National Instruments BridgeVIEW - Manual (Page 59)

© National Instruments Corporation 3-1 BridgeVIEW User Manual
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Tag Configuration
This chapter describes tags, the Tag Configuration Editor, how
you edit tags within the BridgeVIEW system, and includes an activity that
illustrates how to use the Tag Configuration Editor. Before you can run a
BridgeVIEW application, you must specify a tag configuration.
What Is a Tag?
A tag is a data value in the BridgeVIEW Engine. Tags can be used to
monitor an I/O point, to store a result of a calculation based on other tags,
or to monitor a tag on another BridgeVIEW Engine. A
memory tag is a tag
used for user-specified calculations, and a network tag is a tag remotely
connected to any type of tag on another BridgeVIEW Engine.
This section defines a tag in terms of its attributes and describes how tag
attributes affect Engine operations. You can define and configure tags with
the Tag Configuration Editor, described later in this chapter.
Tag Attributes
The BridgeVIEW Engine manages the Real-Time Database (RTDB) which
contains information about all the tags in the system. The Engine handles
the following tasks:
• Communicates with device servers or other BridgeVIEW Engines
• Scales tag values
• Tracks alarms and events associated with tags, system errors and
events
• Logs tag values, alarms, events and system messages to disk
You can customize these tasks by configuring each tag with the Tag
Configuration Editor. The Tag Configuration Editor displays five
categories of attributes for each tag: general information, connection,
operations, scaling, and alarms.
Operations, scaling, and alarms attributes describe how the Engine handles
a tag’s data. Each attribute can be further classified by the effect on a
running Engine from changing the attribute.