Appeal to the broadest audience possible, says Kathy Carrizales, a supervisory-control-and-data-acquisition (SCADA) systems coordinator at Houston-based Devon Energy Corp. (www.devonenergy.com). “We have a real wide audience, from high-level management all the way down to engineers.”
Another reason for having the broadest possible main page is that users will be accessing the site using different levels of equipment, such as slow and fast computers or huge and small monitors, says Carrizales. Also, data will display differently on different systems. “Try and keep that in mind,” she emphasizes.
Her company, which is involved in oil-and-gas exploration and pipelines, uses Wonderware’s (www.wonderware.com) InTouch human-machine-interface (HMI) technology, as well as its Web portal, SuiteVoyager. With it, Devon has published between 75 and 100 pages, she says, that “show our pipelines, compressor stations and real-time data.” Carrizales adds that simpler, not fancy, is better for Web pages. Also, keep the number of fonts low and don’t crowd any page with too much information or graphics. Get feedback, she advocates, by asking, “Is the page easy to read?” And always have a way for users to navigate back to their starting point.
Feature KPIs
Include some key performance indicators (KPIs) on the main page, suggests North Andover, Mass.-based Haroon Rashid, who is responsible for Schneider Electric’s (www.schneiderelectric.com) SCADA and HMI systems and FactoryCast HMI and Web-based FactoryCast. Why? Because “you may want the viewer to visualize them right away, when they access the Web site.” He advises page developers to select the two or three most important KPIs.
From the main page, then, users can drill down into the site, but how deep? “The user can lose track of the data if there are too many layers or sub-layers,” Rashid points out. So he recommends a maximum of three layers. Roy Kok, HMI/SCADA manager for GE Fanuc Automation (www.gefanuc.com), in Foxboro, Mass., says, “You don’t want to drill through too many menus. You should be able to get to anything in three clicks.”
Keep colors to a minimum, Carrizales recommends. Also, “we try to use the same format and type of colors for inlets and outlets, just so it makes it easier for people to read.” Rashid also advises using appropriate color schemes because “when you’re in a process environment, you know that certain objects are regulated by color.”
Have visually comprehensible pages, he adds. That appeals to Carrizales. “I always think pictures and graphics help.” That means Devon may have an overview page showing all compressors and piping at a compressor station. “You can click on one of the compressors (objects) and go to the details of how it’s running. It may only go one or two levels,” she explains. But Devon also publishes some text-only pages, depending on “what we’re trying to deliver and to whom.”
Security is paramount, declares Bruce Fuller, business leader of automation software for GE Fanuc Automation, in Edmonton, Alberta, Canada. Colleague Kok agrees. “Get security and stay on top of it. Typically, the biometrics of the capture of an e-signature is done at the process. Verify that someone is allowed to make changes.”
Use common nomenclature to avoid confusion by users from various locations, advises Fuller. “How do you address being able to take the data and then represent it in either English or metric systems?” And because Web pages are communications tools, he emphasizes having unit conversion and language support.
Kenna Amos, [email protected], is an Automation World contributing editor.
