Real Time for Maintenance Savings

July 29, 2009
Reduce Costs with CBM and OPC Real-Time Data
By Eric Murphy, columnist

Economies that rely on natural resources know all about boom and bust cycles. They know to “make hay while the sun shines” and when the times turn tough, they look for ways to optimize and save money. One way to do this is by using technology to optimize their plant maintenance practices and limited maintenance resources. An essential part of that process is to use real-time data to monitor equipment health, and inform condition-based monitoring (CBM) systems when something needs attention before failure occurs. OPC provides standardized access to all real-time data sources to feed the preventative maintenance systems with critical data.

Fix it before it fixes you

Computerized maintenance management systems (CMMS) and enterprise asset management (EAM) are essential components of any maintenance and reliability strategy. These applications must manage and optimize reliability and performance of plant physical assets and maintenance operations. As part of a company's overall asset management strategy, they are key to moving data from the plant floor up the organization to provide knowledge that helps a company make accurate decisions.

Reliable access to real-time data is required for good decision making. The goal of maintenance management systems is to improve maintenance performance by being the central organizational tool and to facilitate a shift from reactive to preventive maintenance. By acting on real-time data these applications allow maintenance professionals to set up automatic work order generation. Access to historical information also provides the systems with the means to adjust maintenance system setup over time to minimize unnecessary repairs and avoiding run-to-failure repairs.

Round it goes. When it stops? No one knows…

No one knows for sure when equipment is going to fail, but with access to the right data and by analyzing the results a condition-based monitoring (CBM) system can act on early indicators. With quality real-time data, a CBM system can monitor equipment accurately and alert maintenance professionals on any change in performance. Measurements that can be tracked include vibration, temperature, oil condition, motor characteristics, pump flows and pressure output. Capable CBM systems can monitor and analyze the measurements and schedule maintenance procedures when they are necessary, which maximizes equipment up-time. (Figure 1)

Figure 1 – OPC real time data feeds CBM systems

Real time in, real value out

Integration of condition-based maintenance equipment status and condition monitoring data with maintenance systems has been a challenge for many companies. The key is to integrate with computerized maintenance management software systems to automatically create work requests directly from real-time data and events occurring with plant assets. Today many industry leaders use OPC as their communication standard for collecting real-time data from control systems and equipment. Applications use OPC to acquire real-time data and to make the archived information available to external systems. Automating data collection eliminates slow and error-prone manual readings. Another benefit is on-demand access to the latest information exactly as it was stored in the automation system, including data quality and time stamps. This allows real-time condition-monitoring data to be fed directly into EAM systems for specified critical assets, enabling utilization-based (i.e. runtime hours) or condition-based (e.g. alarm condition) work orders to be triggered automatically when performance degrades beyond pre-defined thresholds.

Time to get real and get saving

A key aspect of maintenance planning is the availability of real-time data. EAM tools use the real-time information from equipment control systems to allow scheduling of maintenance tasks based on metered usage, not just a fixed date or time period. In addition, condition-based monitoring techniques give advanced warning of impending failure. This allows time for planning, ordering spares and taking advantage of any opportunities in the operating schedule. The early detection prevents potentially expensive consequential damage and downtime. Savings can also be made via reduced maintenance costs and saving labor and spare-parts costs by reducing unnecessary repairs and replacements.

Of course technologies alone cannot ensure the success of any CBM program; work processes must accommodate a CBM approach, and they must be championed by the maintenance team. This entails building CBM program awareness, adapting a maintenance strategy and philosophy, adopting new technologies and training.
However, the success of any CBM system depends on the timeliness and accuracy of collected data and the use of that data by the CMMS/EAM applications. OPC provides this critical data gathering component of condition-based monitoring systems and ultimately translates to cost savings.