The typical plant has a tremendous amount of instrumentation and control equipment. Much of it was installed or packaged with equipment skids, provided by the manufacturer/assembler. Many instruments have as their primary function the setup and performance of pre-operational or operational testing-lube oil skids, for example. Equipment suppliers often provide remote panels for pre-operational testing and operations. A typical plant's equipment, augmented by skid I&C, provides so much instrumentation that to tackle TBM of all of it would be a Herculean task!

Major process control loops feed a plant's DCS. This is done through drops, in modern plants. The typical DCS runs two redundant independent buses with self-checking diagnostics and the capability to swap buses, should a problem occur. Each has a fully redundant backup with the same capability. These robust systems haven't been the focus of a detailed RCM assessment by many clients, and I&C technicians and engineers, by and large, effectively maintain DCS controls. This suggests low value added benefit here at the typical plant installation. Risk management, maintaining redundancy, and "depth" have thus far been very effective. However, there are I&C opportunities.

The first is to select and identify candidates for NSM. I&C PMs include cals, channel checks (CCs), and functional tests (FTs). Self-diagnostic equipment can reduce or eliminate the need to perform FT. Self-calibration routines can eliminate the need to calibrate. Typically, a trouble alarm sounds if a plant DCS loses a drop or channel. Periodic checking of the channel alarm is all that's required.