By Rich Merritt, Senior Technical Editor
AS WE REPORTED in this space last year, all the promised technology we’ve been expecting is not yet here. For the past few years, market researchers and industry prognosticators have been predicting that pressure and other sensors embodying advanced technology will dominate the market. They predicted that MEMS micro-machined technology, IEEE P1451.4 “smart sensors,” and fieldbus-compatible devices will soon be here.
Alas, like last year, we searched the product offerings (listed below), almost in vain. We found only one sensor with a fieldbus output, and three with HART outputs. Once again, not a single sensor has IEEE P1451.4 or uses MEMS in its construction. If they do, the vendors chose not to say so, which doesn’t make a bit of sense.
One new market study, Industrial Sensor Technologies and Markets, from Electronics Publications ($3,850, order from www.electronics.ca) continues the same fanciful prediction, saying that “strongest growth arises from the semiconductor industry and further integration of microelectromechanical systems, all of which are expected to grow at an average annual rate of 7.6%.”
That’s a very nice prediction, and in line with last year’s market studies. But one wonders: How are sales are going to grow that fast if nobody makes the sensors? Maybe all those fancy new sensors are appearing in automotive and semiconductor markets, but they certainly are not in the process control market.
We spotted two trends in this year’s offerings that the market researchers appear to have missed: Safety and stainless steel. We see two sensors addressing safety issues. We have sensors that conform to safety standards and practices, including NAMUR, SIL 2 and SIL 3, IEC Standard 61508/ISA S 84.01, IEC PED (Pressure Equipment Directive) category IV for mechanical integrity, and TÜV. Several other sensors are intrinsically safe, suitable for use in hazardous areas. We also found several sensors that use stainless steel in their construction, making them suitable for use in sanitary, abrasive and corrosive environments, and in clean-in-place applications.
Finding at least two sensors that are similar makes it a trend in our book, especially since that’s two more examples for a trend than all the market researchers have for their trends.
Product Roundup: Pressure Sensors
Pressure Transmitter has Fieldbus Output
The Barcon PPC pressure transmitter has a ceramic sensing face that resists corrosion and abrasive media, and can be ordered for sanitary applications with the 3A mark. It measures gases, vapors or liquids. Intrinsically safe models allow installation in explosive areas with certifications to CSA, FM and ATEX standards. Outputs include fieldbus protocols such as Profibus PA and HART. Pepperl+Fuchs; 330/486-0002; www.am.pepperl-fuchs.com
The Model 268 2600T Safety Pressure Transmitter complies with SIL 2 and SIL 3, is certified to IEC Standard 61508/ISA S 84.01, meets IEC PED (Pressure Equipment Directive) category IV compliance for mechanical integrity, and has TÜV certification for defining a process plant’s SIL. The instrument has self-diagnostics for safety applications, signal validation of both sensor and the electronics, and hardware/software redundancy. ABB; 215/674-6580; www.abb.com
Enhancements to the venerable LD301 smart pressure transmitter include improved turndown of 120:1 and NAMUR compatibility. It provides output current levels for failure and saturation conditions according to the NAMUR NE-43 specification, thus allowing for a standardized connection between 4–20 mA devices. Controllers based on the NAMUR specification can interpret the range saturation and sensor failure diagnostics and use it for interlocks in their control strategy. Smar; 713/849-2021; www.smar.com
Series 102M pressure sensors have been certified under ATEX and CSA as intrinsically safe for use in hazardous environments. The devices measure dynamic pressure events such as surges, pulsations, and spikes, making them suitable for monitoring the performance of compressors, pumps, and gas turbines, or to detect flow anomalies in piping systems. The sensors have a low-impedance signal that may be transmitted over long cable distances. PCB Piezotronics; 888/684-0011; www.pcb.com
The model 4500 sanitary pressure transmitter has 3-A and EHEDG approvals and provides a smooth, crevice-free housing design with high-quality electropolished wetted-surface finishes. It works in steam-in-place and clean-in-place applications, making it suitable for life-science applications. HART communications allows for increased diagnostic capabilities, faster calibrations and configuration changes. It works with the company’s AMS package for FDA compliance and audits. Emerson Rosemount; 800/999-9307; www.rosemount.com
Hazardous Pressure Transmitters
PT-L1 pressure transmitters are approved for use in hazardous locations. An intrinsically safe model is available for Class I, Div. I, Groups A, B, C and D, and an explosion-proof model is available for Class I, Div. I, Groups C and D; Class II, Groups E, F, G and Class III. Both have a solid-state transducer element with a DIN connection, 1/2-14 NPTM process connection and 4–20mA output. Scientific Technologies; 888/349-7098; www.stiapg.com