Labview Style Guidelines

8/3/2019 Labview Style Guidelines

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Bloomy Controls

LabVIEW Style Guidelines

Peter Blume

President

[email protected]



www.bloomy.com© 2003 Bloomy Controls Inc.

Overview

General objectives

Examples without guidelines

Guidelines

Front panel

Icon/connector

Block diagram

Architecture Optimization

Clusters

Error handling

File organization

Documentation




General Objectives

Satisfy application requirements

Optimize:

Efficiency

Efficient = fast and memory-conserving

Readability

Readable = user-friendly and maintainable

Robustness Robust = reliable and bug-free




Front Panel Guidelines ² Text

General Minimize overall quantity of text

Controls Use succinct, intuitive labels

Indicate units in parentheses or use free labels

Enter descriptions or online help where further text is needed

Use transparent background

Top-level and dialog VIs Use large text size readily legible from several feet away

Maximize contrast between text color and background




Front Panel Text Example




Front Panel Layout

General Group related controls together

Consider decorations, tabs, clusters

Apply symmetry and spacing

Top-level and dialog VIs Size controls, indicators, and fonts according to importance

Use tab controls or subVIs to increase front-panel real estate

Apply color judiciously

Select three to four primary colors that go well together Avoid red and yellow in industrial applications, except where appropriate




Top-Level Panel Example




SubVI Panel Layout

Use default appearance for most objects and text Avoid using many colors, fonts

Consider default gray panel with 13-point application font

Use intuitive control positions Controls at left, indicators at right

Refnum/task IDs at top

Error clusters at bottom

Size panel adequately, but less than full screen

Keep things neat, intuitive, and symmetric




SubVI Example




Icon/Connector

Icon Intuitive text or graphic

10-point small fonts

Color-coding for icons of related subVIs

Connector pane Controls assigned to left terminals, indicators assigned to right

Refnum/task ID assigned to top left and right terminals

Error cluster assigned to bottom left and right terminals

Default values in parenthesis in owned label Priority used where appropriate

VI descriptions are required for ALL subVIs




Icon/Connector Examples

Nonconforming Conforming




Block Diagram

General

Leave the background color white

Set all control labels visible

Liberally document with free labels

Limit diagram to one 1024 x 768 screen

Avoid overlapping objects




Wiring Techniques

Apply

Left-to-right data flow

Straight wires

Align objects prior to wiring together Free labels to long wires

Consistent data types

Avoid

Overlapping or obstructed wires




Wiring Example




Diagram Ar chitectures

Modularize with subVIs

Top-level VIs should be composed of calls to subVIs

Do not over-modularize

Top level = state machine Define application as a series of states

Go to any state from any other state

Easy to modify, maintain, and debug

Self-documenting




Classic State Machine




State Machine Guidelines

Use enumerated or stringfor case selector

Poll user interface events in

³No Event, Default´ frame or in separate event structurein parallel loop

Use intuitive state names

Include ³Initialize´ and ³Shutdown´ states




Enumerated State Machine




Nonconforming Example




Conforming Example




Event-Driven State Machine

Consider desired response to GUI for determining

state granularity

Consider applicability of queues




Optimizing Diagrams

Use Wait in all While Loops

Avoid

Local and global variables

Sequence structures

Unnecessary nesting

Coercions

Unnecessary operations

in looping structures Easy I/O VIs

Inefficient I/O




Optimizing Diagrams ² Efficient I/O




Clusters

Group related data into clusters

Follow front-panel text guidelines

Consider saving as strict type definition

Avoid nesting clusters and arrays beyond

two levels

Always use bundle and unbundle by name




Cluster Example ² Nonconforming




Cluster Examples ² Conforming




Error Handling

All VIs must trap and report any I/O-related errors

that might occur

Trapping is facilitated by propagation of error cluster

I/O functions include DAQ, file I/O, instrument I/O,communication

Reporting methods include dialog prompt or log to file




Error Handling ² Nonconforming




Error Handling ² Conforming




File Organization

Subfolder hierarchy required

Organize project into subfolders

Recommended subfolder

hierarchy:




Documentation

Use guidelines to document VIs

Use LabVIEW custom printing options to create a

function reference manual

Include specification and/or basic operating

instructions to complete documentation




Conclusion

Using LabVIEW style guidelines ensures:

Multiple end users will find software robust and

user-friendly

Multiple developers will find software readable andmaintainable




About Bloomy Controls

Test, measurement, automation, and control specialistssince 1991

Systems integration, software development, andtraining provider

NI Select Integrator and Certified Training Center 3 Certified LabVIEW Architects

8 Certified LabVIEW Developers

1 Certified TestStand Architect

2 Certified TestS

tand Developers 8 Certified Professional Instructors

Offices in Windsor, CT; Milford, MA; and Mahwah, NJ




Contact Bloomy Controls

Email [email protected]

Write or visit

CT, Western MA,

Eastern NY:

Eastern MA, RI,

Northern New England:

Greater NYC,

NJ:

839 Marshall Phelps Rd. 100 Medway Rd., Ste 202

Windsor, CT 06095 Milford, MA 01757 Mahwah, NJ

(860) 298-9925 (508) 902-0054 (201) 818-0117

Labview Style Guidelines

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