Historian Overview
- Historian Server
- The Historian server is the central point for managing all of the client and collector interfaces, storing and (optionally) compressing data and retrieving data. All tag data (numbers, strings, blobs) are stored in a proprietary format in Data Archives. Each Data Archive represents a specific time period of historical data. You can further segregate your tags and archives into Data Stores.
A Data Store is a logical collection of tags used to store, organize, and manage tags according to the data source and storage requirements. A Data Store can have multiple data archives, and includes logical and physical storage definitions.
The primary use of data stores is segregating tags by data collection intervals. For example, you can put name plate or static tags where the value rarely changes in one data store, and put process tags in another data store. This can improve query performance.
Historian data archives are data files with the extension *.iha, each of which contains data gathered during a specific period of time. Archives are generally time-based, such as daily archives.
The Historian Data Archiver is a service that indexes all information by Tagname and Timestamp and stores the result in an *.iha file. The Tagname is a unique identifier for a specific measurement attribute. For iFIX users, a Historian Tagname normally represents a Node.Tag.Field (NTF). Searching by Tagname and Time Range is a common and convenient way to retrieve data from Historian. If you use this technique to retrieve data from the Archiver, you do not need to know which archive file on the Historian server contains the data. You can also retrieve data using a filter tag.
Historian is capable of storing many different data types, such as Float, Integer, Strings, Byte, Boolean, Scaled, and BLOB (binary large object data type). The source of the data defines the ability of Historian to collect specific data types. If licensed for the Alarm and Event option, then the server also manages the storage and retrieval of OPC alarms and events in a SQL Server Express.
- Collectors
- The Historian includes several types of data collectors for collecting data from a wide variety of applications including: iFIX, OPC, OPC HDA, OPC UA Data Access (Windows), OPCUA (Linux), OPC Alarms & Events, Text Files (.csv or .xml), and OSI PI.Note: To collect data from CIMPLICITY, you must use the Historian OPC collector with the CIMPLICITY OPC Server.
The Calculation collector is designed to perform math and analysis on Historian data and store the results in tags, on the server. The Server-to-Server collector has the same calculation capabilities as the Calculation collector, but it stores the results in tags, on a remote server.
Most collectors are capable of performing first-order deadband compression as well as a browse and add configuration, and store and forward buffering.
Note: Standard Collectors that are included as part of the product will not consume a CAL (Client Access License). Other interfaces developed by customers or system integrators using the Collector Toolkit or APIs will consume a CAL for each instance or connection.Historian Data Collector Cloud (Bi Modal) Connectivity:
In principle, all Historian Data Collectors read data values from a specified source and write them to a Historian Server. Some of the Historian Data Collectors are Bi-Modal collectors. This means most of the Collectors have the capability to write Time Series data either to GE Historian Server or to a Predix Time Series Service on Cloud. This can be done by changing the Collectors destination configuration either as Historian or Time Series at the time of collector installation.
- Clients
- All client applications retrieve archived data through the Historian API. The Historian API is a client/server programming interface that maintains connectivity to the Historian Server and provides functions for data storage and retrieval in a distributed network environment.