We've heard a lot about predictive maintenace but in reality there have been few stories coming out of industry for us to verify this trend. In theory, today's "intelligent" instruments ought to supply plenty of information – not only about what is going on in the process but also what is going on in the instruments themselves. After all, predictive maintenance was touted as one of the major benefits of fieldbus, so by now we would expect to see some positive results from PM implementations.

One of the big difficulties is that predictive maintenance is such a powerful technique it gives manufacturers a competitive edge, and they are reluctant to talk about innovations that improve operating performance. Another problem is, it is quite a task to organize the enormous amounts of field data into a database that makes sense for the maintenance department.

We have managed to find one chemical plant in France that has adopted "100% predictive maintenance" over the past two years and the engineers are willing to talk about their success. It's not a large plant—300 field transmitters and 100 control valves in total —but you will find their experience useful. The article is on the web at www.controleng.com under CE Europe, June 2001, or click here.