Data Locations (DLs) are user friendly names for entities from which the Sapphire Collector can read data. The Sapphire Collector supports various types of Data Locations, such as:
DA OPC Servers - allowing data to be collected and historized for any DA compliant OPC Servers.
Plugin Dlls - allowing non OPC data such as SNMP, Windows Performance counters, Network pings, OPC UA or Script execution results to be historized in the Sapphire Collector.
In build performance counters that can be used to monitor the performance of the Collector itself (the __PERF__ and __SYSTEM__ DLs).
Data Locations are a fundamental concept in SapphireTrend, since the DL forms part of the unique name used to address individual data items with the Sapphire Collector. By prefixing the item name with the DL, it allows items with the same name to be read from multiple Data Locations.
Note: It should be noted that once items have been assigned to a DL, they cannot be re-assigned to another DL.
It is therefore a good idea to use general names for Data Locations such as "Cooling Tower 1" rather than using the name of the specific OPCServer where data is being read from. By doing this the infrastructure used to get data can be changed (for example swapping in a different OPC Server or relocating an OPC Server to a new node) without invalidating the meaning of the DL name.
For Data Locations that reference OPC Servers a further level of indirection is provided via Data Sources. A Data Source refers to a specific instance of an OPC Server and a Data Location can consist of one or more Data Sources.
Where multiple Data Sources (i.e. OPC Servers) are defined for a DL, the Collector can provide Failover capability automatically switching to another OPC Server if the one in active use fails to return data. As such, one of the Data Sources is designated as the 'Primary' and will be the one the Collector tries to use by default.
If Client side DCOM registration has been performed for an OPC Server on the Sapphire Collector host node, then a Data Location can be added for the Server via the 'Discover' button on the DLs tab of the stManager.
Note: When using this method be sure to change the name of the Data Location to something other than the default to avoid future problems if the data path to the OPC Server changes (as described above).
When Client side DCOM registration has not been performed, a Data Location can be added manually by Browsing the local network for the required OPC Server(s).
Note: From release V3-3 onwards, it has been possible to define additional Failover OPC Servers that should be used when collecting data for a given Data Location. This provides a degree of redundancy to the data collection process.