National Instruments BridgeVIEW User Manual

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User Manual

BridgeVIEW User Manual

May 1998 Edition

Part Number 321294C-01

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About This Manual

Organization of This Manual...............................................................................................xix

BridgeVIEW Concepts..........................................................................................xix

G Tutorial ...............................................................................................................xx

Appendices, Glossary, and Index..........................................................................xxi

Conventions Used in This Manual......................................................................................xxii

Related Documentation........................................... ...........................................................xxiii

Customer Communication.................................................................................................xxiii

Chapter 1 Introduction

Welcome to BridgeVIEW....................................................................................................1-1

Required System Configuration............................................................................1-2

Installation............................ .................................................................................1-2

What Is BridgeVIEW?.........................................................................................................1-3

How Does BridgeVIEW Work? ..........................................................................................1-3

G Programming.....................................................................................................1-4

Tag Configuration .................................................................................................1-5

Alarms ...................................................................................................................1-6

Events....................................................................................................................1-7

Historical Data Logging and Extraction................................................................1-7

Security..................................................................................................................1-7

What Is the BridgeVIEW System Architecture?.................................................................1-8

User HMI Application...........................................................................................1-8

BridgeVIEW Engine .............................................................................................1-9

Device Servers.......................................................................................................1-9

Where Should I Start?........................................................................................................1-10

ART

BridgeVIEW Concepts

Data Type................................................................................................1-5

General....................................................................................................1-5

Connection.............................................................................................. 1-6

Scaling.....................................................................................................1-6

Operations...............................................................................................1-6

Contents

Chapter 2 BridgeVIEW Environment

What Is G?...........................................................................................................................2-1

How Does G Work? ........................................................... .................................................2-1

Virtual Instruments ...............................................................................................2-2

Front Panel.............................................................................................. 2-2

Block Diagram........................................................................................2-3

Icon/Connector .......................................................................................2-3

Tools Palette..........................................................................................................2-4

Controls Palette.....................................................................................................2-5

Functions Palette...................................................................................................2-5

Controls and Indicators.........................................................................................2-6

Numeric ..................................................................................................2-6

Boolean...................................................................................................2-7

String ......................................................................................................2-7

Tag..........................................................................................................2-8

BridgeVIEW Environment Project Menu.........................................................................2-10

What Is the BridgeVIEW Engine Manager?.....................................................................2-12

What Are System Errors and Events?............................................................................... 2-15

What Is the Tag Browser?................................................................................................. 2-16

What Is the Tag Monitor?.................................................................................................. 2-18

How Do You Access Online Help?...................................................................................2-23

Simple/Complex Help View...............................................................................2-23

Links to Online Help Files..................................................................................2-24

Chapter 3 Tag Configuration

What Is a Tag?.....................................................................................................................3-1

Tag Attributes .......................................................................................................3-1

General Attributes................................................................................... 3-2

Connection Attributes............................................................................. 3-2

Operation Attributes ...............................................................................3-2

Scaling Attributes ...................................................... .............................3-2

Alarm Attributes.....................................................................................3-3

Static vs. Dynamic Attributes ...............................................................................3-3

BridgeVIEW User Manual vi © National Instruments Corporation

Contents

What Is the Tag Configuration Editor?................................................................................3-3

How Do You Create a Tag? ..................................................................................3-5

How Do You Edit a Tag?......................................................................................3-5

How Do You Delete a Tag? ..................................................................................3-5

What are Network Tags?.......................................................................................3-6

How Do You Add Network Tags?........................................................................3-7

How Do You Set Default Values for Tag Configuration Fields? .........................3-7

How Do You Use Spreadsheet Files for Tag Configuration?...............................3-8

How Do You Configure Tags?..........................................................................................3-10

Data Type ............................................................................................................3-10

Analog Tags..........................................................................................3-10

Discrete Tags.........................................................................................3-10

Bit Array Tags.......................................................................................3-10

String Tags............................................................................................3-11

General ................................................................................................................3-11

Connection...........................................................................................................3-12

I/O Group Configuration.......................................................................3-14

I/O Group Configuration Options...........................................3-15

Server Configuration Options.................................................3-16

Item Configuration................................................................................3-18

Item Configuration Options—Configuring

Item Names..........................................................................3-18

Item Configuration Options—Configuring

Item Resources.....................................................................3-18

What Is a Memory Tag?........................................................................3-19

When Should You Use a Memory Tag?.................................3-19

How Do You Automatically Generate Tags

from Server Information? ..................................................................3-20

How Do You Connect a Tag to an OPC Server?..................................3-21

How Do You Connect a Tag to a DDE Server? ...................................3-21

How Do You Define a Group of Tags for Alarming? ..........................3-21

Operations............................................................................................................3-22

What Is Deadband?...............................................................................3-24

How Do You Use Deadband to Increase Engine Throughput? ............3-2 4

How Do You Configure a Tag to Log Its Data or Events?...................3-25

How Do You Set Initial Tag Value at Startup? ....................................3-25

Scaling................................................................................................................. 3-25

Analog Tags..........................................................................................3-27

Example—Linear Scaling......................................................3-27

Example—Square Root Scaling ............................................3-28

How Do You Assign Units to an Analog Tag?.....................................3-28

Discrete Tags.........................................................................................3-28

Bit Array Tags.......................................................................................3-29

Contents

Alarms.................................................................................................................3-31

How Do You Configure Alarms for a Tag?.........................................3-34

What Is Alarm Deadband on Analog Tags?......................................... 3-36

How Do You Keep an Alarm Unacknowledged

after the Alarm Returns to Normal? ..................................................3-37

How Do You Configure Other Engine Parameters? ......................................................... 3-44

How Do You Turn on Historical and Event Logging at Startup?....................... 3-44

How Do You Set the File Paths for Historical and Events Files?.......................3-44

How Do You Configure Shifts?..........................................................................3-44

How Do You Configure Engine Parameters?.....................................................3-44

How Do You Launch Server Configuration Utilities

from the Tag Configuration Editor?.................................................................3-46

How Do You Access or Change Tag Configuration Information

in Your Application?......................................................................................................3-46

Chapter 4 Human Machine Interface

What Is an HMI?.................................................................................................................4-1

How Do You Build an HMI? ..............................................................................................4-2

Front Panel Objects...............................................................................................4-3

HMI G Wizard ......................................................................................................4-3

Generate the Block Diagram ..................................................................4-8

Front Panel Object and Wizard Subdiagram Association ...................... 4-8

How Do You Customize Front Panel Objects? ..................................................4-12

Control Editor.......................................................................................4-12

Importing Graphics............................................................................... 4-13

How Do You Configure Front Panel

Objects Programmatically?............................................................ .... 4-15

How Do You Monitor and Control Tags?.........................................................................4-16

Tag Data Type.....................................................................................................4-17

Tags VIs and Alarms and Events VIs................................................................. 4-20

How Do the Tags, and Alarms and Events VIs

Affect Startup/Shutdown?..................................................................4-24

Analog Tags ...........................................................................3-34

Discrete Tags..........................................................................3-35

Bit Array Tags........................................................................3-35

String Tags .............................................................................3-36

Auto Ack on Normal..............................................................3-37

User Must Ack .......................................................................3-38

BridgeVIEW User Manual viii © National Instruments Corporation

General Principles of G HMI Programming......................................................................4-25

How Do You Implement Event-Driven Programming in G?..............................4-25

How Do You Implement Polled Programming in G?.........................................4-27

How Do You Initialize and Shut Down Multiple-Loop Applications?...............4-28

How Do You Display Real-Time Trends?..........................................................4-29

How Can You Use Tag Attributes to Configure HMI Indicator

Attributes Programmatically? ..........................................................................4-31

Chapter 5 Alarms and Events

What are Alarms and Events?.............................................................................................. 5-1

Alarm States ..........................................................................................................5-1

Alarm Limit...........................................................................................................5-1

Alarm Priority........................................................................................................5-2

Alarm Summary ....................................................................................................5-2

Event History.........................................................................................................5-2

How Do You Display Alarm Summary Information?......................................................... 5-2

How Do You Display Event History Information?.............................................................5-6

How Do You Acknowledge Alarms? .................................................................................5-6

How Do You Configure Logging and Printing of Alarms and Events?............................5-10

How Do You Log Alarms and Events?...............................................................5-12

How Do You Print Alarms and Events?..............................................................5-13

How Do You View Alarms and Events?.............................................................5-14

Contents

Chapter 6 Historical Data Logging and Extraction

What Is a Trend?..................................................................................................................6-1

Real-Time Trend ...................................................................................................6-1

Historical Trend.............................................................. .......................................6-1

What Is Citadel?........................................... ........................................................................6-1

How Do You Log Historical Data? .....................................................................................6-2

How Do You Configure Historical Logging?.......................................................6-3

How Do You Extract and View Data from Historical Log Files?.......................................6-4

Historical Data VIs................................................................................................6-4

Historical Trend Viewer (HTV)............................................................................6-9

How Do You Select the Tags to Display? ............................................6-10

How Do You Change the Time Axis?..................................................6-10

Panning Buttons......................................................................6-11

Manual Changes ................................................. ... .................6-11

How Do You Change the Timespan of Data Displayed? .....................6-12

How Do You View the Value of a Tag at

a Specific Point in Time? ...................................................................6-12

Contents

How Do You Change the Y Axis? .......................................................6-12

How Do You Change the Plot Colors and Style in the Trend? ............ 6-13

How Do You Zoom In on the Trend?...................................................6-13

How Do You Export Data to a Spreadsheet?.......................................6-13

How Do You Get Online Help for the HTV?.......................................6-13

How Do You Set Tag, Time, and Color Preferences?..........................6-13

How Do You View New Data Automatically After

It Has Been Logged to Citadel?......................................................... 6-14

How Do You Incorporate the HTV into Your HMI Application? ....... 6-14

Chapter 7 Advanced Application Topics

How Do You Build an HMI with Multiple Panels?............................................................ 7-1

Front Panel Buttons...............................................................................................7-1

Panel G Wizard.....................................................................................................7-1

How Do You Use the Panel G Wizard? .................................................7-2

How Do You Configure Security with the Panel G Wizard?................. 7-3

How Do You Configure When a Button Will Be Polled?......................7-3

VI Server Functions..............................................................................................7-5

How Do You Control Panel Size?..........................................................7-6

How Do You Control Panel Visibility?.................................................. 7-7

BridgeVIEW System Control.............................................................................................. 7-7

System VIs............................................................................................................ 7-7

How Do You Start or Stop the BridgeVIEW Engine

from Your Application?........................................................ ...............7-8

How Do You Start or Stop Historical Logging from

Your Application?................................................................................7-8

How Do You Start or Stop Event Logging

from Your Application?.......................................................................7-8

How Do You Start or Stop Event Printing

from Your Application?.......................................................................7-8

Tag Attributes VIs............................... ................................................................................7-9

BridgeVIEW Security ....................................................................................................... 7-13

Environment Security ....................................... ..................................................7-13

How Do You Log In and Out? ............................................................. 7-15

How Do You Find Your Access Level?...............................................7-15

How Do You Find Your Environment Privileges? ..............................7-15

How Do You Change Your Password?................................................7-16

How Do You Check a User’s Privileges?.............................................7-16

How Do You Prompt the Operator to Log In

to Your Application? .........................................................................7-16

BridgeVIEW User Manual x © National Instruments Corporation

Chapter 8 Servers

What Are BridgeVIEW Device Servers? ............................................................................8-1

How Do You Install and Configure a Device Server?......................................................... 8-2

How Do You Use OPC Servers with BridgeVIEW?...........................................................8-5

How Do You Use DDE Servers with BridgeVIEW? ..........................................................8-9

How Do You View BridgeVIEW Server Configuration?...................................................8-9

How Do You Develop an IA Device Server?....................................................................8-12

Contents

How Do You Programmatically Log an Operator In

to Your Application?..........................................................................7-17

How Do You Programmatically Log an Operator Out

of Your Application?..................................... ... ..................................7-17

How Do You Identify the Current Operator? .......................................7-17

How Do You Restrict Access to the BridgeVIEW Environment? .......7-17

How Do You Create and Modify User Accounts? ...............................7-17

How Do You Modify the List of Available User

Access Levels?...................................................................................7-19

How Do You Export a List of Users to a File?.....................................7-19

How Do You Export Users to Another Computer

on the Network? .................................................................................7-20

How Do You Import a List of Users from a File?................................7-20

How Do You Import Users from Another Computer

on the Network? .................................................................................7-21

How Do You Modify a User’s BridgeVIEW

Environment Privileges?..................................... ...............................7-22

Operator Interface Security .................................................................................7-22

How Do You Limit User Access to HMI Objects? ..............................7-23

Installing and Configuring the NI-DAQ OPC Server ...........................................8-3

Installing and Configuring Device Servers from

the BridgeVIEW Device Servers CD.................................................................8-4

Registering Simulation Servers.............................................................................8-4

Using Remote OPC Servers ..................................................................................8-7

Registered Server Device and Item Parameters ..................................................8-11

Contents

Chapter 9 Creating VIs

What is a Virtual Instrument?.............................................................................................. 9-1

How Do You Build a VI?....................................................................................................9-1

What is a SubVI?...............................................................................................................9-12

How Do You Debug a VI?................................................................................................ 9-21

ART

G Tutorial

VI Hierarchy ....................................... ..................................................................9-1

Controls, Constants, and Indicators ......................................................................9-2

Terminals .............................................................................................................. 9-3

Wires.....................................................................................................................9-3

Tip Strips ................................................................................................9-4

Wire Stretching................................... ....................................................9-5

Selecting and Deleting Wires ................................................................. 9-5

Bad Wires ...............................................................................................9-6

VI Documentation.................................. ...............................................................9-9

Hierarchy Window..............................................................................................9-12

Search Hierarchy ..................................................................................9-14

Icon and Connector.............................................................................................9-14

Opening, Operating, and Changing SubVIs........................................................9-19

Chapter 10 Customizing VIs

Set Window Options...........................................................................................10-1

SubVI Node Setup ..............................................................................................10-1

Chapter 11 Loops and Charts

What is a Structure?...........................................................................................................11-1

Charts.................................................................................................................................11-2

Chart Modes........................................................................................................11-2

Faster Chart Updates...........................................................................................11-3

Overlaid Versus Stacked Plots............................................................................ 11-3

While Loops ......................................................................................................................11-4

Mechanical Action of Boolean Switches............................................................11-7

Timing................................................................................................................. 11-9

Preventing Code Execution in the First Iteration..............................................11-10

BridgeVIEW User Manual xii © National Instruments Corporation

Shift Registers..................................................................................................................11-11

Using Uninitialized Shift Registers...................................................................11-15

For Loops.........................................................................................................................11-20

Numeric Conversion............................................... ...........................................11-21

Chapter 12 Case and Sequence Structures and the Formula Node

Case Structure....................................................................................................................12-2

Sequence Structures...........................................................................................................12-5

Formula Node ..................................................................................................................12-11

Artificial Data Dependency .............................................................................................12-15

Chapter 13 Front Panel Object Attributes

Chapter 14 Arrays, Clusters, and Graphs

Arrays.................................................................................................................................14-1

How Do You Create and Initialize Arrays? ........................................................14-1

Array Controls, Constants, and Indicators............................................14-2

Auto-Indexing......................................................................................................14-2

Using Array Functions ........................................................................................14-9

Build Array ...........................................................................................14-9

Initialize Array.................................................................................... 1 4-10

Array Size ...........................................................................................14-11

Array Subset........................................................................................14-12

Index Array .........................................................................................14-13

Efficient Memory Usage: Minimizing Data Copies..........................................14-16

What is Polymorphism?...................................................................................................14-17

Clusters ............................................................................................................................14-17

Graphs..............................................................................................................................14-18

Customizing Graphs..........................................................................................14-18

Graph Cursors.....................................................................................14-19

Graph Axes .........................................................................................1 4-20

Data Acquisition Arrays....................................................................................14-20

Intensity Plots ..................................................................................................................14-23

Contents

Chapter 15 Application Control

What is the VI Server? ........................................................................................15-2

Contents

Chapter 16 Program Design

Use Top-Down Design......................................................................................................16-1

Make a List of User Requirements .....................................................................16-1

Design the VI Hierarchy..................................................................................... 16-1

Create the Program..............................................................................................16-3

Plan Ahead with Connector Panes ....................................................................................16-3

SubVIs with Required Inputs.............................................................................. 16-4

Good Diagram Style..........................................................................................................16-4

Watch for Common Operations..........................................................................16-4

Use Left-to-Right Layouts.................................................................................. 16-5

Check for Errors..................................................................................................16-5

Watch Out for Missing Dependencies................................................................16-7

Avoid Overuse of Sequence Structures ..............................................................16-8

Study the Examples.............................................................................................16-8

Appendix A HMI Function Reference

Appendix B Citadel and Open Database Connectivity

Appendix C Customer Communication

Glossary

Index

Figures

Figure 1-1. BridgeVIEW Architecture ..........................................................................1-8

Figure 2-1. Engine Manager Display........................................................................... 2-12

Figure 2-2. Engine Manager with System Events Displayed......................................2-14

Figure 2-3. Tag Browser Utility ..................................................................................2-16

Figure 2-4. Tag Monitor Utility ...................................................................................2-19

Figure 2-5. Status Details Dialog Box.........................................................................2-21

BridgeVIEW User Manual xiv © National Instruments Corporation

Contents

Figure 2-6. Select Tags to Monitor Dialog Box...........................................................2-22

Figure 2-7. Write to Tag dialog box.............................................................................2-22

Figure 2-8. Tag Monitor Preferences Dialog Box .......................................................2-23

Figure 3-1. Tag Configuration Editor ............................................................................3-4

Figure 3-2. Flowchart of Server/Client Interaction........................................................3-6

Figure 3-3. Select Tags for Network Import Dialog Box ..............................................3-7

Figure 3-4. General Attributes Dialog Box..................................................................3-12

Figure 3-5. Tag Connection Dialog Box......................................................................3-14

Figure 3-6. I/O Group Configuration Dialog Box ....................................................... 3-17

Figure 3-7. Tag Operations Dialog Box.......................................................................3-24

Figure 3-8. Analog Tag Scaling Dialog Box ...............................................................3-29

Figure 3-9. Scaling for Discrete Tag Configuration ....................................................3-30

Figure 3-10. Scaling for Bit Array Tag Configuration ..................................................3-31

Figure 3-11. Alarms for Analog Tag Configuration......................................................3-36

Figure 3-12. Alarms for Discrete Tag Configuration.....................................................3-37

Figure 3-13. Alarms for Bit Array Tag Configuration...................................................3-38

Figure 4-1. HMI G Wizard Dialog Box......................................................... ... .............4-6

Figure 4-2. Control Dialog Box...................................................................................4-11

Figure 4-3. Monitor Tag Value and Alarm VI.............................................................4-26

Figure 4-4. Process View Display VI ..........................................................................4-28

Figure 4-5. Two Trend Display VI ..............................................................................4-30

Figure 4-6. Initializing the Waveform Chart Indicator

for a Real-Time Trend Display .................................................................4-30

Figure 4-7. Using the Tag Attributes VIs to Initialize

Front Panel Indicators, Frame 0 ................................................................4-32

Figure 4-8. Using the Tag Attributes VIs to Initialize

Front Panel Indicators, Frame 1 ................................................................4-33

Figure 5-1. Event Configuration Dialog Box...............................................................5-10

Figure 6-1. Historical Logging Configuration Dialog Box............................................6-3

Figure 6-2. Historical Trend Viewer..............................................................................6-9

Figure 6-3. Select Tags Dialog Box.............................................................................6-10

Figure 7-1. Panel G Wizard ...........................................................................................7-2

Figure 7-2. Access Levels Dialog Box ........................................................................7-14

Figure 7-3. Privileges Dialog Box ...............................................................................7-15

Figure 7-4. Edit User Accounts Dialog Box ................................................................7-17

Figure 7-5. Add a User Account..................................................................................7-17

Figure 7-6. Using the Security Monitor VI to Control Visibility ................................7-22

Contents

Tables

Figure 8-1. Server Browser............................................................................................8-6

Figure 8-2. View Server Information Dialog Box.........................................................8-7

Figure 8-3. Browse OPC Servers on Network Dialog Box...........................................8-8

Figure 8-4. Server Browser..........................................................................................8-11

Figure 8-5. View Server Information Dialog Box.......................................................8-12

Table 2-1. BridgeVIEW Project Menu Items ............................................................2-10

Table 2-2. Engine Manager Field Descriptions .........................................................2-13

Table 2-3. Tag Browser Field Descriptions ..............................................................2-17

Table 2-4. Tag Monitor Utility Field Descriptions ...................................................2-20

Table 3-1. General Configuration Attributes ............................................................ 3-12

Table 3-2. Connection Configuration Attributes .......................................................3-15

Table 3-3. I/O Group Configuration Attributes .........................................................3-17

Table 3-4. Operations Configuration Attributes ........................................................3-25

Table 3-5. Scaling Configuration Attributes .............................................................3-27

Table 3-6. Bit Array Scaling Examples...................................................................... 3-32

Table 3-7. Alarms Configuration Attributes ............................................................3-33

Table 3-8. Events with Alarm Deadband = 0.0% ......................................................3-38

Table 3-9. Events with Alarm Deadband = 1.0% ......................................................3-39

Table 3-10. Configuration Settings for Activity 3-1 ................................................... 3-42

Table 3-11. Configuration Modifications for Activity 3-1...........................................3-43

Table 3-12. Configurable Memory Allocation Parameters ......................................... 3-47

Table 4-1. HMI G Wizard Operations .........................................................................4-4

Table 5-1. Tag Configuration Editor Event Configuration Selections ......................5-10

Table 5-2. Event Configuration, Log, and Print Format Selections ..........................5-12

Table 6-1. Parameters You Can Configure for Historical Logging ............................ 6-3

Table 6-2. Panning Button Functions.........................................................................6-11

Table 7-1. BridgeVIEW Environment Privileges ....................................................7-12

Table 7-2. Abbreviations Used to Enable Privileges for a User ...............................7-19

Table B-1. Data Transform Commands .......................................................................B-5

BridgeVIEW User Manual xvi © National Instruments Corporation

Activities

Activity 2-1. Open and Run a VI......................................................................................2-8

Activity 3-1. Configure a Tag, and View the Tag Configuration

Activity 4-1. Use the HMI G Wizard ...............................................................................4-8

Activity 4-2. Import a Graphic Image into BridgeVIEW...............................................4-13

Activity 4-3. Read a Tag .................................................................................................4-20

Activity 5-1. Build an Alarm Summary Display..............................................................5-3

Activity 5-2. Acknowledge Alarms in the Alarm Summary Display...............................5-7

Activity 6-1. Use the Historical Data VIs.........................................................................6-6

Activity 6-2. Use the Historical Trend Viewer...............................................................6-15

Activity 7-1. Use the Panel G Wizard ..............................................................................7-3

Activity 7-2. Use Tag Attributes.....................................................................................7-10

Activity 7-3. Apply Security to the Alarm Summary Display .......................................7-23

Activity 9-1. Create a VI...................................................................................................9-6

Activity 9-2. Document a VI ..........................................................................................9-10

Activity 9-3. Create an Icon and Connector...................................................................9-16

Activity 9-4. Call a SubVI..............................................................................................9-19

Activity 9-5. Debug a VI in BridgeVIEW......................................................................9-21

Contents

Parameters and Tag Values.......................................................................3-40

Activity 10-1. Use Setup Options for a SubVI .................................................................10-2

Activity 11-1. Experiment with Chart Modes .................................................................11-3

Activity 11-2. Use a While Loop and a Chart .................................................................11-4

Activity 11-3. Change the Mechanical Action of a Boolean Switch...............................11-8

Activity 11-4. Control Loop Timing................................................................................11-9

Activity 11-5. Use a Shift Register................................................................................11-13

Activity 11-6. Create a Multiplot Chart and Customize Your Trends...........................11-17

Activity 11-7. Use a For Loop.......................................................................................11-22

Activity 12-1. Use the Case Structure .............................................................................12-2

Activity 12-2. Use a Sequence Structure.........................................................................12-5

Activity 12-3. Use the Formula Node............................................................................12-13

Activity 14-1. Create an Array with Auto-Indexing........................................................14-3

Activity 14-2. Use Auto-Indexing on Input Arrays.........................................................14-7

Activity 14-3. Use the Build Array Function ................................................................14-15

Activity 14-4. Use the Graph and Analysis VIs ............................................................14-20

About This Manual

The BridgeVIEW User Manual contains the information you need to get

started with the BridgeVIEW software package. This manual explains the

BridgeVIEW environment, tag configuration, human machine interfaces,

alarms and events, and historical data logging and extraction. This manual

also reviews the concepts of G programming.

Throughout both sections of this manual, there are activities that teach

you what you need to know to build your own virtual instruments, and

ultimately, your own SCADA system. This manual assumes that you

know how to operate your computer and that you are familiar with its

operating system.

Organization of This Manual

This manual is divided into two parts. Part I, BridgeVIEW Concepts,

introduces you to the basic BridgeVIEW concepts, and includes Chapters 1

through 8. Part II, G Tutorial, describes the G programming language, and

how it works within BridgeVIEW, and includes Chapters 9 through 15.

We encourage you to work through all the activities in this manual before

you begin building your applications. You should save all of the VIs you

create with the BridgeVIEW activities in the

directory. To view the VI(s) for an activity that you have not completed

yourself, see the

solutions to the activities from the BridgeVIEW Concepts section of this

manual, and the

solutions to the activities in the G Tutorial section of this manual.

BridgeVIEW\Activity\Solutions

BridgeVIEW\Activity\Solution

BridgeVIEW\Activity

directory for the

BridgeVIEW Concepts

Part I, BridgeVIEW Concepts, contains the following chapters.

• Chapter 1, Introduction, describes the unique BridgeVIEW approach to Human Machine Interface (HMI) and Supervisory Control and Data Acquisition (SCADA). It also contains system configuration, installation instructions and basic information that explains how to start using BridgeVIEW to develop industrial automation applications.

• Chapter 2, BridgeVIEW Environment, describes the BridgeVIEW environment. It explains the basic concepts behind G, the

About This Manual

programming language upon which BridgeVIEW is built, the BridgeVIEW Engine Manager, system errors and events, the Tag Monitor utility, and the Tag Browser utility. This chapter also explains how to access online help for BridgeVIEW and provides an activity that illustrates how to examine the front panel and block diagram of a virtual instrument (VI).

• Chapter 3, Tag Configuration, explains tags, the Tag Configuration Editor, and how you edit tags within the BridgeVIEW system.

• Chapter 4, Human Machine Interface, explains what a Human Machine Interface (HMI) is and how you can monitor and control tags from your HMI.

• Chapter 5, Alarms and Events, introduces the basic concepts of alarms and events, and explains how to view, acknowledge, and configure them within the BridgeVIEW system.

• Chapter 6, Historical Data Logging and Extraction, explains the concept of a trend, how to log and extract historical data, and how to use the Historical Trend V iewer (HTV), a utility that displays historical data that has been logged to disk with BridgeVIEW.

• Chapter 7, Advanced Application Topics, explains the advanced topics you need to understand to make optimum use of BridgeVIEW for developing applications. The advanced topics covered in this chapter are the Panel G Wizard, BridgeVIEW System Control, Tag Attributes VIs, and BridgeVIEW Security.

• Chapter 8, Servers, explains how to use servers with BridgeVIEW. BridgeVIEW supports several types of servers including OPC Serv ers, DDE Servers, and IA Device Servers.

G Tutorial

Part II, G Tutorial, contains the following chapters.

• Chapter 9, Creating VIs, introduces the basic concepts of virtual instruments and provides activities that explain how to create the icon and connector, how to use a VI as a subVI, ho w to use the VI Setup… option, and how to use the SubVI Node Setup… option.

• Chapter 10, Customizing VIs , introduces the basic concepts used for customizing VIs.

• Chapter 11, Loops and Charts, introduces structures and explains the basic concepts of charts, the While Loop, and the For Loop.

BridgeVIEW User Manual xx © National Instruments Corporation

• Chapter 12, Case and Sequence Structures and the Formula Node, introduces the basic concepts of Case and Sequence structures, and provides activities that explain how to use the Case structure, how to use the Sequence structure, and what sequence locals are and how to use them.

• Chapter 13, Front Panel Object Attributes, describes objects called attribute nodes, which are special block diagram nodes that control the appearance and functional characteristics of controls and indicators.

• Chapter 14, Arrays, Clusters, and Graphs, introduces the basic concepts of polymorphism, arrays, clusters, and graphs and provides activities that explain auto-indexing and the Graph and Analysis VIs.

• Chapter 15, Application Control, introduces the VI Server and provides an activity that explains how to use it within BridgeVIEW. The VI Server allows you to control when a VI is loaded into memory, run, and unloaded from memory.

• Chapter 16, Program Design, suggests some techniques to use when creating programs and offers programming style recommendations.

Appendices, Glossary, and Index

• Appendix A, HMI Function Reference, describes error handling for BridgeVIEW VIs and contains an explanation of the VIs in the BridgeVIEW VI library. In this appendix, the VIs are arranged alphabetically, first by VI Library name (Alarms and Events, Historical Data, System, Tags, and Tag Attributes), then by VI name.

• Appendix B, Citadel and Open Datab ase Connectivity, describes the Citadel database and the Open Database Connectivity (ODBC) driver , and includes several examples of how to use it.

• Appendix C, Customer Communication, contains forms to help you gather the information necessary to help us solve your technical problems, and a form you can use to comment on the product documentation.

• The Glossary contains an alphabetical list of terms used in this manual, including abbreviations, acronyms, metric prefixes, mnemonics, and symbols.

• The Index contains an alphabetical list of key terms and topics in this manual, including the page where you can find each one.

About This Manual

Conventions Used in This Manual

The following conventions are used in this manual:

bold Bold text denotes a parameter, menu name, palette name, menu item,

return value, function panel item, or dialog box button or option.

italic Italic text denotes mathematical variables, emphasis, a cross reference,

or an introduction to a key concept.

bold italic Bold italic text denotes an activity objective, note, caution, or warning.

monospace

monospace bold

monospace italic

<> Angle brackets enclose the name of a key on the keyboard—for example,

- A hyphen between two or more key names enclosed in angle brackets

<Control> Key names are capitalized. » The » symbol leads you through nested menu items and dialog box options

Text in this font denotes text or characters that you should literally enter from the keyboard. Sections of code, programming examples, and syntax examples also appear in this font. This font also is used for the proper names of disk drives, paths, directories, programs, subprograms, subroutines, device names, variables, filenames, and extensions, and for statements and comments taken from program code.

Bold text in this font denotes the messages and responses that the computer automatically prints to the screen. This font also emphasizes lines of code that are different from the other examples.

Italic text in this font denotes that you must enter the appropriate words or values in the place of these items.

<PageDown>.

denotes that you should simultaneously press the named keys—for example, <Control-Alt-Delete>.

to a final action. The sequence File»Page Setup»Options»Substitute Fonts directs you to pull down the File menu, select the Page Setup item, select Options, and finally select the Substi tute Fonts option from the last dialog box.

paths Paths in this manual are denoted with backslashes (\) to separate drive

names, directories, and files, as in

BridgeVIEW User Manual xxii © National Instruments Corporation

C:\dir1name\dir2name\filename

This icon to the left of bold text denotes the beginning of an activity, which contains step-by-step instructions you can follow to learn more about BridgeVIEW.

This icon to the left of bold text denotes the end of an activity, which contains step-by-step instructions you can follow to learn more about BridgeVIEW.

This icon to the left of bold italicized text denotes a note, which alerts you to important information.

Abbreviations, acron yms, metric pref ixes, mnemonics , symbols, and terms are listed in the Glossary.

Customer Communication

National Instruments wants to receive your comments on our products and manuals. We are interested in the applications you develop with our products, and we want to help if you have problems with them. To make it easy for you to contact us, this manual contains comment and configuration forms for you to complete. These forms are in Appendix C, Customer

Communication, at the end of this manual.

BridgeVIEW Concepts

This section contains information about the BridgeVIEW environment, tag configuration, Human Machine Interface, alarms and events, historical data logging and extraction, servers, and advanced application topics such as system control and security.

Part I, BridgeVIEW Concepts, contains the following chapters.

• Chapter 1, Introduction, describes the unique BridgeVIEW approach to Human Machine Interface (HMI) and Supervisory Control and Data Acquisition (SCADA). It also contains system configuration, installation instructions and basic information that explains how to usestart using BridgeVIEW to develop industrial automation applications.

• Chapter 2, BridgeVIEW Environment, describes the BridgeVIEW environment. It explains the basic concepts behind G, the programming language upon which BridgeVIEW is built, the BridgeVIEW Engine Manager, system errors and even ts, th e Tag Monitor utility, and the Tag Browser utility. This chapter also explains how to access online help for BridgeVIEW and provides an activity that illustrates how to examine the front panel and block diagram of a virtual instrument (VI).

• Chapter 3, Tag Configuration, explains tags, the Tag Configuration Editor, and how you edit tags within the BridgeVIEW system. Before you can run a BridgeVIEW application, you must specify a tag configuration.

• Chapter 4, Human Machine Interface, explains what a Human Machine Interface (HMI) is and how you can monitor and control tags from your HMI.

• Chapter 5, Alarms and Events, introduces the basic concepts of alarms and events, and explains how to view, acknowledge, and configure them within the BridgeVIEW system.

Part I

Part I BridgeVIEW Concepts

• Chapter 7, Advanced Application Topics, explains BridgeVIEW Environment Securitythe advanced topics you need to understand to make optimum use of BridgeVIEW for developing applications. The advanced topics covered in this chapter are the Panel G Wizard, BridgeVIEW System Control, Tag Attributes VIs, and BridgeVIEW Security.

• Chapter 8, Servers, explains how to use servers with BridgeVIEW. BridgeVIEW supports several types of servers including OPC Serv ers, DDE Servers, and IA Device Servers.

BridgeVIEW User Manual I-2 © National Instruments Corporation

Introduction

This chapter describes the unique BridgeVIEW approach to

Human Machine Interface (HMI) and Supervisory Control and Data

Acquisition (SCADA). It also contains system configuration, installation instructions, and basic information that explains how to start using BridgeVIEW to develop industrial automation applications. This chapter refers you to other chapters or manuals for more information.

Welcome to BridgeVIEW

BridgeVIEW adds real-time process monitoring, historical trending, alarm and event reporting, online configuration tools and PLC connectivity to a premiere graphical development environment, G.

BridgeVIEW makes use of an intuitive graphical user interface combined with a powerful graphical programming language, G, that enables you to perform data acquisition and analysis, create an operator interface or Human Machine Interface (HMI), and develop adv anced supervisory control applications.

BridgeVIEW provides the following features for the development of your Industrial Automation applications.

• Graphical human-machine interface (HMI)

• Easy-to-use, fill in the blank configuration utilities

• Graphical programming tools

• Real-Time Database (RTDB)

• Historical data collection and trending (Citadel)

• Alarm and event reporting and logging

• Security

• Connectivity to PLC and industrial device networks

• OPC Server Support

Chapter 1 Introduction

Required System Configuration

BridgeVIEW is distributed on a CD-ROM that includes the complete BridgeVIEW 2.0 release.

The Windows 95/NT version of BridgeVIEW runs on any system that supports Windows 95 or W indows NT 4.0. A minimum of 24 MB of RAM is required for this version to run effectively. We recommend 32 MB of RAM and at least 30 MB of swap space available on your system.

Note

Installation

The standard BridgeVIEW installation requires approximately 110 MB of disk space. A full installation requires approximately 150 MB. If you plan to install the NI-DAQ Server as well, an additional 30 MB of disk space is required.

Complete the following steps to install BridgeVIEW.

1. Insert the CD in your CD-ROM drive.

2. Run the BridgeVIEW installer. a. If you have Windows 95 or Windows NT 4.0 and your system

uses the AutoPlay feature, the Welcome to BridgeVIEW screen appears a short time after you insert the CD.

b. If you have a system not using AutoPlay, run the following

program:

:\bvsetup.exe

where

is the letter of your CD-ROM drive.

3. Choose an installation. The installer offers several installation types: Standard, Full, Minimum, and Custom. The Standard installation requires approximately 110 MB. The Full installation, which also includes Data Acquisition, GPIB, and VISA libraries and examples, requires approximately 150 MB of disk space. The Standard installation is recommended.

4. After selecting an installation, follow the instructions that appear on your screen.

Note

If you plan to use National Instruments Data Acquisition (DAQ) devices, VISA, or GPIB instrumentation, you can perform either the Full installation, which installs all necessary drivers and example programs, or the Custom installation, in which you select the items to install.

After you have installed BridgeVIEW completely, it is ready to run. You migh t need to re-boo t your machine after installation so that updated system, DAQ, VISA, or GPIB drivers can be loaded properly.

BridgeVIEW User Manual 1-2 © National Instruments Corporation

What Is BridgeVIEW?

BridgeVIEW is a software package specifically targeted at industrial automation applications. BridgeVIEW provides configurable solutions for common HMI and SCADA functions while leveraging the flexibility of graphical programming. BridgeVIEW is built around the Gprogramming language, created by National Instruments Corporation.

With BridgeVIEW, you can acquire data and control one or more distributed devices in an overall facility. BridgeVIEW can change set points or send control instructions to the individual devices while monitoring the entire system. It also can gather information like alarms and measurement points from these devices.

Common devices used for data acquisition include Programmable Logic Controllers (PLCs), plug-in Data Acquisition boards, and other distributed Input/Output (I/O) modules. BridgeVIEW device servers communicate with these non-plug-in devices through RS-232, RS-485, TCP/IP, DDE, netDDE, direct I/O, or other proprietary interfaces. BridgeVIEW device servers provide the necessary protocol software to communicate with thesedevices. BridgeVIEW also operates directly with OPC servers.

Chapter 1 Introduction

How Does BridgeVIEW Work?

BridgeVIEW uses a combination of tags, events, and data. A tag is a connection to a real-world I/O point, while an event is anything that happens to a tag or to the BridgeVIEW Engine in general. The BridgeVIEW Engine communicates with device servers on one end, andwith your HMI application at the other end. The BridgeVIEW Enginemaintains a Real-Time Database (RTDB) of tag information and logs historical data and events. You can build your HMI to interface with the BridgeVIEW Engine using virtual instruments (VIs) to read and write tag values, view alarm information and trend data. A virtual instrument is a BridgeVIEW function, written in the graphical programming language G. For more information about G, see any of the chapters in the G Tutorial section of this manual.

Start by configuring all the tags in your system with the Tag Configuration Editor. Then, you can launch the BridgeVIEW Engine, which reads your configuration file and starts monitoring tags, logging data and events. You can create your HMI application to display tag values, trends, and alarms. You also can acknowledge alarms and control output tags. You can build the HMI using BridgeVIEW VIs to read and write tag values, view alarm

Chapter 1 Introduction

G Programming

information, acknowledge alarms, view real-time trends and retrieve historical data. For more information about how to get started with BridgeVIEW, see the Where Should I Start? section at the end of this chapter.

G is the easy-to-use graphical data flow programming language BridgeVIEW is based upon. G simplifies scientific computation, processmonitoring and control, test and measurement, and a wide varietyof other applications.

G was first introduced by National Instruments as the programming language behind LabVIEW, the program development application used commonly for test and measurement purposes. BridgeVIEW has taken all the functionality of G and enhanced it for your industrial automation needs.

The G Tutorial section of this manual covers the functionality of G that you need to get started with most BridgeVIEW applications. For a more extensive explanation of BridgeVIEW functionality, see the GProgramming Reference Manual.

The basic concepts of G that are covered in this manual are as follows:

• VIs—Virtual instruments (VIs) have three main parts: the front panel, the block diagram, and the icon/connector. The front panel specifies the user interface of the VI. The block diagram consists of the executable code that you create using nodes, terminals, and wires. With the icon/connector, you can use a VI as a subVI in the block diagram of another VI. For more information about VIs, refer to Chapter9, CreatingVIs, and Chapter10, Customizing VIs.

• Loops and Charts—G has two structures to repeat execution of a sub-diagram—the While Loop and the For Loop. Both structures are resizable boxes. You place the subdiagram to be repeated inside the border of the loop structure. The While Loop executes as long as the value at the conditional terminal is TRUE. The For Loop executes a set number of times. Charts are used to display real-time trend information to the operator. For more information about loops and charts, refer to Chapter11, Loops and Charts.

• Case and Sequence Structures—The Case structure is a conditional branching control structure, which executes a subdiagram based on certain input. sequence structure is a program control structure that executes its subdiagrams in numeric order. For more information about Case or Sequence structures, refer to Chapter12, Case and Sequence

Structures and the Formula Node.

BridgeVIEW User Manual 1-4 © National Instruments Corporation

Tag Configuration

Chapter 1 Introduction

• Attribute Nodes—Attribute nodes are special block diagram nodes that you can use to control the appearance and functional characteristics of controls and indicators. For more information about attribute nodes, refer to Chapter13, Front Panel Object Attributes.

• Arrays, Clusters and Graphs—An array is a resizable collection of data elements of the same type. A cluster is a statically sized collection of data elements of the same or different types. Graphs commonly are used to display data. For more information about arrays, clusters, and graphs, refer to Chapter14, Arrays, Clusters, and Graphs.

• VI Server—The VI Server allows you to control when a VI is loaded into memory, run, and unloaded from memory. For more information about VI Control VIs, refer to Chapter15, Application Control.

A tag value is acquired and/or controlled by a device server that communicates with the BridgeVIEW Engine and can be read or set by aVIin your HMI application. Tags can be of the following types: input, output, Input/Output, or memory. You can configure tags through the TagConfiguration Editor. A tag configuration consists of its data type, connection, scaling, operations, and alarms settings. For more information about this topic, refer to Chapter3, Tag Configuration.

Data Type

A tag datatype can be analog, discrete, bit array, or string. Analog tags have continuous values with a specified range (such as 0.0 to 100.0). Discrete tags have values that are either ON (1) or OFF (0). Bit array tags are comprised of up to 32 bits, each of which can have an ON (1) or OFF(0) state. String tags consist of ASCII characters or binary data and can be of any length.

General

General includes the following tag attributes:

•Tag name

• Tag description

• Tag group

• Length (for bit array and string tags)

Chapter 1 Introduction

Connection

Connection includes the following tag attributes:

• Access rights (input only, output only, Input/Output, or memory)

•Server name

• I/O group name

• Item name

• Access path (for OPC servers)

Scaling

Scaling controls the type of scaling to perform on a tag when communicating with a device server, and the expected engineering rangeand units for the tag.

Operations

You can specify how the BridgeVIEW Engine updates the Real-Time

Database (RTDB), when it logs the tag data to disk, if it logs events

associated with the tag, and what value exists in the database at startup. Theoperations that can be performed on a tag are as follows:

• Updating the Real-Time Database

• Historical logging

• Event logging

• Event printing

Alarms

An alarm is an abnormal process condition. For example, an analog tagcanbe configured to be in a HI alarm state when its value is greater than25.You can set alarm limits for a tag in the Tag Configuration Editor. Each alarm limit has a priority associated with it to determine the severity of the alarm.

BridgeVIEW User Manual 1-6 © National Instruments Corporation

Events

An event is something that happens within the BridgeVIEW system. Events can be divided into two groups: those that pertain to individual tagsand 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 trend 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 Chapter6, Historical Data Logging

andExtraction, or AppendixB, Citadel and Open Database Connectivity.

Chapter 1 Introduction

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

Chapter 1 Introduction

What Is the BridgeVIEW System Architecture?

The BridgeVIEW system contains three sets of processes: the user HMI Application, the BridgeVIEW Engine, and industrial automation device servers, as shown in Figure 1-1. These processes interact through a client-server relationship.

HMIs

Real-Time Database

Servers

PLC DAQ OPC Other (including DDE)

Figure 1-1.

VIs

User HMI Application

The end user of the BridgeVIEW system sees and interacts with an HMI. The HMI application is a collection of VIs that you build with the G programming language in BridgeVIEW. You build VIs that interact

BridgeVIEW User Manual 1-8 © National Instruments Corporation

BridgeVIEW Engine

Chapter 1 Introduction

withthe BridgeVIEW Engine to read and write tag values, acknowledge alarms, access historical data, and read and write tag attributes.

BridgeVIEW makes development of operator graphic displays easy and fast. Floating palettes provide controls and functions necessary to develop effective HMI and SCADA applications. The Controls palette provides a number of predefined objects, selected from the automation symbol library, for building your HMI. The Functions palette provides a set of functions and VIs you can use for I/O, analysis, historical data, and networking.

The BridgeVIEW Engine is the heart of the BridgeVIEW System. It runs as a separate process, independent of your HMI application. This minimizes interference between the Engine and your HMI. The BridgeVIEW Engine maintains the Real-Time Database of all tag values and alarm states. It reads values from the various device servers. These values are scaled and compared with their alarm limits. If a tag is in an alarm state, the Engine generates appropriate events and logs them to disk.

The Real-TimeDatabase (RTDB) is an in-memory snapshot of the state of all tags in the system. If a tag value changes more than its update deadband, or its alarm state changes, the RTDB is updated. Along with tag values, the RTDB also stores status, date, time, and alarm information.

Device Servers

A device server is the application that communicates with the I/O devices such as PLCs and plug-in cards. Several National Instruments device servers are written to a National Instruments standard client/server Application Programming Interface (API) for the BridgeVIEW Engine.BridgeVIEW also communicates with OPC and DDE Servers. There aredifferent servers for different device manufacturers and communication networks.

The device servers that support the BridgeVIEW Engine are stand-alone programs launched by the BridgeVIEW Engine, and thereafter run in the background, reading selected input items and writing them on demand. Each server either is configured by BridgeVIEW when tags are created, orhas a specific configuration utility that determines communication parameters, I/O poll rates, and device addresses. A server completes operation only when the BridgeVIEW Engine shuts down.

Input items are polled by servers at a rate determined by the BridgeVIEW I/O groupconfiguration. For each input item, the device server passes

Chapter 1 Introduction

the value, the timestamp of when the item was sampled, and status information to the BridgeVIEW Engine. Output items are written on demand only when the BridgeVIEW Engine passes a new output value to the server.

The device server monitors the items and encapsulates all device and hardware-specific details, thereby providing a hardware- and software-independent layer to the user HMI and SCADA application. For more information about device servers, see Chapter 8, Servers.

Where Should I Start?

The following table lists what is included in the different installation types.

Installation

Type

Minimum Ta g Configuration Editor, basic security tools,

Standard Ta g Configuration Edito r, all security tools,

Includes

core VI libraries

Historical Trend Viewer, Tag Browser, Tag Monitor, core VI libraries, adva nced analysis libraries, online help, activities, and graphics files

Full Ta g Configuration Edito r, all security tools,

Historical Trend Viewer, Tag Browser, Tag Monitor, core VI libraries, advanced analysis libraries, online help, activities, graphics files, Instrument Wizard, DAQ, GPIB, and VISA libraries

Custom Select which utilities and libraries to install.

We recommend that you work through the activities in this manual. These activities comprehensively illustrate how BridgeVIEW works. If you are new to the G pro gramming lan guage, begin with the activities in Chapters 9 through 16, and then continue with those in Chapters 2 through 8. If you are an experienced G programmer, begin with Chapter 2 and continue through the entire manual so that you might learn the important BridgeVIEW concepts, and review any G programming techniques that you might be familiar with already.

Save all of the VIs you create with the BridgeVIEW activities in the

BridgeVIEW\Activity

BridgeVIEW User Manual 1-10 © National Instruments Corporation

directory. There is also a Solution directory

Chapter 1 Introduction

BridgeVIEW\Activity\Solutions

(

) that contains the completed VIs for each activity in this manual. You can view the VI for an activity that you have not completed yet, or use the VIs in this directory as a means of verifying your work.

Another good place to start is the Examples

readme.vi

, at the top level of this directory, to browse through the

directory. Use the VI called

available examples. If you are going to use device servers, including OPC servers, read

Chapter 8, Servers, which contains important information about servers, including what you need to develop your own device servers.

BridgeVIEW Environment

This chapter describes the BridgeVIEW environment. It explains thebasicconcepts behind G, the programming language upon which BridgeVIEW isbuilt, the BridgeVIEW Engine Manager, system errors andevents, the Tag Monitor utility, and the Tag Browser utility. This chapter also explains how to access online help for BridgeVIEW and provides an activity that illustrates how to examine the front panel andblock diagram of a virtual instrument (VI).

What Is G?

G is a programming language, much like various commercial C or BASIC development languages. However, G is different from those applications inone important respect. Other programming languages are text-based languages that create lines of code, while G is a graphical programming language that creates programs in block diagram form.

You can use G with little programming experience. G engineers and programmers rely on graphical symbols and data flow rather than textual language to describe programming actions. Data flow is a programming system in which nodes execute when they have received all required input data, and produce output automatically when they have executed.

G has extensive libraries of functions and subroutines for most programming tasks. BridgeVIEW includes conventional program development tools for G, so you can set breakpoints, animate program execution to see how data passes through the program, and single-step through the diagram to make debugging and program development easier.

How Does G Work?

G includes libraries of functions and development tools designed specifically for HMI development, data acquisition, and instrument control. G programs are called virtual instruments (VIs) because their appearance and operation imitate actual instruments. However, they are analogous to functions in conventional programming languages.

Chapter 2 BridgeVIEW Environment

Virtual Instruments

VIs have both an interactive user interface and a source code equivalent, and accept parameters from higher-level VIs. VIs have three main parts:

• The front panel

• The block diagram

• The icon/connector With these features, G promotes and adheres to the concept of modular

programming. You divide an application into a series of tasks, which youcan divide again until a complicated application becomes a series ofsimple subtasks. You build a VI to accomplish each subtask and then combine those VIs on another block diagram to accomplish the larger task. Finally, your top-level VI contains a collection of subVIs that represent application functions.

Because you can execute each subVI by itself, apart from the rest of the application, debugging is much easier. Furthermore, many low-level subVIs often perform tasks common to several applications, so you can develop a specialized set of subVIs and reuse them in different applications.

For more information about VIs, see Chapter9, CreatingVIs, and Chapter10, Customizing VIs, in this manual, or refer to the GProgramming Reference Manual.

Front Panel

VIs contain an interactive user interface, which is called the front panel, because it simulates the panel of a physical device. The front panel can contain knobs, push buttons, graphs, and other controls and indicators. Youinput data using a keyboard, mouse, touch screen, or other device andthen view the results on the computer screen.

The front panel contains a toolbar of command buttons and status indicators that you use for running and debugging VIs. It also contains font options and alignment and distribution options for editing VIs. Pictures of the front panel toolbar, and its buttons, are shown below.

Run button—Runs the VI. Continuous Run button—Runs the VI over and over; useful for

debugging.

BridgeVIEW User Manual 2-2 © National Instruments Corporation

Chapter 2 BridgeVIEW Environment

Stop button—Aborts VI execution. Pause/Continue button—Pauses VI execution/Continues VI execution. Font ring—Sets font options, including font type, size, style, and color. Alignment ring—Sets alignment options, including vertical, top edge, left,

and so on, for two or more objects. Distribution ring—Sets distribution options, including gaps,

compression, and so on, for two or more objects. Reorder ring—Allows you to restack overlapping objects by moving a

selected object above or below the others.

Block Diagram

VIs are executed from a block diagram, which you construct in G. The block diagram supplies a pictorial solution to a programming problem. Theblock diagram contains the source code for the VI.

The block diagram toolbar contains additional options that are not included on the front panel toolbar. Use these additional options for debugging VIs. The block diagram toolbar is shown below.

Highlight Execution button—Displays data as it passes through wires.

Step Into button—Steps into loops, subVIs, and so on.

Step Over button—Begins single stepping, steps over a loop, subVI,

andso on. Step Out button—Completes execution of loops, VIs, block diagrams,

andso on.

Icon/Connector

VIs use a hierarchical and modular structure. You can use them as top-level programs, or as subprograms within other programs. A VI within another VI is called a subVI. The icon/connector pane of a VI works like a graphical parameter list so that other VIs can pass data to it as a subVI.

Chapter 2 BridgeVIEW Environment

Tools Palette

BridgeVIEW has a floating Tools palette, which you can use to edit and debug VIs. You use the <Tab> key to tab through the commonly used tools on the palette. If you have closed the Tools palette, select Windows»Show Tools Palette to display the palette. A shortcut for bringing up the Tools palette is to right click while pressing the <Shift> key. The following illustration shows the Tools palette.

Operating tool—Places Controls and Functions palette items on the front panel and block diagram.

Positioning tool—Positions, resizes, and selects objects. Labeling tool—Edits text and creates free labels.

Wiring tool—Wires objects together in the block diagram. Object pop-up menu tool—Brings up a pop-up menu for an object.

Scroll tool—Scrolls through the window without using the scrollbars.

Breakpoint tool—Sets breakpoints on VIs, functions, loops, sequences, and cases.

Probe tool—Creates probes on wires. Color Copy tool—Copies colors for pasting with the Color tool. Color tool—Sets foreground and background colors.

Note

BridgeVIEW User Manual 2-4 © National Instruments Corporation

You can pop up on an object by clicking on it with the right mouse button.

Controls Palette

Chapter 2 BridgeVIEW Environment

The Controls palette consists of a graphical, floating palette that opens when you launch BridgeVIEW. You use this palette to place controls andindicators on the front panel of a VI. Each top-level icon contains subpalettes. If the Controls palette is not visible, you can open it by selecting Windows»Show Controls Palette from the front panel menu. You also can right-click, or pop up, on an open area in the front panel to access a temporary copy of the Controls palette. The Controls palette is available only when the front panel is the active window. The following illustration displays the top-level of the Controls palette.

Functions Palette

The Functions palette consists of a graphical, floating palette that opens automatically when you switch to the block diagram. You use this palette to place nodes (constants, indicators, VIs, and so on) on the block diagram of a VI. Each top-level icon contains subpalettes.

If the Functions palette is not visible, you can select Windows»Show Functions Palette from the block diagram menu to display it. You can alsopop up on an open area in the block diagram to access the Functions palette. The Functions palette is available only when the block diagram is the active window. The following illustration displays the top-level of the Functions palette.

Chapter 2 BridgeVIEW Environment

Controls and Indicators

Controls

orgraphs in traditional programming languages. BridgeVIEW contains avariety of controls and indicators that you can choose according to the kind of values or quantities you want to evaluate or display.

indicators

and

in G are similar to input and output parameters

You can configure all the controls and indicators using options from their pop-up menus. Popping up on individual components of controls and indicators displays menus for customizing those components. To access thepop-up menu, right-click on any object that has a pop-up menu.

The primary data types you use in BridgeVIEW applications

—

numeric,

Boolean, string, and tag, are described in the following sections.

Numeric

You use numeric controls to enter numeric quantities, while numeric indicators display numeric quantities. The two most commonly used numeric objects are the digital control and the digital indicator, shown below. You can find these controls and indicators in the subpalette of the

BridgeVIEW User Manual 2-6 © National Instruments Corporation

Controls

palette.

Numeric

Chapter 2 BridgeVIEW Environment

Label

Increment Buttons

Label

Digital Control

Digital Indicator

Boolean

You use Boolean controls and indicators for entering and displaying Boolean (TRUE/FALSE) values. Boolean objects simulate switches, buttons, and LEDs. The most commonly used Boolean objects are the vertical switch and the round LED, shown below, found in the Boolean subpalette.

String

You use string controls and indicators for entering and displaying ASCII characters. You can use strings for simple text messages displayed to the user and for character streams sent to serial devices, instruments, or files.

You can find the string control and indicator in Controls»String Table Tags. You can enter or change text inside a string control using the Operating tool or the Labeling tool. Enlarge string controls and indicators by dragging a corner with the Positioning tool.

If you want to minimize space that a front panel string control or indicator occupies, select Show»Scrollbar. If this option is dimmed, you must increase the vertical size of the window to make it available.

Chapter 2 BridgeVIEW Environment

Tag

You use tag controls and indicators for entering and displaying tag names or group names contained in the loaded tag configuration ( You can find tag controls and indicators in Controls»String Table Tags. For more information about the tag data type, see the section Tag Data

Type, in Chapter 4, Human Machine Interface.

Activity 2-1. Open and Run a VI

Your objective is to familiarize yourself with the basic concepts of virtual instruments. You will open, examine, and operate the front panel and block diagram of a VI.

1. Select File»Open, and open

.scf

) file.

Tank Simulation.vi

BridgeVIEW\Examples\G Examples\Apps\tankmntr.llb

The front panel appears as shown in the following illustration.

from the

BridgeVIEW User Manual 2-8 © National Instruments Corporation

Chapter 2 BridgeVIEW Environment

2. Run the VI by clicking on the Run button in the toolbar. The button

changes appearance to indicate that the VI is running.

3. Use the Operating tool to change the values of the Inflow Rates and

other controls. First, highlight the old value, either by double-clicking on the value you want to change, or by clicking and dragging across the value with the Labeling tool. When the initial value is highlighted, type a new value and press <Enter>. You also can click on the Enter button in the toolbar , or click the mouse in an open area of the windo w to enter the new value.

4. Stop the VI by clicking on the Stop button.

5. Open the block diagram of the Tank Simulator VI by choosing

Windows»Show Diagram.

The following illustration shows the block diagram.

6. Examine the different objects in the block diagram.

Every front panel in BridgeVIEW has an accompanying block diagram, which is the VI equivalent of a program. Think of the block

Chapter 2 BridgeVIEW Environment

diagram as source code. The components of the block diagram represent program nodes such as For Loops, Case structures, and multiplication functions. The components are wired togeth er to show the flow of data within the block diagram.

The outermost structure in this diagram is the While Loop. It continues to run until the power switch is turned off. The objects inside the loop include functions and subVIs that generate simulated data that is displayed on the historical trends and other objects on the front panel.

At this point, you do not need to understand all of the structures and objects completely. Chapters 9 through 16 of this manual describe in greater detail each element that appears in a VI.

7. Close the VI.

End of Activity 2-1.

BridgeVIEW Environment Project Menu

The BridgeVIEW system is comprised of the G programming language and a collection of software tools designed specifically for industrial automation applications. You can access these tools through the Project menu in your BridgeVIEW system. Table 2-1 provides a brief description of the items in the Project menu.

Table 2-1.

Project Menu Item Description

Configure BridgeVIEW Startup

Historical Trend Viewer Launches the Historical Trend Viewer (HTV). You can use the

BridgeVIEW User Manual 2-10 © National Instruments Corporation

BridgeVIEW Project Menu Items

Opens a utility you can use to configure BridgeVIEW to start particular VIs whenever you start BridgeVIEW.

HTV to view historical data logged in the Citadel Historical Database. For more information about the HTV, see Chapter 6,

Historical Data Logging and Extraction.

Chapter 2 BridgeVIEW Environment

Table 2-1.

BridgeVIEW Project Menu Items (Continued)

Project Menu Item Description

Launch Engine Launches the BridgeVIEW Engine. The BridgeVIEW Engine

manages the Real-Time Database, communicates with device servers, and performs alarm management and historical data logging. The BridgeVIEW Engine runs according to a configuration file called a file. You can create and edit

.scf

(SCADA Configuration File)

.scf

files using the Tag Configuration Editor. For more information about the BridgeVIEW Engine, see the section What Is the BridgeVIEW

Engine Manager? in this chapter.

Security»Access Levels

Opens a utility you can use to add, remove, and modify access levels in your BridgeVIEW system. If user accounts are defined in your system, you must have Administration privileges to edit the list of access levels. For more information about security and access levels, see Chapter 7, Advanced Application Topics.

Security»Change Password

Opens a dialog box to change the current user password. You must be logged in to change your password. For more information about security and passwords, see Chapter 7, Advanced Application

Topics.

Security»Edit User Accounts

Opens a utility you can use to create and edit user accounts in your BridgeVIEW system. If user accounts are defined in your system, you must have Administration privileges to create and edit user accounts. For more information about security and user accounts, see Chapter 7, Advanced Application Topics.

Security»Login

Opens a dialog box you can use to log in to the system. For more information about security, see Chapter 7, Advanced Application

Topics.

Security»Logout

Opens a dialog box you can use to log out of the system. For more information about security, see Chapter 7, Advanced Application

Topics.

Security»Privileges

Opens a utility you can use to view your access privileges. For more information about security and access levels, see Chapter 7,

Advanced Application Topics.

Server Tools»Server Browser

Launches the Server Browser. You can use the Server Browser to view information about the BridgeVIEW device serv ers. For more information about the Server Browser, see Chapter 8, Servers.

Chapter 2 BridgeVIEW Environment

Table 2-1.

BridgeVIEW Project Menu Items (Continued)

Project Menu Item Description

Tag»Browser

Launches the Tag Browser. You can use the Tag Browser to view information on all of the tags in the currently-loaded If the BridgeVIEW Engine is not running, you can use the Tag Browser to load a different

.scf

file. For more information about the Tag Browser, see the section What Is the Tag Browser? in this chapter.

Tag»Configuration

Launches the Tag Configuration Editor. You can use the Tag Configuration Editor to define all of the tags in your BridgeVIEW system. Also, you can configure other Engine parameters in the Tag Con figuration Editor. For more information about the Tag Configuration Editor, see Chapter 3, Tag Configuration.

Tag»Monitor

Launches the Tag Monitor. You can use the Tag Monitor to monitor the value, alarm state, and status of all tags in the system, as well as write the value to an output or input/output tag. The Tag Monitor launches the BridgeVIEW Engine if it is not already running. For more information on the Tag Monitor, see the What

Is the Tag Monitor? section in this chapter.

What Is the BridgeVIEW Engine Manager?

.scf

file.

When you run any G application that accesses the BridgeVIEW Real-Time Database, the BridgeVIEW Engine launches automatically, opening either the configuration (

.scf

) file you edited most recently or the one your

application selects programmatically. Launching the BridgeVIEW Engine brings up the Engine Manager

display, shown in Figure 2-1. The Engine Manager is a window into the BridgeVIEW Engine, through which you can control some of the behavior of the BridgeVIEW Engine.

Figure 2-1.

BridgeVIEW User Manual 2-12 © National Instruments Corporation

Engine Manager Display

Chapter 2 BridgeVIEW Environment

Table 2-2 provides a description of each of the fields in the Engine Manager dialog box. This table provides basic information about th e Engine Manager dialog box options. For a more complete understanding of how or why you might use the Engine Manager in a BridgeVIEW application, you must understand how to configure tags. See Chapter 3,

Tag Configuration.

Table 2-2.

Engine Manager Field Descriptions

Field Description

Engine Status Displays the current status of the BridgeVIEW Engine—whether launching,

running, or stopped.

Log Historical Data

Turns on or off logging of historical data to file. This button is pressed automatically if you selected Start logging on system start-up in your configuration file. If you do not have a valid event log path configured, or do not have a printer configured, this checkbox is disabled.

Log Events Turns on or off logging of alarms and events to file. This button is pressed

automatically if you selected Start event logging on system start-up in your configuration file. If you do not have a valid event log path configured, this checkbox is disabled.

Print Events Turns on or off printing of alarms and ev ents to your line printer. This button

is pressed automatically if you selected Start printing on system start-up in your configuration file. If you do not have a printer conf igured, this checkbox is disabled.

Run/Stop Engine Starts the BridgeVIEW Engine, or stops the BridgeVIEW Engine and shuts

down any loaded servers. Quit Engine Closes and exits the BridgeVIEW Engine process. Enable Error

Dialog

Enables or disables the showing of the Error dialog box. If this box is checked,

a System Error Display dialog box pops up for you to acknowledge the event

when a system error occurs. Server Browser Launches the Server Browser Utility. With this utility , you can see the servers

in your system, including OPC servers; view server information; and display

the server front panel if the server is running (VI-based servers only). Show/Hide

Shows or hides the System Event Display. System Event Display

Chapter 2 BridgeVIEW Environment

The Engine Manager shows the current state of the Engine, and has a System Event Display that shows the following:

• BridgeVIEW System Events

• When the Engine started and stopped

• Which servers have been launched

• Any System Errors that have occurred This information is written to the current BridgeVIEW System Log File,

found in the Engine Manager Display looks when the Show System Events Display button is enabled.

BridgeVIEW\Syslog

folder. Figure 2-2 shows how the

Figure 2-2.

Engine Manager with System Events Displayed

Once the BridgeVIEW Engine is launched and running, the Engine Manager is minimized and appears in your Windows taskbar. Click on the BridgeVIEW Engine icon in your taskbar to bring up the Engine Manager display.

Y ou can lea ve the BridgeVIEW Engine Manager display minimized unless you want to start or stop the Engine, or start or stop historical logging, event logging and printing, view system events, or view server information.

From the Engine Manager, you can reach the Serv er Browser utility, sho wn in Figure 2-4, by pressing the Server Browser… button. With this utility, you can see the servers in your system, view server information, and display the server front panel if the server is running (VI-based servers only).

BridgeVIEW User Manual 2-14 © National Instruments Corporation

Chapter 2 BridgeVIEW Environment

The Server Browser is shown in the following illustration. For more information about device servers, see Chapter8, Servers.

Figure 2-3.

The Show Server User Interface button appears on the Server Browserdialog box only when you invoke the Server Browser from theEngine Manager.

If your application does not shut down within a few seconds after you closethe BridgeVIEW Engine Manager, BridgeVIEW displays a dialog box notifying you to shut down your HMI application. You can ensure yourapplication shuts down when the Engine shuts down by monitoring the shutdown output of any Tags or Alarms VI or the Engine Status VI inyourdiagram. This technique is explained in Chapter4, Human

Machine Interface.

Server Browser

What Are System Errors and Events?

System errors are conditions on a system level (as opposed to a per tag

basis) that result in problematic functioning of the BridgeVIEW system. When a system error occurs, BridgeVIEW prompts the user with a dialog box. You can turn this dialog box on or off.

System events are changes in the system that cause a change in behavior

thatis not problematic. These include events reported by utilities such as the Tag Configuration Editor.

Chapter 2 BridgeVIEW Environment

Detailed system error and event messages are logged to a system log file. The messages are written to an ASCII file with a

SYSLOG

directory. BridgeVIEW automatically creates this directory, if

it does not exist already. The system log file names take the format,

YYMMDDHHMM.log

and

= minute.

What Is the Tag Browser?

With the Tag Browser utility, shown in Figure 2-4, you can view the general configuration of all configured tags in the system. Launch the Tag Browser by selecting Project»Tag»Browser.

A list of all the configured tags appears in the listbox. Select a tag by clicking on it, and the configuration for that tag displays on the right. For more detailed tag configuration information or to learn how to edit a tag configuration, see Chapter 3, Tag Configuration.

.log

extension in the

where YY = year, MM = month, DD = day, HH= hour,

Figure 2-4.

Tag Browser Utility

T able 2-4 describes each of the fields in the T ag Browser Utility dialog box.

BridgeVIEW User Manual 2-16 © National Instruments Corporation

Chapter 2 BridgeVIEW Environment

Table 2-3.

Tag Browser Field Descriptions

Field Description

Configuration File Displays the name of the configuration file you are browsing. Browse If the BridgeVIEW Engine is not running, press this button to select a

different configuration file.

Location Displays the full path of the directory containing the configuration file you

are browsing.

Engine Status Displays the current state of the BridgeVIEW Engine, whether it is loaded,

running or stopped.

Configured Tags Displays the list of all tags currently configured. Click on a tag to display the

tag configuratio n on the right. Edit Edits the selected tag in the Tag Configuration Editor. Name Displays the name of the currently selected tag. Use this display to select and

copy the tag name and paste it into your HMI diagram. Description Displays the description field for the currently selected tag. Type Displays the type of the currently selected tag: analog, discrete bit array, or

string. Access Displays the access rights for the currently selected tag: Memory, Input,

Output, or Input/Output. Group Displays the group to which the selected tag belongs. If this field is blank, the

tag does not belong to a group. Server Displays the name of the server connected to the currently selected tag.

If the tag is a memory tag, no server is associated with it. I/O Group Displays the name of the I/O group for the currently selected tag. If the tag is

a memory tag, no server or I/O group is associated with it. Item Displays the name of the item connected to the selected tag. If the tag is a

memory tag, no server, I/O group, or item is associated with it. Alarms Enabled Displays whether alarms are enabled for the selected tag. Auto Ack Displays whether alarms for the selected tag are acknowledged automatically . Full Scale Displays the full scale engineering value for the tag. This is displayed for

analog tags only.

Chapter 2 BridgeVIEW Environment

Table 2-3.

Field Description

Zero Scale Displays the zero scale engineering value for the tag. This is displayed for

analog tags only.

Units Displays the engineering unit for the tag. This is displayed for analog tags

only.

If the BridgeVIEW Engine is loaded, you can view the tags currently loaded with the T ag Bro wser. If the BridgeVIEW Engine is not loaded, the Tag Browser displays the currently loaded button to change the

The Tag Browser is a useful tool if you need to look at how a tag is configured while you are building your MMI VIs. You also can use the Tag Browser to change the loaded configuration file.

If you want to access the configuration information for a tag programmatically, you can use the VIs in the Tag Attributes palette. For more information about the Tag Attributes VIs, refer to Appendix A,

HMI Function Reference.

Tag Browser Field Descriptions (Continued)

.scf

file.

file. Use the Browse…

What Is the Tag Monitor?

With the Tag Monitor, you can monitor the value, unit, timestamp, alarm state, and status for selected tags in the system, as well as write the value to an output or input/output tag. You launch the Tag Monitor by selecting Project»Tag»Monitor. When you first launch the Tag Monitor, a tag selection dialog box displays all the tags configured in the currently selected tag configuration file. For more information about configuring tags, refer to Chapter 3, Tag Configuration.

Figure 2-5 shows the Tag Monitor.

BridgeVIEW User Manual 2-18 © National Instruments Corporation

Chapter 2 BridgeVIEW Environment

Note

Figure 2-5.

Tag Monitor Utility

Selecting the Tag Monitor from the Project menu automatically launches the BridgeVIEW Engine if it is not running already.

T ag information is shown in a table format, sorted b y tag name. When a tag has a non-zero tag status, the Status column indicates if the tag status is

Warning

Error

Table 2-4 describes the fields and captions in the Tag Monitor Utility.

Chapter 2 BridgeVIEW Environment

Table 2-4.

Tag Monitor Utility Field Descriptions

Field Descriptions

Tag Display Table Alphabetically lists the information for tags you have selected, including the

value, units, timestamp, status, alarm state and error, if any. For writable tags, which have a yellow background, clicking on the tag's value field brings up the Write to Tag dialog box, that lets you specify a new value for that tag. For bit array tags, the radix of the input value must be the same as that of the tag's value field in the Tag Display Table. Click OK to write the value in Value to Input and exit the dialog box. Click Apply to write the value in Value to Input and keep the dialog box open.

Trigger Tag Displays which tag, if any, you have selected to trigger refreshing of the Tag

Display Table. If you selected a tag to trigger refreshing of the Tag Display Table, the display refreshes when that tag changes value in the database, or the monitor timeout period is exceeded, whichever occurs first.

Monitor Timeout (sec)

Displays the time interval in seconds that the Tag Display Table is configured to refresh or update. If no trigger tag is selected, the display updates at this time interval. Otherwise, the Tag Display Table refreshes when the tag changes or the timeout interval is exceeded, whichever occurs first.

Status Details Brings up the Status Details dialog box, shown in Figure 2-6, that displays

a summary of the status for each tag in the system.

Select Tags to Monitor

Brings up the Select Tags to Monitor dialog box, shown in Figure 2-7, that lets you select which tags to monitor and configure how often to refresh the monitor display.

The Status Details dialog box, shown in Figure 2-6, displays a summary of the status for each tag in the system. Tags that have a warning are highlighted in blue, and tags in error are red. BridgeVIEW provides a description of the error or warning when possible. Internal codes are reported by BridgeVIEW; the Server Code is returned by the server of the tag. Clicking on Status Details is equivalent to selecting Tag Monitor»Status Details….

BridgeVIEW User Manual 2-20 © National Instruments Corporation

Chapter 2 BridgeVIEW Environment

Figure 2-6.

Status Details Dialog Box

With the Select Tags to Monitor dialog box, shown in Figure 2-7, you can select which tags to monitor and configure how often to refresh the monitor display. The Available T ags list box sho ws the tags not displayed in the Tag Display Table. By default, the timeout is set to 1.00 second. This controls how often the T ag Display Table is refreshed. By default, no tag is selected to trigger a refresh of the T ag Display Table. Y ou can select a tag to trigger a refresh of the T ag Display T able from the T rigger T ag Ring. Then, the Tag Display Table refreshes each time that tag is updated in the database, or when the timeout interval elapses, whichever occurs first. Clicking on Select Tags to Monitor is equal to selecting Tag Monitor»Select Tags….

Figure 2-7.

Select Tags to Monitor Dialog Box

Chapter 2 BridgeVIEW Environment

Select Tag Monitor»Preferences to bring up the Tag Monitor Preferences dialog box, shown in Figure 2-8, which lets you choose how

certain types of tags are displayed. You can control how the displayed precision for analog tags by modifying the Digits of Precision field. For bit array tags, the values can be in binary, octal, or hexadecimal format. The possible values for discrete tags can be 0 and 1 corresponding to Numeric Value; or a set of user-customizable strings, one equivalent to TRUE and the other to F ALSE. Check the Monitor Same Tags in Next Session check box to keep the same tag list for the next time you launch the Tag Monitor.

Figure 2-8.

BridgeVIEW User Manual 2-22 © National Instruments Corporation

Tag Monitor Preferences Dialog Box

How Do You Access Online Help?

Choose Help»Show Help. When you place one of the tools on a subVI node, the Help window shows the icon for the subVI with wires attached to each terminal. The following illustration shows an example of online help. This is the Acknowledge Alarm VI from the Functions»Alarms & Events subpalette.

Chapter 2 BridgeVIEW Environment

Simple/Complex Help View

In the Help window, you can specify whether you want to display the simple or complex view for block diagram objects.

Note

When you open the Help window, BridgeVIEW automatically defaults to the simple help view.

In simple help view, BridgeVIEW displays only the required and recommended inputs for VIs and functions. In complex help view, BridgeVIEW displays the required, recommended, and optional inputs for VIs and functions. It also displays the full path name of a VI. To access the simple help view, press the Simple/Complex Diagram Help switch or choose Help»Simple Help.

Chapter 2 BridgeVIEW Environment

In the Help window, requ ired inputs appear in bold text, recommended inputs appear in plain text, and optional inputs appear in gray text. When designing your own VIs, you can specify which inputs are required, recommended, or optional by popping up on an input or output on the connector pane and selecting the correct option from the This Connection Is submenu.

Links to Online Help Files

In the Help Window, you can click on the Online Help button to access BridgeVIEW online help as well as help files you have created using a help compiler. For more information on creating help files, see the section

Creating Your Own Help Files, in Chapter 5, Printing and Documenting VIs in G, in the G Programming Reference Manual.

BridgeVIEW User Manual 2-24 © National Instruments Corporation

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.

Chapter 3 Tag Configuration

General Attributes

General attributes include data type, maximum length for string and bit array tags, and the name, description, and tag group of the tag. The BridgeVIEW system supports four types of tags: analog, discrete, string, and bit array. These types differ by the inclusion of attributes within the operations, scaling, and alarm categories. The tag type is fixed when it is created. You must use the tag name to identify a particular tag. For information on how to configure the general attribute of a tag, see the

General section later in this chapter.

Connection Attributes

I/O connection attributes describe where the Engine sends or receives values for the tag and how to access that data. These tags have access rights of input, output or input/output. To configure the I/O connection attributes of a tag, refer to the Connection section later in this chapter.

Memory tags are not connected to a real world I/O point. Memory tags provide more complex monitoring, alarming, or control. For more information about memory tags, see the What Is a Memory Tag? section later in this chapter.

Operation Attributes

Operation attributes describe additional functionality that the Engine performs on a tag or its values. These operations include tasks such as setting initial values and enabling logging operations. To configure the operation attributes of a tag, refer to the Operations section later in this chapter.

Scaling Attributes

Scaling attributes describe what linear scaling function is applied to a tag's value. Scaling is useful for converting the range of values from measured units into a calculated range. Only analog (numeric) and Bit Array tags have Scaling attributes. To configure scaling attributes of a tag, see the

Scaling section later in this chapter.

BridgeVIEW User Manual 3-2 © National Instruments Corporation

Alarm Attributes

Alarm attributes describe abnormal process conditions for a given tag. Alarms are useful for notifying users of abnormal conditions. For example, if an analog tag measures the volume of a tank, a HI alarm can be used to indicate that the tank is full and an operator must perform some action and acknowledge this state before processing can proceed. For information on how to configure alarming attributes of a tag, see the Alarms section later in this chapter.

Static vs. Dynamic Attributes

Tag attributes are classified as either static or dynamic attributes. Static

attributes require you to restart the Engine when you change them from

the Tag Configuration Editor. A static attribute change is marked with a solid diamond in the Tag Configuration Editor. Examples of static attributes are general attributes and I/O connection attributes, such as server, device, or item.

Dynamic attributes do not require the Engine to restart. The Tag

Configuration Editor can change a dynamic tag attribute in a running Engine. A dynamic attribute change is marked with a hollow diamond in the Tag Configuration Editor. Examples of dynamic attributes include enabling logging operations, alarm attributes, and some scaling attributes. For more information about dynamic tag attributes, see the Tag Attributes

VIs section of Chapter 7, Advanced Application Topics.

Chapter 3 Tag Configuration

What Is the Tag Configuration Editor?

The Tag Configuration Editor is a tool that assists you in configuring all the parameters of the BridgeVIEW Engine. The chief component of this tool is the configuration of all tags in the system. Other configuration components include Alarm and Event Logging, and Historical Logging.

To start the Tag Configuration Editor, select Project»Tag» Configuration… from the menu bar of an open VI. Figure 3-1 shows the Tag Configuration Editor with

tanks.scf

loaded.

Chapter 3 Tag Configuration

Figure 3-1.

Tag Configuration Editor

The Tag Configuration Editor records all tag information and Engine parameters and stores this information in a BridgeVIEW Configuration File with the extension

.scf

(SCADA Configuration File). The BridgeVIEW Engine reads this file to determine all of the configuration parameters for execution. With the Tag Configuration Editor, you can specify the following:

• Tags used in the system

• File paths for historical data and event logging The

.scf

file does not contain any information about the VIs in your HMI. In fact, it is not specific to a single user application. Multiple user applications can run concurrently as long as they use the same set of tags. When you launch the Tag Configuration Editor, the last opened

.scf

opens automatically.

Note Only one .scf file can be loaded and running in the BridgeVIEW Engine

at a time.

If you edit a

.scf

file while the Engine is running and select Save or

Save As…, a dialog box confirms if you want to update the Engine

with your latest changes. If you want to update the Engine and any static attributes have been changed, the Engine shuts dow n and restarts. If you have changed only dynamic attributes in the

.scf

file, the Engine is

updated without restarting.

file

BridgeVIEW User Manual 3-4 © National Instruments Corporation

Chapter 3 Tag Configuration

Note Communication between the BridgeVIEW Engine and any device server is

stopped temporarily when the Engine shuts down and restarts.

How Do You Create a Tag?

From the main panel of the Tag Configuration Editor, press one of the following buttons: Create Analog Tag(s)…, Create Discrete Tag(s)…, Create String Tag(s)…, or Create Bit Array Tag(s)…. A separate window prompts you to define a new tag. The tag name must be unique within a given configuration ( when you finish creating the new tag, or Create New Tag to finish creating the new tag and create another tag of the same type. Any changes are not written to disk until you select Save from the File menu. For step by step instructions on using the Tag Configuration Editor to create a tag, see Activity 3-1, later in this chapter.

.scf

) file. Select OK on the pop-up window

How Do You Edit a Tag?

From the main panel of the Tag Configuration Editor, select one or more tags from the tags listed and press the Edit Tag(s)... button. A separate window displays the attributes for the tags you select, which you can then edit. When you finish editing a tag, select OK to save your changes and return to the main panel, Edit Next Tag to save your changes and go on to the next tag, or Cancel to discard your changes and return to the main panel. Selecting Cancel only cancels the changes made to the current tags. Any changes you make are not permanent until you save the configuration file.

You also can use a spreadsheet to edit multiple tags. Use File»Export… to export the tag information to a spreadsheet file, edit the fields, and then use File»Import… to import the tag configuration information from the edited spreadsheet file. For more information, see the section How Do You Use

Spreadsheet Files for Tag Configuration? in this chapter.

How Do You Delete a Tag?

To delete a tag from a configuration, select the tag(s) from the main panel of the Tag Configuration Editor and press the Delete Tag(s) button, and then save the SCF. Tags that will be deleted when you save the SCF are marked with a trashcan symbol. The Delete Tag(s) button also serves as an Undelete Tag(s) button if all selected tags have a trash can symbol. If you decide you want to keep one or more deleted tags, select those tags and press the Undelete Tag(s) button.

Chapter 3 Tag Configuration

Note If you delete a tag and save the .scf file, the tag and its configuration information

are removed from the

.scf file. You still can retrieve historical and event

information about the tag, but information such as the tag description, units, range, and alarm settings is lost.

What are Network Tags?

BridgeVIEW makes it easy to create distributed applications so more than one computer can be involved in an HMI application.

A BridgeVIEW server is a computer that allows tags configured in the current via a network. The server machine may or may not have an HMI running on it. In order for a machine to function as aBridgeVIEW server, the Engine must use an enabled.

A BridgeVIEW client is a computer that gets its data through tags from one or more BridgeVIEW servers. Tags remotely accessed from BridgeVIEW servers are network tags. An network tags from multiple BridgeVIEW servers. However, a BridgeVIEW client machine.

.scf

file to be accessed by other machines connected to the server

.scf

file that has the Allow Network Access option

.scf

file for a BridgeVIEW client can have

.scf

can import network tags from only one

.scf

file per server

A BridgeVIEW server can also act as a client and get its data from other BridgeVIEW server machines, as shown in the illustration below.

BridgeVIEW Servers

BridgeVIEW

Server/Client

BridgeVIEW Clients

Figure 3-2.

BridgeVIEW User Manual 3-6 © National Instruments Corporation

Flowchart of Server/Client Interaction

How Do You Add Network Tags?

On the BridgeVIEW server, all tags in an allowed by another BridgeVIEW system by opening the Tag Configuration Editor and selecting Configure»Allow Network Access. The tags are not shared until the

On the BridgeVIEW client, open the Tag Configuration Editor and select File»Import Network Tags…. The Select Tags for Network Import dialog box, shown in Figure 3-3, allows you to browse the network for an

.scf

wish to import, save the BridgeVIEW Engine.

.scf

file is saved on the server side.

file and select tags you wish to import. After selecting the tags you

Chapter 3 Tag Configuration

.scf

file can be viewed

.scf

file on the BridgeVIEW client and start the

Figure 3-3. Select Tags for Network Import Dialog Box

How Do You Set Default Values for Tag Configuration Fields?

You can simplify the tag configuration process by defining default values for several fields. These default values are then used when you create tags automatically, such as with the Configuration Wizard or by importing. For example, you might want to set the default to Log Data or Log Events, or set the log deadband to a particular value by default. You can set default values for tag parameters using the Set Default Parameters dialog box, shown below. To access this dialog box, select Configure»Default Parameters….

Chapter 3 Tag Configuration

The default values apply when creating a new tag, importing a tag from the server registry, or importing a tag from a spreadsheet. In the case of spreadsheet, a value in the spreadsheet ove rrides the default value for the field. For more information about the individual fields, see the How Do

You Configure Tags? section in this chapter.

How Do You Use Spreadsheet Files for Tag Configuration?

With the Tag Configuration Editor, you can export tag configuration information to spreadsheet files, and import tag configuration information from spreadsheet files. The files are tab-delimited text (

Select File»Export… to save the file as a tab-delimited you select Export…, a dialog box prompts you to select and order the fields you want in your spreadsheet file. If you intend to edit the spreadsheet file and then import the edited information back into the Tag Configuration Editor, select the All>> butto n to select all available fields.

BridgeVIEW User Manual 3-8 © National Instruments Corporation

.txt

) files.

file. When

Chapter 3 Tag Configuration

For easy viewing and editing in the spreadsheet, press the Use Default Order button.

After you edit the file, save it as a

.txt

file. Then, from the Tag

Configuration Editor, select File»Import… to import the information from the spreadsheet file.

If you use spreadsheet files with the Tag Configuration Editor, it is important that you understand the following points:

• If you do not choose all of the fields when exporting your data, you lose configuration information when you import it back to the Tag Configuration Editor.

• You might choose to export a subset of information, and then rely on tag default parameters when you import the data back in to the Configuration Editor. However, each row in the spreadsheet file must contain the tag name and data type fields, or the import mechanism cannot read it.

• Some configuration parameters, such as Historical Logging Configuration and Event Configuration, are inherited from the currently open

.scf

file when you import spreadsheet data.

• When importing, you can append the imported tags to the current

.scf

file.

Note If the tag name and data type fields are missing, the File»Import… option does

not work on the spreadsheet file.

Chapter 3 Tag Configuration

How Do You Configure Tags?

When you configure a tag with the Tag Configuration Editor, you define several attributes for the tag. You can separate these attributes into five categories: general, connection, operations, scaling, and alarms. Each of these categories is explained in detail later in this section.

If you import tag configuration information from a spreadsheet, follow thesame format in your spreadsheet as indicated in the Attribute column ofeach of the tables listed above. For more information about using spreadsheets, see the How Do You Use Spreadsheet Files for Tag

Configuration? section in this chapter.

Data Type

Configuration of a tag varies slightly depending on the data type. Thefollowing sections discuss the details of tag configuration for each datatype.

Analog Tags

An analog tag is a continuous value representation of a connection to areal-world I/O point or memory variable. This type of tag can vary continuously over a range of values within a signal range.

Use an analog tag when you want to express a continuous value (forexample, 0 to 100).

Discrete Tags

A discrete tag is a two-state (ON/OFF) value representation of a connection to a real-world I/O point or memory variable. This type of tagcan be either a 1(TRUE) or a 0(FALSE).

Use a discrete tag when you want to express a two-state (ON/OFF) value.

Bit Array Tags

A bit array tag is a multi-bit value representation of a connection to a real-world I/O point or memory variable. This type of tag can be comprised of up to 32 discrete values.

Use a bit array tag when you have a multi-bit value in which each of the bitsrepresents a flag or single value that is turned on or off. The maximum length of a bit array tag is 32.

BridgeVIEW User Manual 3-10 © National Instruments Corporation

General

Chapter 3 Tag Configuration

String Tags

A string tag is an ASCII character representation of a connection to a real-world I/O point or memory variable.

Use a string tag when you have binary information or an ASCII value. Forexample, you might use a string tag to obtain values from a bar code reader, or if you have data that does not fit into any other data type.

The general attributes of a tag include the name of the tag you are configuring, the group name to use for the tag, a description of the tag, andthe maximum length for string and bit array tags. Figure3-4 shows theGeneral tab of the Tag Configuration dialog box.

Figure 3-4.

Table3-1 provides descriptions of the general attributes of a tag. Fortagattribute information about the other configuration categories, seeTables3-2,3-4,3-5, and3-7.

General Attributes Dialog Box

Chapter 3 Tag Configuration

Table 3-1. General Configuration Attributes

Applies to

Attribute

Data Types

Description

Tag Name all Determines the name of the tag you are configuring. Always refer

to a tag by its name. Tag names are not case sensitive and can include any combination of printable characters (including space) with the exception of “/” (forward slash) and “\” (backslash).

Tag Group all Determines the group name to use for this tag. You can use

groups to assist in alarm management and reporting and to help organize tags in an application.

Tag

all Provides a description of the tag.

Description Maximum

Length

string, bit array

Determines the maximum number of bits in the bit array. The length is between 1 and 32 for bit array tags. String tags can be of any length.

Connection

You associate a tag with its real-world I/O point by assigning it a

I/O Group

, and

Item

in the

Connection

tab of the Tag Configuration dialog box, shown in Figure 3-5. If an I/O Group does not already exist for the server, you must create one before you can select or enter an item for the tag. The I/O Group is user-defined and provides you with a place to configure the rate and deadband for an item. For IAK and VI-based servers, you select the device as part of the I/O group configuration. For OPC servers, the I/O group conforms to an OPC group.

Server

When you edit a tag, use the ring inputs to assign values to the tag. Use the

Create…, Edit…

For more information about device servers, see Chapter 8,

, and

Delete

buttons to configure I/O Groups and Items.

Servers

Chapter 3 Tag Configuration

Figure 3-5.

Tag Connection Dialog Box

If a device server does not appear in the server name list, you must run the configuration or registration utility for your server before BridgeVIEW can access the server.

Table 3-2 provides descriptions of the connection attributes, and indicates the data types to which each attribute applies. For ta g attrib ute information about the other configuration categories, see Tables 3-1, 3-4, 3 -5, or 3-7.

Chapter 3 Tag Configuration

Table 3-2. Connection Configuration Attributes

Applies to

Attribute

Data Types

Description

Data Type all Determines the data type of the tag you are configuring.

BridgeVIEW tags can be analog, discrete, bit array, or string.

Tag Access all Determines the access rights for a tag. Tags can have access

rights of Memory, Input only, Output only, or Input/Output. Memory tags are not directly connected to real-world I/O points. You can use memory tags to monitor and control calculated values and enable historical trending and alarming on these values. Input only, Output only, and Input/Output tags are connected to real-world I/O points according to the Server, Device, and Item fields.

Server all Determines the device server that manages the communication of

the tag value. If the tag is a memory tag, this attribute is not used.

I/O Group all Determines the I/O Group to use for this tag. Select the I/O Group

this tag uses. The I/O Group is associated with the server . At least one I/O Group must be created for the server in order to configure a tag to use a server item. If the tag is a memory tag, this attribute is not used.

Item Name Filter

all Determines the string to filter the list of configured items. If the

tag is a memory tag, this attribute is not used.

Item all Determines the register, channel, or item on the device for this

tag. This might be a PLC register, a data acquisition channel, an OPC item ID, or a DDE item, depending on the server used for this tag. If the tag is a memory tag, this field is not used.

Access Path all Determines the access path for the selected server. If the tag is a

memory tag or if the server does not have access paths, this attribute is not used.

I/O Group Configuration

I/O Groups are used to configure item rate and deadband for items of a server and to select a specific device, if the server uses devices. For servers that support resource configuration, you also can use I/O groups to configure devices and communication resources. For OPC servers, an I/O group conforms to the concept of an OPC group, which is user-defined and controls timing. An I/O Group is associated with only one server and, if that

Chapter 3 Tag Configuration

server uses devices, with only one device. A server can have multiple I/O Groups associated with it.

I/O Group Configuration Options

The Create… button invokes the I/O Group Configuration dialog box, which you can use to specify group name and timing parameters. For servers that support resource configuration, you also can use this dialog box to select and configure devices and to configure communication resources.

The Edit… button invokes the I/O Group Configuration dialog box for the I/O Group selected in the I/O Group list. Use this dialog box to change the group name and timing parameters. For servers that support resource configuration, you also can use this dialog box to select and configure devices and to configure communication resources.

The Delete button invokes a confirmation dialog box. If confirmed, the I/O Group is deleted from the server configuration. Deleting an I/O Group does not delete the device and communication resource from the server configuration.

Figure 3-6.

I/O Group Configuration Dialog Box

Chapter 3 Tag Configuration

T able 3-3 provides descriptions of the operations that can be performed on an I/O Group. For information about other opeations that can be performed on an I/O Group, see Tab le 3-2.

Table 3-3.

I/O Group Configuration Attributes

Attribute

Description

I/O Group Name Determines the name of the I/O Group you are configuring. I/O Group

names are not case sensitive and can include any combination of printable characters (including spaces) with the exception of “/”

and “\”. I/O Group Description Provides a description for the I/O Group. I/O Group

Update Rate (secs)

Determines the rate for the server to update the item value in the

engine for all tags using the I/O Group. The server can have other

configuration options that determine the actual update rate. This is

the rate at which BridgeVIEW requests all tags configured with this

update rate be updated. I/O Group Deadband

(% of range)

Determines the deadband for the server to update the item value in the

engine for all tags configured with the I/O Group. Use 0% if you do

not want the server to apply deadbands to the item.

Not all servers support deadbands, and some

Note

might ignore this value.

Server Name Indicates the Server Name associated with the I/O Group you are

configuring. Communication Resource Provides a means to configure (create, edit, or delete) a

communication resource. This field is valid only for IAK servers. Device Determines a specif ic device used by the I/O Group and Serv er for this

tag. If the associated server is an OPC Server, this attribute is not used. Device Comm Resource Indicates the communication resource associated with the selected

device. This field is valid only for IAK servers.

Server Configuration Options

Use this group of fields to configure and select server resources. Some or all fields in this group might not be used depending on the server type. An IAK server has both Device and Communication Resource configuration capabilities.

Chapter 3 Tag Configuration

Communication Resource Configuration Options

For IAK servers, use the Create… button to invoke a new, untitled IAK Create Communication Resource Configuration dialog box. This configuration option is not used for other classes of servers.

For IAK servers, use the Edit… button to invoke the IAK Edit Communication Resource dialog box for the currently selected communication resource. This configuration option is not used for other classes of servers.

For IAK servers, use the Delete button to remove the selected communication resource from the server configuration. This configuration option is not used for other classes of servers.

Device Configuration Options Configuring Device Names

This option is available for servers that allow users to configure device names. OPC Servers do not use device names. For DDE Servers, the device name is used to specify the DDE application and topic. See the How

Do You Connect a Tag to a DDE Server? section in this chapter for more

information. The Add… button invokes the Device Entry dialog box, which you can

use to add a new device name for a selected server. If the server does not support device configuration, or if the selected device name is not valid, this button is disabled.

The Edit… bu tton inv okes the Device Entry dialog box, which you can use to edit an existing device name for a selected server. If the server does not support device configuration, or if the selected device name is not v alid, this button is disabled.

The Delete button invokes a confirmation dialog box. If confirmed, the selected device name is removed from the device list. If the serv er does not support device configuration, or if the selected device name is not valid, this button is disabled.

Device Configuration Options Configuring Device Resources

This option is supported by servers that allow users to configure device resources.

Use the Create… button to invoke a new, untitled Create Device Configuration dialog box. The options in this dialog box vary depending on the type of server. If the server does not support device configuration, this button is disabled.

Chapter 3 Tag Configuration

Use the Edit… button to inv ok e the Edit Device Configuration dialog box for the device currently selected in the device list. The options in this dialog box vary depending on the type of server. If the server does not support device configuration, this button is disabled.

Use the Delete button to remove the selected device from the server configuration. If the server does not support device configuration, this button is disabled.

Item Configuration

Use the Item Connection fields in the Connection tab (see Figure 3-5) to select and configure the item and access path (for certain OPC Servers only) for a tag.

Item Configuration OptionsConfiguring Item Names

This option is available for servers that allow users to configure item names.

The Add… button in vo kes the Item Entry dialog box, which you can use to add a new item for a selected server . If the server has access paths, you also can use this dialog box to add an access path. If the server does not support item configuration, this button is disabled.

The Edit… button invokes the Item Entry dialog box, which you can use to edit an existing item name for a selected server. If the server has access paths, you also can edit an access path. If the server does not support item configuration, or if the selected item is not valid, this button is disabled.

The Delete button invokes a confirmation dialog box. If confirmed, the selected item is removed from the item list. If the server has access paths, the selected access path is removed from the access path list. If the server does not support item configuration, or if the selected item is not valid, this button is disabled.

Item Configuration OptionsConfiguring Item Resources

This option is supported by servers that allow users to configure item resources.

The Create… b utton inv okes a server-dependent configuration dialog box, which you can use to configure a new item for a selected server . If the server does not support item configuration, this button is disabled.

Chapter 3 Tag Configuration

The Edit… button invo kes a server-dependent configuration dialog box, which you can use to edit the configuration of the selected item. If the server does not support item configuration, or if the selected item is not valid, this button is disabled.

The Delete button invokes a confirmation dialog box. If confirmed, the selected item is removed from the server configuration.

The Browse… button, which only applies to OPC Servers that support browsing, invokes the Browse OPC Server dialog box. Use this button to browse the list of available items and select an item and associated access path.

What Is a Memory Tag?

Memory tags are tags not connected directly to I/O points. They exist only

in the BridgeVIEW RTDB. To configure a memory tag, set the Access Rights of a tag to Memory.

When Should You Use a Memory Tag?

Use memory tags when you want to perform alarm calculations, or log historical data and event information on data that is either a software-generated value or a combination of values from different I/O tag readings. Below are some examples illustrating when to use memory tags.

Example 1When Not to Use a Memory Tag

You do not need to use a memory tag for program variables unless you want to use the historical and event logging or alarm management capabilities of the BridgeVIEW Engine.

An HMI displays the trend of a temperature tag and the difference between the current reading and a previous reading to allow operators to see the current rate of change in the temperature value. Although the individual values are logged for historical trends, the current difference is not.

You can configure the BridgeVIEW Engine to include the tag that reads temperature. The block diagram of the HMI reads the tag value and passes it to a real-time trend indicator. The dif ference between the current reading and the previous value is calculated in the diagram and passed to a front panel numeric indicator. The diagram retains the current temperature v alue and uses it after taking the next reading. Because the system does not need to perform any alarm management or historical logging based on the difference, no memory tag is used.

Chapter 3 Tag Configuration

Example 2When to Use a Memory Tag

A simple device server returns several items of data that, through a linear combination of values, represent a meaningful measurement in engineering units. The design of the device and its server software makes it difficult to combine these values within the server to make a single tag. The value of interest is not the individual points but the linear combination of these I/O points. The operators need historical trends and alarm management based on this single value.

In this situation, you can define a separate tag for each server item and a memory tag with engineering range and units of the final measurement. In the block diagram of the HMI VI, read individual tag values and calculate the linear combination of values in the diagram. Write the calculated value to the memory tag in the Real-Time Database and the BridgeVIEW Engine performs historical logging and alarm calculations according to the memory tag configuration.

Note

To learn more about how to build HMI VIs, refer to Chapter 4, Human Machine

Interface.

How Do You Automatically Generate Tags from Server Information?

Use the Configuration Wizard to create tags from the server information. The Configuration Wizard is useful if you want the BridgeVIEW Engine to monitor a large number of the I/O points in your system. To invoke the Configuration Wizard, press the Configuration Wizard button on the main screen of the Tag Configuration Editor or select Edit»Configuration Wizard…. For more information on servers, see Chapter 8, Servers.

When you run the server configuration utilities for the servers on your system, you can define devices and items for the I/O points the servers monitor and control. You can automatically create tags from these items with the Configuration Wizard. When the tags are created, the tag name, data type, I/O group, I/O connection, and scaling parameters are determined by the server information for each server item. The remaining tag parameters are determined by the default tag parameter settings. You can edit the default parameters by selecting opening the Tag Conf iguration Editor and selecting Configure»Default Parameters….

For IAK and VI-based servers, server information is read from the Common Configuration Database (CCDB). For OPC servers that support it, server information is read by browsing the server address space. When you generate tags, you can either add them to the existing configuration by

Chapter 3 Tag Configuration

selecting Append Tags to SCF? (default mode) or you can create a new configuration file.

How Do You Connect a Tag to an OPC Server?

You connect to an OPC server just like you connect to the National Instruments device servers from the Connection tab of the Tag Configuration dialog box. Any OPC servers installed on your machine are listed in the server name list. Select the OPC server you want to use. Create an I/O Group for the server, specifying the group deadband and update rate. Select or enter the Item name, which is the same as the OPC Server Item ID. You also can select or enter an access path for OPC servers if the server supports that.

How Do You Connect a Tag to a DDE Server?

Although no BridgeVIEW servers are based on Dynamic Data Exchange (DDE), you can connect a tag to any existing DDE Server. Select DDE Server as your server in the Connection tab of the Tag Configuration Editor to communicate with DDE servers. DDE Servers have an Application Name, Topic, and Item. In BridgeVIEW, the device in the I/O Group Configuration dialog box is set to (| = the “pipe” symbol) and the item in the Connection tab of the Tag Configuration dialog box is set to a tag to cell

R1C1

(item) of spreadsheet

item

sheet1

(application), set the tag fields to the following:

appname|topic

. For example, to connect

(topic) in Excel

Server: Device: Excel|sheet1 Item:

To specify a particular sheet ( (

Device:

DDE Server

R1C1

book1.xls

), set the device field to the following:

Excel|[book1.xls]sheet1

(in I/O Group Configuration dialog box)

sheet1

) within an open Excel file

(in I/O Group Configuration

dialog box)

How Do You Define a Group of Tags for Alarming?

While editing a tag, pull down the Tag Group Ring in the General tab of the Tag Configuration dialog box. You can select an existing tag group or define a new tag group by selecting Enter New…. To create, edit, or delete tag group definitions, select Tag Groups… from the Configure menu from the main Tag Configuration Editor panel.

Chapter 3 Tag Configuration

Operations

You can use tag groups to help define a subset of tags in the system. Tag groups are helpful when you want to examine the alarm states for a subset of tags in the system. See Chapter 5, Alarms and Events, for more information on alarm groups.

The operations attributes include when to update the tag value in the RTDB, whether to log data to a historical file, whether to log events associated with the tag, and information about the initial value of the tag at Engine startup. Figure 3-7 shows the Operations Tab of the Analog Tag Configuration dialog box. With this section of the dialog box, you can inform the BridgeVIEW Engine of what to do with the data in the RTDB.

Figure 3-7.

Tag Operations Dialog Box

Table 3-4 provides descriptions of the operations attributes, and indicates the data types to which each attribute applies. For ta g attrib ute information about the other configuration categories, see Tables 3-1, 3-2, 3 -5, and 3-7.

Chapter 3 Tag Configuration

Applies to

Attribute

Update

Data Types

all Determines when the Real-Time Database (RTDB) updates the

Deadband

Log Data analog,

discrete, bit array

Log Data Deadband

analog, discrete, bit array

Table 3-4.

Operations Configuration Attributes

Description

value for this tag. It is used to improve system performance and prevent unnecessary processing of tag values in the RTDB. The field is expressed differently for analog, discrete, string, and bit array tags. For analog tags, Update Deadband is a percent of full scale. The database updates analog tags only when a new tag value is different than the currently stored value by at least the Update Deadband. Use 0% if you want each ne w value for the tag to be saved in the RTDB. For discrete, string, and bit array ta gs, Update Deadband is expressed as either

Always

Determines whether a tag value is logged to historical files.

Determines when tag values are logged to disk. It is used to improve system performance and prevent unnecessary logging of data to disk. Like Update Deadband, the field is expressed differently for analog, discrete, and bit array tags. For analog tags, Update Deadband is a percent of full scale. The BridgeVIEW Engine writes new analog tag values to historical files only when a new tag value is different than the last logged value by at least the Log Data Deadband. Use 0% if you want each new value for the tag to be logged. For discrete and bit array tags, Update Deadband is expressed as either

On Change

Always

Log Resolution

analog Determines the resolution in engineering units for logging a tag

value in the Citadel Historical Database. T ag values are written to the database in a compressed format with the resolution specified by Log Resolution. Use

0.0

if you want the exact value written to the Citadel Historical Database. Notice that logging the exact value requires more time and disk space. The default value

0.1

Log/Print Events

all Determines whether events associa ted with the tag (for example,

changes in alarm state) are logged to event log f iles or printed to a line printer.

Chapter 3 Tag Configuration

Table 3-4.

Applies to

Attribute

Set Initial Value

Initial Value all The initial value used for this tag when Set Initial Value is ON.

Data Types

all Determines whether an initial value is used for this tag. If Set

Operations Configuration Attributes (Continued)

Description

Initial Value is OFF for this tag, the tag value is marked as uninitialized until its value is updated.

Ifthe tag is an Output only or Input/Output tag, the BridgeVIEW Engine sends the Initial Value to the server at Engine startup. Ifthe tag is an Input only or Memory tag, the Initial Value is stored in the RTDB at startup.

What Is Deadband?

In process instrumentation, deadband is the range through which an input signal can vary without initiating an observable change in output signal. Deadband usually is expressed in percent of full scale. Although the term deadband generally applies only to analog tags, other tag types have a limited type of deadband. A checkbox allows you to determine if updates to the RTDB and historical data files should occur with any new data from the device server or if the value has changed.

Note

The BridgeVIEW Engine performs historical logging and alarm management operations based on new values in the RTDB. If you set the Update Deadband too high, the RTDB might not be updated. This might result in inadequate historical logging or alarm management.

How Do You Use Deadband to IncreaseEngineThroughput?

The BridgeVIEW Engine uses Update Deadband and Log Deadband values to eliminate unnecessary processing on minor data value changes. Deadband allows you to define a significant change. The Engine ignores an operation if the change in data is not considered significant. Deadband is expressed as percent of full scale. For example, if the tag engineering range is 0 to 200 liters, a deadband of 5% is 10liters. In addition, through I/O group configuration, you can configure a server to apply a deadband to any items associated with that I/O group. Not all servers implement deadbands. OPC servers support deadbands.

Scaling

Chapter 3 Tag Configuration

How Do You Configure a Tag to Log Its Data or Events?

While editing a tag, click on the Log Data or Log/Print Events checkbox. If you want to log historical data or events, the BridgeVIEW Engine must have these processes enabled. To turn them on, open the Engine Manager and turn on the processes with the panel buttons, or configure the Engine to turn on these processes automatically at startup by selecting Configure» Historical… or Configure»Events… from the Tag Configuration Editor. You also can enable these parameters programmatically with System VIs that enable event or historical data logging.

How Do You Set Initial Tag Value at Startup?

While editing a tag, select the Set Initial Value checkbox. Then enter the initial value in the adjacent Initial Value field.

These attributes include what type of scaling to perform on a tag when communicating with the device server and the expected engineering range and units for the tag.

Table 3-5, provides descriptions of the scaling configuration attributes, and indicates the data types to which each attribute applies. For tag attribute information about the other configuration categories, see Tables 3-1, 3-2, 3-4, and 3-7.

Table 3-5.

Applies to

Attribute

Raw Full Scale

Raw Zero Scale

Eng Full Scale

Data Types

analog Determines the full scale (maximum) value used by the server

analog Determines the zero scale (minimum) value used by the server

analog Determines the full scale (maximum) value used by the

Scaling Configuration Attributes

for a tag.

BridgeVIEW Engine and the user application for a tag. Engineering Full Scale must be greater than Engineering Zero Scale.

Description

Chapter 3 Tag Configuration

Table 3-5.

Scaling Configuration Attributes (Continued)

Applies to

Attribute

Eng Zero Scale

Data Types

Description

analog Determines the zero scale (minimum) value used by the

BridgeVIEW Engine and the user application for a tag. Engineering Zero Scale must be less than Engineering Full Scale.

Units analog Determines the engineering units for a tag. Examples include

degrees Celsius, liters, and kilograms.

Scaling analog,

discrete, bit array

Determines the type of scaling algorithm to be used for a tag. The scaling methods differ according to tag data type. You can configure analog tags for linear or square root scaling, discrete tags for invert scaling, or bit array tags for mask scaling. All tags can be configured for no scaling.

Coerce analog Determines whether to coerce data so that it is valid for the target.

If scaling to output, the value must be within the raw (device server) range. If scaling to input, the value must be within the engineering (HMI) range.

Scaling Invert Mask

bit array Determines which bits are inverted for a bit array tag. Bits in

the mask that are The default mask is

are inverted; bits that are 0 are not inverted.

, indicating none of the bits are inve rted. In bit-wise logic terminology, the Engine performs an XOR with the Invert Mask to produce the scaled value.

Scaling Select Mask

bit array Determines which bits are used for the bit array tag. Bits in

the mask that are RTDB; bits that are

have their values passed through to the

are set to zero, regardless of the value received from the server. In bit-wise logic terminology, the Engine performs an AND with the Select Mask to produce the scaled value.

The next sections explain how to scale data. Often your application needs BridgeVIEW to manipulate the raw data used in the device server to put it in a form, called engineering units, suitable for the operators. The following sections describe the options for individual data types.

Note There is no scaling for string tags.

Chapter 3 Tag Configuration

Analog Tags

You can define the raw range and engineering range for a tag to perform simple conversions between the two ranges. The raw range, defined by Raw Full Scale and Raw Zero Scale, refers to the values used by the device server. Engineering range, defined by Engineering Full Scale and Engineering Zero Scale, refers to the values used by the BridgeVIEW Engine and HMI. Pull down the Scaling ring and select Linear to enable a linear (mx + b) conversion between raw and engineering ranges. Select Square Root to enable a square root conversion between the raw and engineering ranges. Figure 3-8 shows the Scaling tab of the Analog Tag Configuration dialog box.

Figure 3-8.

The following examples describe linear and square root scaling.

Analog Tag Scaling Dialog Box

ExampleLinear Scaling

A device server returns a simple voltage from 0 to 5 V. The voltage is related to a position sensor, and the real-world position is measured in centimeters, with 0 volts mapped to 50 cm and 5 V mapped to 100 cm.

Chapter 3 Tag Configuration

Configure the tag for raw range from zero (Raw Zero Scale) to five (Raw Full Scale). Select Linear, and set the engineering range from 50 (Eng Zero Scale) to 100 (Eng Full Scale).

ExampleSquare Root Scaling

A flow meter measures the flow rate of a liquid using a differential pressure reading. The device server provides 4–20 mA readings. The actual flow is measured in gallons per minutes (GPM). 4 mA corresponds to 0 GPM; 20 mA corresponds to 100 GPM.

Configure the tag for raw range from 4 (Raw Zero Scale) to 20 (Raw Full Scale). Select Square Root Scaling and set the engineering range from 0 (Eng Zero Scale) to 100 (Eng Full Scale).

How Do You Assign Units to an Analog Tag?

Use the Engineering Unit ring to assign units to a tag. If the desired unit is not in the list, select Enter New… and enter the desired unit. In the previous example, you select units of GPM.

Discrete Tags

The only scaling available for discrete tags is invert scaling. Click the Invert Data checkbox, shown in Figure 3-9 to advise the BridgeVIEW Engine to invert the discrete value when it communicates with the device server.

Chapter 3 Tag Configuration

Figure 3-9.

Scaling for Discrete Tag Configuration

Bit Array Tags

Bit array tags can have invert and/or select mask scaling. You can use the invert mask to determine which bits are inverted between the device server and the BridgeVIEW Engine. You can use the select mask to determine the bits you do not need. Figure 3-10 shows the Scaling tab of the Bit Array Tag Configuration dialog box, and Table 3-6 provides examples of tags configured for bit array scaling.

Chapter 3 Tag Configuration

Figure 3-10.

Table 3-6.

Bit Array Scaling Examples

Scaling for Bit Array Tag Configuration

Tag Name Length Raw Value Invert Mask Select Mask Scaled Value

Tag 1 8 0x0F 0x00 0xFF 0x0F Tag 2 8 0x0F 0x33 0xFF 0x3C Tag 3 8 0x0F 0x33 0x0F 0x0C Tag 4 8 0x0F 0x00 0x33 0x30 Tag 5 8 0x0F 0x33 0x33 0x30 Tag 6 16 0x0FF0 0x000F 0x00FF 0x00FF

Alarms

Chapter 3 Tag Configuration

These attributes include whether to enable alarms, under what circumstances a tag is in alarm, the priority level of an alarm, and how alarms are acknowledged. Each alarm limit has a priority, ranging between 1 and 15. In BridgeVIEW, 15 is the highest priority and 1 is the lowest.

There are two main types of alarms:

• Alarms based on status

• Alarms based on tag values Configuration for alarms based on tag values is specific to data type.

Therefore, many alarm attributes apply to only a subset of the BridgeVIEW tag data types. For more information about how to access alarm information, build alarm summary displays, and retrieve historical events files, see Chapter 5, Alarms and Events.

Table 3-7 provides descriptions of the alarm attributes, and indicates the data types to which each attribute applies. For tag attribute information about the other configuration categories, see Tables 3-1, 3-2, 3 -4, or 3-5.

Table 3-7. Alarms Configuration Attributes

Attribute

Alarms

Applies to

Data Types

all Determines whether alarms are enabled for a tag.

Description

Enabled Alarm

Deadband

analog Determines the amount an analog tag value must diverge from an

alarm limit before the alarm condition returns to normal. Alarm Deadband is expressed in percent of full scale.

Auto Ack all Determines how alarms can be ackno wledged. If set to Auto Ack,

the alarm is acknowledged automatically when the tag value returns to the Normal state. If set to User Must Ack, the alarm remains unacknowledged until the user acknowledges it, regardless of the alarm state.

Bad Status

all Determines whether to enable Bad Status alarms for the tag.

Enabled Bad Status

Priority HI_HI

all Determines the value (between 1 and 15) for the alarm priority

for the Bad Status alarm, where 15 represents the highest priority .

analog Determines whether to enable HI_HI alarms for a tag.

Enabled

Chapter 3 Tag Configuration

Attribute

Table 3-7.

Applies to

Data Types

Alarms Configuration Attributes (Continued)

Description

HI_HI Limit analog Determines the value, in engineering units, that invokes a

HI_HI alarm condition. The tag alarm state remains HI_HI until the tag value goes below the HI_HI alarm limit minus the alarm deadband.

HI_HI Priority

analog Determines the value (between 1 and 15) for the alarm priority

for the HI_HI alarm, where 15 represents the highest priority.

HI Enabled analog Determines whether to enable HI alarms for a tag. HI Limit analog Determines the value, in engineering units, that invokes a HI

alarm condition. The tag alarm state remains HI until the tag value goes below the HI alarm limit minus the alarm deadband.

HI Priority analog Determines the value (between 1 and 15) for the alarm priority

for the HI alarm, where 15 represents the highest priority.

LO Enabled analog Determines whether to enable LO alarms for the tag. LO Limit analog Determines the value, in engineering units, that invokes a LO

alarm condition. The tag alarm state remains LO until the tag value goes above the LO alarm limit plus the alarm deadband.

LO Priority analog Determines the value (between 1 and 15) for the alarm priority

for the LO alarm, where 15 represents the highest priority.

LO_LO

analog Determines whether to enable LO_LO alarms for a tag.

Enabled LO_LO Limit analog Determines the value, in engineering units, that invokes

a LO_LO alarm condition. The tag alarm state remains LO_LO until the tag value goes above the LO_LO alarm plus the alarm deadband.

LO_LO Priority

Discrete Enabled

analog Determines the value (between 1 and 15) for the alarm priority

for the LO alarm, where 15 represents the highest priority.

discrete, bit array

Determines whether to enable tag value alarms for discrete and bit array tags.

Chapter 3 Tag Configuration

Applies to

Attribute

Data Types

Alarm on discrete,

bit array

Discrete Priority

Alarm Invert

discrete, bit array

bit array Determines which bits are inverted before calculating the

Mask

Alarm Select

bit array Determines which bits are used for the bit array alarm

Mask

Table 3-7.

Alarms Configuration Attributes (Continued)

Description

Determines whether a discrete tag should be alarm on ON (high) or OFF (low). Determines whether a bit array goes into alarm if all of its bits are in alarm or if any of its bits are in alarm. This field is used only if both Alarms Enabled and Discrete Enabled fields are set to TRUE.

Determines the value (between 1 and 15) for the alarm priority for the tag value alarm, where 15 represents the highest priority.

alarm state. Bits in the mask that are an alarm when low (0). Bits that are

are inverted; thus cause

are not inverted; thus, cause an alarm when high (1). The default mask is 0, indicating none of the bits are inverted. In bit-wise logic terminology, the Engine performs an XOR with the Invert Mask to produce the alarm state. The Alarm Invert Mask is applied to the scaled v alue after any relevant scaling masks are applied.

calculation. Bits in the mask that are calculation; bits that are

do not cause an alarm, regardless of

are used in the alarm

their value. In bit-wise logic terminology , the Engine performs an AND with the Select Mask to produce the alarm state. The Alarm Select Mask is applied to the scaled value after any relevant scaling masks are applied.

Alarm Message

Tag Last

discrete, bit array

Determines the string used to provide additional information about the meaning of an alarm condition.

all Indicates when the last edit to a tag occurred.

Modified

Chapter 3 Tag Configuration

How Do You Configure Alarms for a Tag?

While editing a tag, click the Enable Alarms checkbox. Alarms are generated depending on the value or state of a tag. The alarms based on value vary with the tag data type. But for any tag, if the status is bad, a Bad Status alarm is generated. By default, Bad Status Alarm is enabled and has the highest priority (15). You can change this selection from the Alarms tab of the Tag Configuration Editor, shown in Figure 3-11.

Analog Tags

Analog tags have four alarm levels: HI_HI, HI, LO, and LO_LO. By providing separate alarm levels, you can provide more information about the nature of the alarm condition.

Figure 3-11. Alarms for Analog Tag Configuration

Alarms are calculated after scaling is performed. Alarm levels are expressed in engineering units.

Chapter 3 Tag Configuration

Discrete Tags

Discrete tags have one alarm state—either the tag is in alarm or it is not. You can determine whether a tag is in alarm when it is ON (High) or OFF (Low). Figure 3-12 shows the Alarms tab of the Discrete Tag Configuration dialog box.

Figure 3-12.

Alarms for Discrete Tag Configuration

Bit Array Tags

You can enable one of two types of alarms for bit array tags. Alarm on Any indicates the overall tag is in alarm if any of the bits are in alarm state. Alarm on All means the overall tag is in alarm only if all of the bits are in alarm state. You can use the Invert Mask to determine the bits that should use alarm on low (OFF) rather than the default alarm on high (ON). You can use the Select (AND) Mask to determine the bits that should be considered for the alarm. If you have bits in the Select Mask that are zero (OFF), these bits are not used in calculation of the tag alarm state. Figure 3-13 shows the Alarms tab of the Bit Array Tag Configuration dialog box.

Chapter 3 Tag Configuration

Figure 3-13.

Alarms for Bit Array Tag Configuration

String Tags

String tags have no alarm states based on tag value. They only support Bad Status alarms.

What Is Alarm Deadband on Analog Tags?

Alarm Deadband is a method commonly used to avoid repetitive alarm messages because of a tag value that hovers near the alarm limit. Alarm Deadband defines how much a tag value must change from the alarm limit before it is considered normal. For example, if a tag that represents a temperature value hovers near an alarm limit of 40 degrees Celsius, the tag might go in and out of alarm many times in a relatively short period of time. Table 3-8 shows examples of events with Alarm Deadband set to 0.0%.

Table 3-8.

Events with Alarm Deadband = 0.0%

Time Value Event Alarm Type

9:15:05 40.1 Yes HI 9:15:10 39.9 Yes Normal

Chapter 3 Tag Configuration

Table 3-8.

Time Value Event Alarm Type

9:15:15 40.1 Yes HI 9:15:20 38.5 Yes Normal

This type of situation clogs event files with redundant information and can cause operators some frustration in having to acknowledge alarms constantly when the tag has not changed significantly. You can use the Alarm Deadband to alleviate this problem.

For the tag to go into alarm, it must go above the exact Alarm Value (in the above example, 40). Howe ver , to be considered normal again, it must leave the Alarm Value by an amount greater than the Alarm Deadband. For example, if the range is 0 to 100 degrees Celsius, an Alarm Deadband of

1.0% (one degree Celsius) eliminates unnecessary events. Table 3-9 shows examples of events with Alarm Deadband set to 1.0%.

Time Value Event Alarm Type

9:15:05 40.1 Yes HI 9:15:10 39.9 No HI

Events with Alarm Deadband = 0.0% (Continued)

Table 3-9.

Events with Alarm Deadband = 1.0%

9:15:15 40.1 No HI 9:15:20 38.5 Yes Normal

How Do You Keep an Alarm Unacknowledged after the Alarm Returns to Normal?

While editing a tag, select the Alarm Acknowledgement Mode ring and choose either Auto Ack on Normal or User Must Ack.

Auto Ack on Normal

With this option enabled, when a tag returns to normal state, the alarm is automatically acknowledged. A message is logged to the event file if event logging is turned on for the tag. By default, Auto Ack On Normal is enabled.

Chapter 3 Tag Configuration

Activity 3-1. Configure a Tag, and View the

User Must Ack

With this option enabled, an alarm remains unacknowledged until the operator acknowledges the alarm.

Tag Configuration Parameters and Tag Values

The objective of this activity is to use the Tag Configuration Editor to configure tags for an HMI application and to become familiar with the Tag Browser and Tag Monitor utilities.

As with all servers, you must register the Tanks Server VI before you can use it. Most of the activities in this manual require the T anks Server VI, so you must run the Register T anks Serv er VI, as indicated in the steps belo w. For more information about registering servers, see Chapter 8, Servers.

1. Open the Register Tanks Server VI, which is located in the

BridgeVIEW\_servers\Tanks Server

2. Run the VI.

3. Close the VI.

4. Launch the Tag Configuration Editor by selecting Project»Tag» Configuration…. This launches the Ta g Configuration Editor.

5. Select the configuration file by selecting File»Open and choosing

mytanks.scf

loads following illustration.

from the

BridgeVIEW\Activity

into the T ag Configuration Editor, as sho wn in the

directory.

directory. This

Chapter 3 Tag Configuration

Note This configuration file uses data simulated by the Tanks Server. Y ou must ensure

that the

Project»Server Tools»Server Browser. If you do not see Registered Servers list, run the

BridgeVIEW\_servers\Tanks Server directory.

Tanks Server is registered with the BridgeVIEW Engine by selecting

Tanks Server in the

If any of the tags in the T ag Configuration Editor List have a prohibited symbol, shown at left, next to them, you have not registered the Tanks Server VI yet. You must register this server before you can use it. For information about how to register this server, see steps 1 through3inthis activity.

6. Create a tag called

Product

by selecting the Create Analog Tag(s)…

button.

7. Table 3-10 contains the settings you should choose when configuring

your new analog tag. Enter the values listed in the Setting column for each attribute in the Tag Configuration dialog box to configure the tag connection, operations, scaling, and alarms. For example, in the General tab of the Tag Configuration dialog box, you should type in

Product

as the tag name. After entering all of the values,

press the OK button to set the tag configuration.

Note You also can specify a tag name by selecting the proper I/O connections

(tag access, item, etc.) and then clicking on Paste Item Name to Tag Name. After doing so, the item name appears in the Tag Name field.

Chapter 3 Tag Configuration

Table 3-10.

Configuration Settings for Activity 3-1

Category Attribute Setting

General Tag Name

Tag Group Tag Description

Connection Tag Access

Server Name I/O Group Item

Operations Update Deadband

Product

group1

Volume of finished product in liters

Input Only

Tanks Server

ALL

tank2

1.00

(% of range) Set Initial Value Enabled,

0.00

Log/Print Events Enabled Log Data Enabled Log Deadband

5.00

(% of range) Log Resolution

0.10

(engineering units)

Scaling Engineering Unit

Scaling Raw Full Scale Raw Zero Scale

Liters

<none>

1000.00

0.00

Coerce to Range Disabled

Chapter 3 Tag Configuration

Table 3-10.

Configuration Settings for Activity 3-1 (Continued)

Category Attribute Setting

Alarms Enable Alarms Enabled

Alarm Acknowledge

Auto Ack on Normal

Mode Alarm Deadband

1.00

(% of range) HI_HI

Enabled,

950.00, Priority = 1

Enabled,

800.00, Priority = 1

Limit =

LO Disabled LO_LO Disabled

Priority = 1

8. Modify the

Bad Status Alarm

Mixer, Liquid

, and

Powder

Enabled,

tags, as specified in Table 3-11, to configure them for Historical Logging and Alarm Acknowledgement. T o edit a tag conf iguration, double-click the tag in the Tag Configuration Editor listbox or press the Edit Tag… button.

You can select multiple tags by holding the <Shift> key while dragging or clicking the mouse. When you edit multiple tags, the Tag Configuration dialog box shows three buttons: Edit Next Tag, OK, and Cancel. Select the Edit Next Tag to record any edits from the Tag Configuration dialog box and then display the next tag selected. Select OK to record any edits from the Tag Configuration dialog and return to the Tag Configuration Editor. Select Cancel to discard changes to the current tag and return to the Tag Configuration Editor.

Table 3-11.

Configuration Modifications for Activity 3-1

Category Attribute Setting

Operations Log Data Enabled

Log Deadband

0.00

(% of range) Log Resolution

0.10

Chapter 3 Tag Configuration

Table 3-11.

Configuration Modifications for Activity 3-1 (Continued)

Category Attribute Setting

Alarms Enable Alarms Enabled

Alarm Acknowledge

User must Ack

Mode

9. Save the configuration by selecting File»Save. The modified

file is provided for you in the

BridgeVIEW\Activity\Solutions

.scf

directory.

10. View the tag configuration using the Tag Browser. From a VI front

panel, choose Project»Tag»Browser… and select different tag names to see the configuration parameters. The Tag Browser is shown in the following illustration.

11. Close the Tag Browser.

12. Vie w the tag v alue and status of the Product tag with the Tag Monitor.

Select Project»Tag»Monitor…. Select Product and click on the Add>> button. Then select OK. The Select Tags to Monitor dialog box is shown in the following illustration.

National Instruments BridgeVIEW User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

BridgeVIEW User Manual

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Telephone Support (USA)

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National Instruments Corporate Headquarters

Important Information

Warranty

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WARNING REGARDING MEDICAL AND CLINICAL USE OF NATIONAL INSTRUMENTS PRODUCTS

Contents

Figures

Tables

About This Manual

Organization of This Manual

BridgeVIEW Concepts

G Tutorial

Appendices, Glossary, and Index

Conventions Used in This Manual

Related Documentation

Customer Communication

Welcome to BridgeVIEW

Required System Configuration

Installation

What Is BridgeVIEW?

How Does BridgeVIEW Work?

G Programming

Tag Configuration

Data Type

General

Connection

Scaling

Operations

Alarms

Events

Historical Data Logging and Extraction

Security

What Is the BridgeVIEW System Architecture?

User HMI Application

BridgeVIEW Engine

Device Servers

Where Should I Start?

What Is G?

How Does G Work?

Virtual Instruments

Front Panel

Block Diagram

Icon/Connector

Tools Palette

Controls Palette

Functions Palette

Controls and Indicators

Numeric

Boolean

String

BridgeVIEW Environment Project Menu

What Is the BridgeVIEW Engine Manager?

What Are System Errors and Events?

What Is the Tag Browser?

What Is the Tag Monitor?

How Do You Access Online Help?

Simple/Complex Help View

Links to Online Help Files

What Is a Tag?

Tag Attributes

General Attributes

Connection Attributes

Operation Attributes

Scaling Attributes

Alarm Attributes

Static vs. Dynamic Attributes

What Is the Tag Configuration Editor?

How Do You Create a Tag?

How Do You Edit a Tag?