by Jesse Yoder, Ph.D.

6 Key Trends in Temperature Technology

The process temperature measurement market continues to evolve as the user industries and technology change. When researching technology in the temperature segment, there are several key trends you should be aware. They are:
1. Many new temperature applications are moving from thermocouples to RTDs.
2. Within the RTD segment itself, thin-film devices are growing in popularity, while demand for wire-wound RTDs is falling.
3. Global competition is creating an environment for continued price erosion in temperature technology marketplace.
4. The temperature market is showing an increased use of transmitters versus direct wiring.
5. Likewise, there is increased use of transmitters versus temperature switches in safety applications.
6. Finally, integrated assemblies are becoming more widely available in the temperature technology segment.

Although temperature is among the simplest of the primary measurements used in industry today, being aware of the latest options available for temperature measurement can yield significant savings. Some best practices include:
• It is recommended to use thin-film RTDs for applications below 500 F.
• Use transmitters to reduce installation costs for long wiring runs and improve signal quality.
• Finally, use an integrated temperature assembly whenever possible to reduce purchasing costs.

“6 Key Trends in Temperature Technology” is based on a larger article on trends in temperature technology by Michael Cushing, Siemens Energy & Automation (www.sea.siemens.com). The full article will appear in an upcoming issue of Flow Control.

The temperature transmitter market is a stable one that fills an ever-present need, as temperature is arguably the most measured variable in industry. Because of the number of temperature measuring points in a process environment, there will always be a need for temperature transmitters to take a signal from a temperature sensor and convert it into a form that allows the signal to be transmitted accurately to the control room. Transmitters provide accurate and secure signal transmissions over distance. In many cases, transmitter cost compares favorably with that of lead wire. As such, the need for temperature transmitters in process and manufacturing environments is firmly established and not likely to change.

Despite the stable nature of the market, there is quite a lot of activity beneath the surface. Much of this activity has to do with the different types of temperature transmitters. The smart market has become divided between smart and high-tier devices. Leading the way in the high-tier temperature transmitters space are multivariable systems that accept two temperature sensor inputs. The adoption rate of Foundation Fieldbus and Profibus transmitters has been increasing as well. And much progress has also been made in the area of programmable temperature transmitters.

Programmable & Smart Transmitters
A shift is continuing among end-users away from analog temperature transmitters and towards programmable temperature transmitters. This shift has been going on for a number of years, and it is continuing. The change towards programmable transmitters is driven by several factors. One is that programmable transmitters offer more flexibility than analog instruments, and this flexibility is increasingly important as companies try to become more efficient and more competitive. Secondly, the shift to programmable transmitters allows end-users to move up one level without going all the way to smart or high-tier products. Both of these reasons are causing some end-users to replace analog temperature transmitters with programmable devices.

Another shift in the market is the transition to smart temperature transmitters. In 1999, almost 23 percent of temperature transmitter revenues in the Americas were from smart transmitters. By 2006, this number had increased to almost 38 percent. Many end-users are stepping up to HART from analog and programmable transmitters, and some are also adopting Foundation Fieldbus transmitters. Putting smart and high-tier transmitters together shows a clear trend towards smart instrumentation with more capabilities.

Transmitters vs. Sensors
It is interesting to compare the temperature transmitter market to the temperature sensor market, which provides a real study in contrasts:
• While the temperature sensor market is highly fragmented, with several hundred suppliers competing for market share, a single supplier dominates the temperature transmitter market.
• Many temperature sensors are available for under $100, while most temperature transmitters range in price from $200 to $700. This makes temperature sensors much more of a commodity item than temperature transmitters, although low-cost temperature transmitters are available.
• Temperature sensors can be used without temperature transmitters, if lead wire is provided, but temperature transmitters cannot function without input from a temperature sensor.
• The temperature sensor market is split almost evenly between the process and non-process industries, while the temperature transmitter market primarily services the process industries.
• The temperature sensors market is about four times as large as the temperature transmitter market, in terms of revenues.

The material for this article was abstracted from “The Market for Temperature Transmitters in the Americas, 2nd Edition” by Flow Research, Inc. (www.flowresearch.com).