For this example, the following tags are added to the schedule. SysTimeMin is a Historian built-in tag, others were imported from the Wonderware InTouch Demo application: SysTimeMin, ReactLevel, ReactTemp, and ProdLevel.
Figure 6: Add Multiple Tags for Replication
- Click OK. The Add Multiple Tags – Step 2 of 2 – Create replicated tags window appears.
Figure 7: Create Replicated Tags
- Click Apply then Close. The tags appear in the 15 Minutes item (Figure 8 below).
Figure 8: Source and Destination Tag Names
- Now, expand the State Summary Replication item, then right-click on 30 Minutes and select Add Multiple Tags.
- In this example, the following tags (imported from the Wonderware InTouch Demo application) to the 30 Minutes schedule: WaterValve, ConcValve, ConcPump, TransferPump.
Figure 9: State Summary Replication/30 Minutes Tags
- On the left pane of the SMC, right-click the Configuration Editor and click Commit Pending Changes to apply the changes to the Runtime database.
- Click Commit, then OK.
Figure 10: Commit Changes
Figure 11: Changes Committed
- From the Tier-1 Historian (HistorianTier1 in this example), on the left pane of the SMC, expand the Management Console item and click Replication.
The name of the Tier2 Historian (HistorianTier2 in this example), status, total tags, etc. appears in the right panel as (Figure 12 below).
Figure 12: Replication Operation
The panel includes the following columns:
- Replication Server: The name of the remote replication server, or “Local Replication” when replicating locally.
- Status: The status of replication to the replication server.
- Total Tags: The total number of tags being replicated to the replication server.
- Values/Sec: The average number of data values replicated per second.
- Sync Queue Values/Sec: The average number of synchronization queue values replicated per second.
- Total Values: The total number of values being replicated.
- On the Tier-2 Historian (HistorianTier2 in this example), on the left pane of the SMC, expand the Configuration Editor – Public Groups, and click All Analog Summary Tags. The name of replicated tags from Tier-1 Historian (HistorianTier1 in this example) should appear right panel under the Referenced Tag Name column.
Figure 13: All Referenced Tag Names/Analog Summary Tags
- Similarly, expanding the All State Summary Tags item displays in the right panel under the Referenced Tag Name column.
Figure 14: All Referenced Tag Names/State Summary Tags