In addition to the planning framework we've covered thus far, there are some rules concerning graphic user interface (GUI) or operator interface development that it is important for you to review.
System Appearance
Keep the following appearance-related guidelines in mind as you develop your operator interfaces:
Do not crowd your pages with too many elements.
Use pop-up pages for controls wherever possible.
Accompany controls with indicators of the outgoing value where useful.
Standardize the appearance of the system in such a way that colors, fonts, and layout are consistent throughout the application.
Use no more than 3 fonts in any system.
Fonts should be easily readable.
The background color for pages should be kept neutral. Bright colors are often difficult to view for extended periods of time.
Status indicator colors are intended to inform operators as to the status or mode of a piece of equipment or equipment process; therefore the colors used for status indicators should be reserved only for that purpose.
In graphic-based systems, attempt to recreate the layout of the physical system as closely as possible so that operators are familiar with it.
Label all fields and equipment appropriately.
Align and space all fields and labels neatly.
Navigation
Navigation is an important aspect of any application you build. Keep the following navigation-related guidelines in mind when developing your applications:
Provide links to your windowed pop-up control pages and links to those pages showing complex arrangements of equipment.
Provide operators with the means to quickly navigate to frequently used pages.
Provide a categorized menu listing all application pages for easy navigation.
System Content
When designing the system content, be sure to remember to:
Design the application with the operators in mind, keeping ease of use as your goal. Remember that your application should make the system easier to use, not more difficult.
Keep the "look and feel" of the application consistent throughout the entire application. There should be a sense of continuity from page to page.
Design the application to guard against accidental operations however, do not make the system tedious to use.
Use standard naming procedures throughout the application, ensuring that equipment is accurately labeled.
Following these suggested guidelines will ultimately reduce application development time, increase operator productivity, and reduce training costs.