Simplify Instrumentation Preventive Maintenance

By Jon Dietz, national field service manager, Endress+Hauser

Editor's Note: This article is adapted from a white paper, "Advanced tools simplify instrument maintenance." Download the full white paper to get additional information on how end users can use on-line diagnostics, asset management, proper scheduling of maintenance tasks, and automatic alerts to help simplify maintenance, lower costs, reduce parts inventories, and prevent unexpected equipment failures.

Thomas hasn’t been sleeping well lately. He oversees the 4,000 instruments that measure level, flow, temperature, pressure and other parameters at his chemical plant in Gendorf, Germany, but the control systems aren’t up to the task of analyzing all that data quickly to identify problems. So, the control system programmers are upset because they’re not getting maintenance orders in a timely manner. And management’s unhappy because they’re not getting real-time analysis to maximize uptime. Thomas has a huge challenge to solve. And he’s tired.

Thomas isn’t alone. In many process plants, maintenance of instrumentation falls into one of two categories. The first is “too little, too late,” where instrumentation fails due to a lack of preventive maintenance, often shutting down processes. The second category is “too much maintenance,” where companies remove, calibrate, clean and service instrumentation that doesn’t need it, at a high cost for parts, labor and equipment downtime.

Some instrument vendors now offer capabilities and services to help end users manage maintenance through online diagnostics, asset management, proper scheduling of maintenance tasks, and automatic alerts when problems come up.

Instrumentation Diagnoses Itself

Smart flowmeters and other process instruments have been available for years in “smart” versions, providing vital information for maintenance. For example, 4-20mA HART devices have been available since the 1980s. HART superimposes 35-40 digital parameters onto the 4-20mA signal, which can include device status, diagnostic alerts, configuration parameters, and so on. Fieldbus instruments provide much of the same information through various protocols such as EtherNet/IP and Profibus PA.

Unfortunately, more than 60% of instruments are used only to measure the primary process variable, with the status and diagnostic data ignored by the control system. Maintenance technicians often must access the data with handheld devices that plug into the flowmeter. A lack of understanding, training and useful software to process the data might account for maintenance departments not taking advantage of this capability.

Instrument suppliers recognized the problem and have gone to great lengths to equip flowmeters and other devices with on-board diagnostics, status information and other secondary device parameters that are needed by maintenance people — and they’ve provided the software needed to make all this data easily accessible and usable.

Instrument Maintenance Management

Modern instrumentation provides status and diagnostic information, but processing all of this data is often a problem. For example, at Thomas’ chemical plant in Germany, having its control systems read all the diagnostic information from all 4,000 devices, analyze it for problems, and issue instructions to the maintenance department would be a daunting problem for the plant’s control system programmers. It would also burden the control system with data not relevant to its primary task, which is real-time process control.

Instead, instrument manufacturers have developed software packages that perform all those functions. The packages fall into two basic categories: 1) instrument management programs, which analyze real-time information from instrumentation; and 2) asset management software, which keeps track of every instrument in the plant and stores vital data, such as manuals and parts lists.

Instrument management programs perform several functions to help maintenance departments, including:

• Configuration: helps maintenance configure new instrumentation during initial installation or when replacing an existing instrument.
• Condition monitoring: used to analyze real-time data coming from instrumentation, look for problems, and notify the maintenance department when a device needs attention prior to failure.
• Life-cycle management: tracks the entire life cycle of an instrument, from initial configuration to calibrations and repairs, and provides information for audits and safety regulations.

While a particular instrument manufacturer can provide information for its own instruments, what about all the other instruments in a plant from different manufacturers? Fortunately, standardization across the instrumentation industry makes that information available.

Endress+Hauser, a global provider of process measurement instrumentation, services and solutions, is a Strategic Alliance Partner in the Rockwell Automation PartnerNetwork^TM program. Together, Rockwell Automation and Endress+Hauser deliver integrated pre-engineered, pre-tested, supported, and maintained instrumentation and control and information solutions that provide plant-wide advanced diagnostics and process system life-cycle management.

^{The Journal From Rockwell Automation and Our PartnerNetwork™ is published by Putman Media, Inc.}