|Modern electronic differential-pressure systems are capable of eliminating many of the mechanical issues seen in traditional differential-pressure measurement. (Photo courtesy of Endress+Hauser)|
Technology has undoubtedly improved the capability of pressure measurement instruments in recent years, but the selection process has grown more complicated with more options to choose from.
As it is with any technology, the goal is to specify a solution that is both cost-effective and efficient for the application under consideration. “The current competitive and highly regulated industrial environment demands more efficiency, reliability, and safety than ever before,” says Inderpreet Shoker, analyst for ARC Advisory Group. “As a result, users now look for additional features in their pressure monitoring solutions, such as predictive diagnostics and software-based configuration.”
Pressure measurement technology has expanded to enable more access to process information through improvements in diagnostics, advanced monitoring in the health of the device, and monitoring of the process loop. According to Ehren Kiker and Chris Riordan, product managers for Endress+Hauser, Inc., some key enhancements in pressure measurement technology include improvements in sensor design—resulting in better response times, lower susceptibility to condensation, and support for more challenging applications—lower power consumption, and innovative platforms, such as electronic differential pressure.
“Careful consideration of specific requirements is crucial to choosing appropriate measurement technology,” says Shoker. “Some major considerations when selecting pressure measurement technology include pressure range, temperature range, ambient environmental conditions, overpressure protection, stability, accuracy, and communication protocol.”
Shoker says one major recent breakthrough for pressure measurement technology was the introduction of WirelessHART and the ISA100 series of standards. The emergence of WirelessHART and ISA100 offers end-users a reliable and user-friendly way to deploy wireless field devices, allowing what were once hard-to-reach and/or stranded assets to be connected to a plant asset management system.
This extended access to wireless technology gives users the opportunity to install field devices in measurement points that were previously not possible due to, for example, the high cost of wiring or hazardous areas. Encryption and mesh networking technologies have eased the concerns of end-users about security and wireless transmissions of process data, especially for monitoring applications, which has led to more users switching to wireless-enabled pressure transmitters.
“We continue to see advancements in the microprocessor technology,” says Shoker. “These advancements have facilitated development of more powerful and reliable pressure transmitters. Leading suppliers in the pressure transmitter market continue to leverage these ongoing technological developments to offer customers transmitters that are increasingly accurate, reliable, and functional.”
While modern pressure transmitters can be expensive than the more simplistic technologies that came before them, the capabilities they bring typically offset the added expense in the long run. For example, Shoker says multivariable transmitters can do what once required three devices to accomplish; measuring differential pressure, gauge pressure, and process temperature (in conjunction with an external RTD or thermocouple). Further, many multivariable transmitters can perform various flow calculations, as well as measure level in tanks. Shoker says it is this application versatility that is driving rapid increases in the popularity of multivariable transmitters.
Now that end-users have a wide variety of sensor technology options to choose from, the decision on which is the best and most efficient becomes more important.
“While it is good to have as many features as possible in your devices, it is not cost-effective to do so,” Shoker says. “Therefore, end-users should review their applications carefully and choose pressure measurement technologies with specific features that are crucial to their application.” For example, she says end-users who are monitoring pressure in hazardous locations or face certain space or wiring constraints will want to make sure they are placing these factors at the top of their priority list when specifying a device.
An advanced feature that is pushing the future of pressure transmitters is predictive diagnostic capability. “Predictive diagnostic tools are giving [end-users] greater flexibility for monitoring process conditions and allowing users to be more proactive in their maintenance activities rather than being purely reactive,” says Kiker & Riordan.
Looking into the future, Shoker expects advancements in sensor and microprocessor technologies will continue to improve the accuracy and reliability of pressure measurement devices. She also expects advances in wireless power transmission and energy harvesting technologies to increase the acceptance of wireless technology in industrial manufacturing operations.
“Although improving profitability remains a high priority for all companies, when faced with tight budgets, many tend to focus on short-term savings. Trying to lower the project cost in this situation, engineers tend to choose cheaper technology that may not offer benefits that help them save money in the long run,” says Shoker. “Therefore, it is important that users consider long-term cost of ownership and return-on-investment rather than just initial cost.”