National Instruments BridgeVIEW 用户手册

Chapter 1 Introduction

© National Instruments Corporation 1-7 BridgeVIEW User Manual

Events

An event is something that happens within the BridgeVIEW system. 
Events can be divided into two groups: those that pertain to individual 
tags and those that pertain to the overall BridgeVIEW system. Events 
pertaining to tags include the following:

• A tag going in or out of alarm

• An operator changing the value of a tag

• An operator acknowledging an alarm

Events pertaining to the system include the following: 

• The launching or shutting down of the Engine

• A new operator logging on

• An error from a server

The Engine also maintains alarm summary and event history information 
pertaining to tags. This information can be viewed by the user’s HMI and/or 
be logged to disk.

Historical Data Logging and Extraction

You can extract data from the historical database to view the trend of tag 
data over time. The BridgeVIEW Engine manages logging data to the 
Citadel Historical Database. A 

 is a view of data over time. Trends can 

be real-time (current data) or historical (logged data). You can view logged 
data with a user interface (HMI) or with the Historical Trend Viewer 
(HTV). For more information about historical data logging and extraction 
or the Citadel Historical Database, see Chapter 6, 

, or Appendix B, 

. 

Security

Environment security is built into BridgeVIEW and determines access to 
certain parts of the BridgeVIEW environment. BridgeVIEW security is 
broken into two general categories: 

• BridgeVIEW Environment Access Privileges

• Operator Interface Security