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Archiving Process Overview

The Historian module process to archive data is composed by 3 steps:

1. An event triggers the request to archive a group of values. There are two types of events (Trigger or TagChange) that you configure when creating a Historian Table.

2. The Historian archives the values in the Archive Location after the trigger. You can use SQL databases or a TagProvider when configuring the Archive Location.

3. If you enable the Store and Forward feature, the system executes the data synchronization. This option stores data in a local database if the configured database is unavailable and sends it to the target when it becomes available.

In the following sections, you find additional details regarding each step.

Triggering Events

In FrameworX, there are two possible actions that can iniciate the archiving process. You can configure a Trigger based on a Tag, or choose to save always the Tag's value changes using the Save on Change option.

Trigger

You have three options to define as triggers in the Historian module:

• A Tag value.
• A Tag property.
• Any object from the runtime namespace, such as Server.minute.

Whenever there's a change in the object's value, it sets creates an archive request event.

To ensure compatibility with the Historian process, Triggers are limited to Tags falling under the domain of Server or objects situated in server-side namespaces. This restriction exists because the Historian process operates exclusively on the Server computer.

You can choose one Trigger for each Historian Table. When the trigger happens, all current values of Tags and objects connected to that Historian Table will be archived, regardless of whether or not they have a new value.

Save On Change

As the Trigger, you set the Save on Change option when creating or edditing a Historian Table.

When you enable the Save on Change the Historian module verifies continuously all Tags connected to each Historian Table. As a Tag changes its value, the archive request event is generated. Only the Tag that changed its value will be arhived.

Archiving the DataSelecting the Target Database

After the archive request is created, the FrameworX system will check how the data will be stored depending on the Archive Location of the current Historian Table. You configure this option when creating the Historian Table.

The process of archeving the data will differs if you are using a SQL database or TagProvider as a Historian.

Archiving to SQL database (TagHistorian)

The Datasets Module has a pre-defined object named TagHistorian. By default, a SqlLite database is used, but you can choose other databases. Access the Historian Tables to learn how to do it.

When archiving to the SQL database defined by the TagHistorian object, you can choose between the Standard and Normalized table schemas.

Standard Tables

If you use Standard tables, both Trigger and TagChange events result in a single additional row in the database. Each column in the table corresponds to a Tag in the HistorianTable group, ensuring that all tags within the group receive an entry, even if only one tag has a new value.

The row's timestamp is determined by the Trigger object when the archive event is triggered or by the timestamp of the Tag that initiated the archive request in the case of OnTagChange events. All tags listed in the associated HistorianTable are stored, independent of whether they have new values or not, sharing a single timestamp as defined earlier. For OnTagChange events involving multiple tag value changes, a single row is inserted with all tags in the group, utilizing the timestamp of the tag that triggered the event.

Standard tables schema

The following table describes all existing columns from a Standard SQL Table contain the following columns:

You can usually assign up to 200 tags to each historian table. However, the exact number can vary depending on how many columns your target database can accommodate. As a best practice, define tags in the same table if they have similar storing rates and process dynamics.

Normalized Tables

Normalized tables archive data only after a OnTagChange events. If you check the Normalized feature when creating or editing the Historian Table, the Trigger option is disabled. 

Normalized tables store In this table schema, each one has only the TimeStamp of Tag, ID of the Tag, and the Value of Tag that generated the arquive event.

Normalized Tables Schema

The system automatically creates more four tables:

• TableName_BIT
• TableName_FLOAT
• TableName_NTEXT
• TableName_REAL

The following table describes the schemas used by the created tables.

Archiving Externally using a TagProvider

When archiving data externally using a TagProvider, the external system defines the schemas and determines the structural organization, naming conventions, and other specific settings.

Protocol

You need to specify the Protocol to add a new Archive Location using a TagProvider. The Protocol is an intermediary between the solution you build with FramewroX and the external data historian systems. They interpret and translate data formats, protocols, and other communication specifics to ensure seamless data archiving and retrieval. Currently, FrameworX provides three protocol options to connect using TagProviders:

• CanaryLabs: A robust data historian system that's optimized for real-time data collection and analytics. When archiving to CanaryLabs, the data is stored in a highly compressed format that facilitates faster retrieval and analytics.

• InfluxDB: An open-source time-series database designed for high availability and real-time analytics. InfluxDB is particularly useful when working with large sets of time-series data where timely data retrieval is of the essence.

• GE Proficy: A comprehensive platform that provides real-time data collection and advanced analytics capabilities. GE Proficy is a scalable system designed to integrate and analyze vast amounts of industrial data.

You can use the Store and Forward feature when configuring a new Archive Location using TagProvider.

Using Store and Forward

The Store and Forward feature ensures you will not lose data if the system can't connect with the external database.

When you define an Archive Locasion using a TagProvider and disable When the option to use Store and Forward is disabled, the archive requests events are sent directly to the Target Database external database as the events occurs.There is a occur, independent of an existing working connection. A built-in protection when using the exists for SQL-Dataset-TagHistorian target targets with Normalized tables. In this case, the buffering new rows are buffered and included including them in the database every 5 seconds.

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Store and Forward process

When receiving data archive requests, The Historian module will the Historian module receives an archive request, it'll try to store the data in the Target Database, and if there is a fail, it will store Archive Location. If unsuccessful, it stores the data in a local database, automatically locally created using SQLite .Every 5s, the process tries to copy database. After an unsuccessful attempt, the Historian module will attempt to copy data from the local SQLite database (the Rows rows inserted when the Target database was not accessibleinaccessible) to the the Target Database every 5 seconds, in maximum blocks of 250 rows. 

All Historian tables are verified for a maximum of 4swithin a 4-second window. If there is not enough time to process all tables are processed in time, the verification is resumed continues in the next 5 seconds -second cycle. If the copy process is successfulto the Archive Location succeeds, meaning the connection was reestablished, the copied rows are deleted removed from the temporary SQLite database, and if it is empty, the database file itself is deleted. When an application queries data, if the Target Database is not available, the system will search the cache. If the temporary SQLite database for data

This is a summary of the steps to execute the database synchronization:

• The temporary local SQLite database is accessed, checking in all tables for the NotSync column flag (not synchronized rows), with a select limit of 250.

• The result of the Selected Query (up to 250 rows) is inserted in the Target Database. 

• After successful completion of the Insert in the Target Database, the rows are deleted from local SQLite cache.

is empty after the process, it is deleted.

In applications with a high volume of data and several tables to be synchronized, the data availability in the Archive Location (external database) may take some time. The synchronization velocity depends Suppose many tables are to be synchronized with a large amount of data. In that case, the availability of this data in the main database may take some time, depending on the insertion performance of the main database and the local database databases' insertion performance (SQLite). However, after a certain period, the data will become available. On average, it takes around In most applications, the Store and Forward synchronization process takes up to 1 second per table for these steps (i) to (iii).Another important consideration is the volume of data. .

Due to the possible synchronization restrictions, it's essential to take the following points when deciding the database system to be used in your project:

• For large projects with

• significant

• data volumes, it

• 's recommended to use

• robust databases

• like SQL Server or Oracle

• for better performance

• .
• SQLite has a 10GB limit and limited performance and is suitable for smaller data models. The Keep a Local Copy feature works well for projects not requiring immediate synchronization, especially if the main database

• experiences occasional unavailability due to other projects or third-party software

• usage.

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