Introduction to Historian module
The Historian module enables the storage of tag values and their corresponding timestamps in SQL databases or third-party time-series databases. This module is designed to streamline the collection and storage of data in its time context.
The Historian module provides an out-of-the-box solution for archiving historical data without programming requirements. Although it is possible to include custom data logging procedures in your solution using Scripts (.NET programming) and Datasets (SQL storage), the standard configuration tools of the Historian module can fulfill most typical data logging needs.
On this page:
Purpose and Key Concepts
Configuration of the Historian module is accomplished through the following sections: Target Database, Historian Table, and Historian Tag.
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TargetDB
The TargetBD defines the database where variables will be archived or read to be used in charts and calculations. The Target Database can be any SQL Database or, using the TagProvider Extensibility, it can also use third-party products designed to store long-term time-related values, known as time-series databases or Historian tools.
HistorianTable
The HistorianTable is a logical organization that groups Tags for historical archiving. Each Historian Table has a definition of which Target Database the group of Tags will be archived. You can also configure other standard settings that apply to all tags in that group in the Historian Table, such as when to save new data or how long to keep the data.
HistorianTag
The HistorianTag refers to any value contained in a Historian Table to be archived, whether an internal Tag or an external data reference. These variables are typically Tags defined in this platform, but you can also include dynamic references to external data using the TagProvider functionality.
Understanding the Historian module
Archiving Process Overview
The Historian module has a three-step archiving process:
An event triggers the request to archive a group of values. There are two types of events (Trigger or TagChange), which are configured in a Historian Table.
The Historian archives the values in the Target database. The Target Database can be a SQL Database or a TagProvider that is configured to act as a historian.
If Store and Forward is enabled, the data synchronization is executed. This option stores data in a local database if the Target Database is not available, and sends it to the target when it becomes available.
The archiving process considers two types of archiving events:
Trigger: The Trigger can be a Tag Value, Tag Property, or any object from the runtime namespace (e.g., server.minute). When a value change is detected in the object, the archive request event is generated. Only Tags of domain Server or objects residing in server-side namespaces can be used as Triggers since the Historian process runs on the Server computer. The Trigger is configured in the HistorianTable. All tags and objects connected to that HistorianTable will be requested to be archived, regardless of having or not a new value.
Tag Change: The Tag Change is a check-box on the TableHistorian configuration. Enabling this checkbox allows the Historian process to verify all tags connected to that HistorianTable. When the tag has a new value, the archive request event is generated. The request to archive will be generated only for the Tag that has a new value. However, according to the Historian Target Database, only the tag or all tags in the group will be archived. Further information on this is included in the next section of this page.
For a more detailed Historian execution explanation, check Archiving process.
Configuring the Historian module
Configuration Workflow
The typical configuration workflow for the Historian Module has the following sequence:
| Historian module configuration workflow | ||
|---|---|---|
| Action | Where | Comments |
Define the default TagHistorian SQL Database | Historian → TargetDBs | By default, TagHistorian maps to a SQLite database named and located equal as the Solution itslef, followed by the proper FileExtension. You're able to change it as needed. |
If using Canary, modify the default target to the the Canary Historian | Historian → TargetDBs | If using Canary, a connection with the local embedded Canary Historian is already included in new solution. Just use that connection, or modify it willing to connect an external Canary System instead. |
If necessary, add other Target Databases | Historian → TargetDBs | If archiving or retrieving data from other Historian tools is necessary, such as InfluxDB or OSIsoft PI, add the connection in the Tag Providers, making sure to mark "Set as Historian Server" checkbox when creating the provider. |
Create and Edit HistorianTables | Historian → Historian Tables | Add or modify HistorianTables, organizing how the Tags will be grouped for archiving and the Target Databases. |
Add Tags to the HistorianTables | Historian → Historian Tags | Connect Tags to the Historian tables. Either by typing, browsing, pasting or any of the available import methods. |
Default TargetDB
When creating a new solution, the TagHistorian is set by default to use the embedded SQLite database provided in the Datasets module. The Historian Target Database can be chosen from a range of options, including selecting another SQL database for the Tag Historian, the Canary Historian, or any available ExternalTags Historian targets.
Historian Database options | |
|---|---|
Target Database | Description |
SQL Database | Any SQL style database, defined in the object TagHistorian on Datasets → DBs. |
Canary Historian | Embedded CanaryLabs engine included in the framework, or connection with external Canary systems. |
ExternalTags Historian (InfluxDB, OSIsoft PI) | The ExternalTags feature allows for seamless integration with third-party products, which can act as native and fully integrated historian repositories. This feature provides not only current interfaces but also allows for additional products to be easily incorporated using the driver toolkit. |
The SQLite database is suitable for databases up to around 10GB in size. If the number of tags and the save interval are expected to exceed this limit, it is recommended to use another SQL database for the Tag Historian, the Canary Historian, or any of the available ExternalTags Historian targets. It is advisable to select an alternative database option in cases where a solution is expected to create more tags or require frequent saving intervals that exceed the capabilities of the embedded SQLite database.
To configure a different SQL Database for the TagHistorian connection, please refer to the Dataset module configuration.
For other ExternalTags Historian targets, please refer to the ExternalTags configuration to define and configure their use.
Configuring HistorianTables
The Historian module creates a default HistorianTable using Dataset-TagHistorian SQL as the Target Database, with an additional HistorianTable being created if the Canary Historian is enabled. This setup offers a range of flexible options to choose from when selecting and configuring the target database for your solution's specific needs.
The HistorianTable settings allow you to define rules for saving the tags connected with it. You can set triggers such as a time deadband, specifying the minimum interval between saves, and a lifetime value, determining how long saved tag values will be retained. Note that certain options may be unavailable depending on the target database selected, so it's important to carefully consider your options.
Storing only the necessary data at the required frequency is a good practice to follow. You can use features such as deadbands, OnTagChange or Trigger events to organize your storage and save only what's required without overloading the system or slowing down data recovery.
HistorianTable configuration fields
New HistorianTables can be create with the NEW button, on Historian → Historian Tags, or editing the table on Historian → Historian Tables.
To modify History Tables, on Historian → Historian Tags, select the Table in the ComboBox and Config button, or editing the datagrid on Historian → Historian Tables.
Either using the Dialog view or datagrid view, the HistorianTable has the following configuration fields:
HistorianTable configuration properties | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Field | Description | ||||||||||||
TargetDB | Defines the Historian TargetDB. By default, SQL. Can only be changed while creating the HistorianTable. According to the Target option, some other fields on the configuration may be disabled | ||||||||||||
Table Name | Name of the HistorianTable object. For SQL databases, this name is also the table name inside the SQL DB. For other databases, this name is used as a logical grouping name.. | ||||||||||||
Auto Create | When checked, Historian module will check if this table is already created in your SQL DB. If not, a new one will be created. | ||||||||||||
Save on Change | When checked, whenever your Tags value has changed, the event to archive the tag is generated. | ||||||||||||
Trigger | Here you can define the event that triggers the archiving of all the tags in the HistorianTable group to the database. The trigger can be any tag, or any object or property from the objects namespaces. When you click on "…" ellipses button, a window will appear listing your Tags, Objects and Properties, allowing to select which one will act as a Trigger. | ||||||||||||
TimeDeadband | Enter the minimum logging interval. You must define in this format HH:MM:SS:MS (Hours, minutes, seconds, milliseconds). If left with zeros, this setting is not used. This is how long the system must wait after storing one value of a tag, before storing a new value. This field is used in conjunction with SaveOnChange option to avoid creating too many records in the database. Consider that you have a 5 seconds Deadband, the Deadband count will start when your Tag value changes. When Deadband count starts, any changes in Tag value in this range will not be saved on your DB if the time dead-end has not elapsed yet.. Your Tag’s value will only be saved in DB after TimeDeadband ends.
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Life Time | Here you can set in days how long the records will be stay on the Target Database. Every day, if the Historian Modules find data on the HistorianTables older than the lifetime, that data is automatically deleted. If its the value is 0 or blank, no automatic data deletion is executed. Data is no longer automatically deleted. | ||||||||||||
Save Quality | When checked, a column in your SQL DB store the Quality property of the Tag argon with the value. The quality level defines how much reliable is the Tag value and it follows the OPC standard specification. | ||||||||||||
Normalized | When checked, uses the Normalize table schema for SQL database, or the Standard schema otherwise. For more information on SQL database schemes refer to Archiving Process. | ||||||||||||
Value Columns Type | Select the Type for Value Columns used to store the tag values in the SQL database. This field can be edited ONLY when first creating the HistorianTable. Options:
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GetSamples Method | Name of a method defined on Script → Class to allow customization when retrieving data from this tables. | ||||||||||||
Description | Description for this HistorianTable object. | ||||||||||||
Adding Tags for Data Logging
After configuring the HistorianTables, or just keeping the predefined ones, the next step is to list the tags to be archived in connection with those HistorianTables.
Go to Historian → Historian Tags.
Type or select tags in the TagName column, or copy and paste tags from Unified Namespace → Tags.
Configure any required additional fields.
Only the TagName and TableName fields are mandatory.
HistorianItem Configuration Properties | |
|---|---|
Field / Column | Description |
TagName | Enter a tag name or click "..." to select the tag for historian archiving. |
DeadBand | When using the SaveOnChange option in the HistorianTable, the DeadBand is how much the value must change (in Units) in order to the system store the value. |
Deviation | This value can override the Time Deadband logging interval. If the tag changes more than the Deviation value, the event to archive the tag is generated, even the deadband specified in TimeDeadBand has not elapsed yet. |
DeviationDeadBandType |
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RateOfChange | This value can overrides the Time Deadband logging interval. If the Rate of Change of that is higher than this value, the event to archive the tag is generated, even the deadband specified in TimeDeadBand has not elapsed yet. The Rate of Change of a tag, is the difference on consecutive value changes, divided by the time in seconds between the changes. |
HistorianTable | Select the HistoranTable that this tag will be connected with. |
Working with the Historian module
Runtime execution
When the Solution runs, the Module Historian runs in an isolated process on the Server Computer.
The main procedures executed by the module include:
Check if a request to archive from a HistorianTable was generated (by the Trigger or OnTagChange events).
Archive the Data as needed.
Synchronize with remote archives if store and forward or redundancy is enabled.
Reply to requests from Displays and Scripts on querying the archived data.
Those procedures as described in detail in the Archiving Process page.
On this page, we have covered the essentials of the Historian module, which provides a comprehensive solution for managing time-related data in industrial equipment and systems. To further enhance your understanding and optimize the use of this module, we recommend exploring the following sections:
Monitoring Historian
It allows monitor and managing historical data storage. This functionality provides a clear view of the data and facilitates the analysis and optimization of system performance. For a comprehensive understanding, see the Monitoring HistorianTables. (Go to Historian → Historian Tables)
Displaying TrendCharts
It allows the visualization of trend charts for analysis and comparison of historical and real-time data. This functionality makes it easy to identify patterns and trends in system performance. For detailed information, see the Displaying TrendCharts.
Querying Data on Scripts
It enables the querying and retrieving of data from variables and historical tables through scripts. This functionality empowers the creation of custom logic and solution-specific analysis. For a comprehensive understanding, refer to the Querying Data on Scripts.
Troubleshooting and Best Practices
Troubleshooting and Common #Issues
The Historian module may encounter some issues in its operation. Here are some common issues and their solutions:
#Data not being archived
Check the Historian Table configuration, Trigger or TagChange settings, and Target Database. Ensure the settings are correctly set up, and the database connection is valid.
#Incomplete data
Ensure that the Historian module is started (IsStarted flag) and the archiving process is functioning correctly. Check for any error messages in the OpenStatusMessage string.
#Slow data retrieval
Enable the caching feature (EnableCache) to optimize performance when requesting large amounts of data.
#Store and Forward not working
Verify if the Store and Forward feature is enabled and configured correctly. Check the local database and target database connections.
#Database connection error
Check the database connection settings and ensure that the database is reachable.
Best Practices and #Recommendations
To ensure the smooth operation of the Historian module, follow these best practices:
#Use descriptive names for Historian objects
Use clear and descriptive names for Historian Tables, tags, and other related objects.
#Optimize data retrieval
Optimize data retrieval by enabling caching when working with large datasets.
#Ensure data integrity with Store and Forward
Use Store and Forward to ensure data integrity in case of temporary database connection issues.
#Plan your data storage strategy
Determine how much data you want to store and for how long you want to store it. It is important to plan your data storage strategy in advance so that you can optimize the historian module for your specific requirements.
#Document yours historians configurations
Document your historian module configuration to make it easier to manage and maintain. This includes documenting data sources, data types, sampling rates, storage options, and performance optimizations.
#Use security best practices
Protect the historian module from unauthorized access by implementing security best practices such as user authentication, access control, and data encryption.
Historian Runtime Attributes
The Historian namespace exposes properties and methods of the .NET objects used by the Tag Historian Module execution.
For general information on namespace and object concepts, go to the section Objects and Namespaces.
This section describes only some commonly used properties. See Namespaces Reference for the complete list of properties and available methods.
Examples of Historian properties | |||
|---|---|---|---|
Property | Type | Description | To access the property on CodeBehind |
| Boolean | This is a Boolean flag that indicates whether the Module Historian has started. If the flag is set to "true," it means that the Module Historian is up and running, actively archiving data according to the configured Historian Tables. If the flag is set to "false," the Module Historian has not yet started, and no data archiving is taking place. |
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| String | This is a string that displays a message indicating the success or failure when initiating the Module Historian. If the Module Historian starts successfully, the message will typically show "OK" or a similar confirmation. If there is an error during the initiation process, the message will display an error description to help diagnose and troubleshoot the issue. |
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| Boolean | This is a Boolean flag that, when enabled, allows the creation of temporary binary files on the server computer to optimize the performance of the TrendChart object when requesting large amounts of data. With caching enabled, the system can quickly retrieve the necessary data for the TrendChart object without causing significant delays or performance issues. By setting this flag to "true," users can benefit from improved performance and responsiveness when working with large datasets in the TrendChart object. |
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In this section: