The main benefits that can be derived from wireless communication media include a reduction of wiring and installation of control systems in industrial process plants; improved speed at which these control systems can be engineered, configured and installed; and reduced ongoing maintenance costs. Remote communication savings are particularly attractive in greenfield installations to reduce the cost of new instrumentation wiring. They also can be used in revamps and modernization projects to reduce the cost of additional field instrumentation.
The installed cost of instrumentation can be quite high, and much of that cost is in the wiring back to the control system. The wiring cost, labor cost and cost of adding additional input/output (I/O) to the control system represents a significant commitment in the form of investment; therefore, plant personnel:
Tend to measure and collect the bare minimum set of process variables.
Tend to "overbuild" (in the form of bullet-proofing and "gold-plating") the devices in the field.
The secondary set of behaviors these investment drives spur is embodied in the ever-expanding set of parameters, values and algorithms embedded in smart field devices ," hundreds per transmitter in some cases. Because the investment is so high, plants struggle to do anything that can protect and deliver more value with that investment.
With the adoption and combination of micro-electro-mechanical systems (MEMS) and wireless technologies, a new paradigm is emerging. This new paradigm makes previous traditional field devices and field-centric control system approaches obsolete, and makes sensors and their installation, calibration and commission via wireless technologies relatively inexpensive. Low- cost wireless sensors and bus technologies are the harbinger of significant and real cost savings in plant construction, operation and maintenance.
Many significant hurdles and barriers still exist to the adoption of wireless field devices (one area of concern is robustness and safety), but many of these problems are being resolved. For example, at least one supplier provides a fail safe controller (FSC) that has, for several years, employed a fail safe safety network that is TUV approved for SIL3 safety applications using standard off-the-shelf communications technologies, including wireless communication.
Wireless delivers results
Process knowledge systems that employ wireless technologies in specific application areas innovatively can deliver improved results to chemical processing facilities today. Wireless technologies offer mobile productivity solutions. Together with remote, low-cost sensors, these technologies will deliver added value to the industry as the adoption rate improves and the technology becomes mature.
Hillman works for Honeywell's TPS systems business, new system development, and safety management systems. He is a TUV-Certified Functional Safety Expert (CFSE) and is manager, Asset and Abnormal Situation Management Marketing for Honeywell Industry Solutions, Phoenix. Contact him at Scott.Hillman@Honeywell.com.