Tags and Their Properties

Introduction

The configuration of tags fundamentally influences the behaviour and operation of Fernhill SCADA. In this topic we look at:

Tag Types

Fernhill SCADA supports a wide range of tag types. For example:

Each tag type is constructed from a number of Tag Components. For example:

The different tag types are described in detail in the Driver Documentation. Each tag type is typically documented in four sections:

Tag Folders

A Tag Folder is a container for other tags and folders.

Using the Tag Window of the Configuration Tool, you can organize tags into a hierarchy or structure that best represents a process or equipment.

Tags organized into folders

Icons are used to indicate the type of tag, for example a digital tag is indicated by the Digital Tag Icon icon, and a trend by the Trend Icon icon. Folders are indicated using the folder icon Folder Icon.

Editing Tags

The Tag Window supports these editing techniques:

Tag References

Relationships exist between tags, for example:

Tag references can be absolute or relative:

Tag reference examples:

Host TagReferenceTarget TagComment
FolderA.Tag1FolderA.Tag2FolderA.Tag2Absolute reference
FolderB.Tag1FolderA.Tag2FolderA.Tag2Absolute reference
FolderA.Tag1.Tag2FolderA.Tag2Relative reference to FolderA
FolderB.Tag1.Tag2FolderB.Tag2Relative reference to FolderB
FolderA.Tag1..FolderA.Tag3FolderA.Tag3Relative backward reference

When you rename, or move a tag, the Fernhill SCADA Server will automatically update references in other tags.

You can use the Find References tool to quickly find out which tags refer to the specified tag.

Tag Commands

A Tag Command is a command that you can execute on a tag. For example apply a force, or remove a force, or acknowledge an alarm, or send a control to a PLC.

You can execute tag commands from:

Different tag types support different sets of tag commands. Check the Driver Documentation to see which tag types support which tag commands.

Further Information

Glossary

For definitions of the terms used in Fernhill SCADA.