Head downtime off at the pass

ControlDesign.com

Senior Tech Editor Rich Merritt reports on how industrial OEMs are marshalling the forces of smart sensors and diagnostics software to make sure trouble doesn't ride roughshod over machine utilization.

By Rich Merritt, Senior Technical Editor

MAXIMUM machine uptime is the ultimate objective of modern manufacturing. That’s why we cover topics such as simplified mechanicals, standardized controls, vibration analysis, and remote diagnostics. These are thoroughbred technology applications that industrial machine builders everywhere rely on to help improve their machines.

Diagnostic sensors and predictive software are a growing part of these approaches to increasing uptime. After all, it’s far better to fix problems when they’re small and easily serviced than it is to fix a machine in the field after it begins acting up or breaks, and then holds up a customer’s production line.

In fact, the field evidence of this strategy is finally out there. We found machine builders using built-in diagnostics, and also discovered that the necessary hardware and software is getting downright cheap. You may soon realize that you can’t afford not to build diagnostics into your machines.

Diagnostics at Work
FLSmidth, a builder of cement machinery in Bethlehem, Pa., had been plagued by users calling its support technicians for troubleshooting advice. These customers didn’t have staff capable of troubleshooting electrical and electronic problems, so FLSmidth’s technicians were spending two to four hours per call helping customers identify their problems.

As a result, the company partnered with Rockwell Automation to develop a new pneumatic transport system with more built-in diagnostic capabilities. The HMI terminal (See Figure 1 below) has diagnostic screens and alarms that describe exactly what’s wrong when a problem arises. Typical problems the system finds are motor-trip conditions, valve-coil failures, blown fuses, power-supply failures, and so on. Customers can fix most of these problems themselves.

	FIGURE 1: CEMENTING A CUSTOMER RELATIONSHIP
	Operators at this HMI terminal in a cement plant see diagnostic screens that point out problems. If they need help, an engineer from the machine builder can dial-in remotely and view diagnostic information to help with troubleshooting.

If a problem is more complex, however, engineers at FLSmidth can remotely access the system’s network, though they don’t have to do this very often. “The system works so well that we have minimal customer support calls,” says Larry Supon, electrical engineering and design group leader at FLSmidth. “But, when we do get a call, we can log on remotely, and immediately help our customer identify why the system faulted. This helps us deliver improved technical support, and means our customers can save hundreds or even thousands of dollars in the event of an electrical problem.”

Some devices can even troubleshoot themselves. Cummins, a builder of generator sets and transfer-switch controls in Columbus, Ind., employs controls that self-diagnose and diagnose problems remotely. “We check failure modes of engines, circuits on the engine, failure of certain control functions, excitation system failures, output power failure modes, output breaker failures and many more variables,” says Gary Olson, technical counsel at Cummins. “We sell about 20,000 systems a year with this capability. We’re about to start doing this on consumer products, which will make this number jump to more than 100,000 machines per year.”

Combining a modern fieldbus-type network with smart sensors makes it easier to implement these on-line diagnostics. Ron Newlun, controls manager for AEC, a plastics manufacturing equipment builder in Wood Dale, Ill., combines DeviceNet with smart I/O. “The intelligent network and I/O provide diagnostics that allow us to turn our HMI touchscreen into a genuine maintenance tool for our customers at no extra charge,” he says. “The I/O’s built-in diagnostics let maintenance personnel know what to bring to any given location, whether it’s a screwdriver or a replacement part. These diagnostics also help improve production scheduling, plan preventive maintenance of mechanical components, and a host of other things.”

Every Rose Has Its Thorns
As you might expect with a still-emerging technology, not everything is perfect in diagnostics land. “On some of our higher-end equipment, it works out fairly well,” reports Dan Stirpe, control engineer at Dauphin Graphic Machines, a builder of machinery for commercial printing and newspapers, located in Elizabethville, Pa. “In other cases, it was the equipment we added—to read the diagnostics and relay the information to operators—that caused the failure. We have far more failures in status reporting than we ever had in the devices themselves.”

Stirpe adds his company doesn’t access diagnostics over the Internet. “Most of our customers aren’t willing to risk unwanted access into their networks,” he explains. “We generally have a dedicated phone line run into our control consoles, and access via a remote-access server (RAS). Remote diagnostics work fine for some things, but often it’s not that useful. If you know there is a hardware failure and which piece of equipment on the system is causing the problem, then you can access it remotely, and determine why it’s not working. If the problem is communications or a high-level control issue, then it’s nearly impossible to diagnose remotely.”