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to Temperature Sensor Suppliers
About Temperature Sensors
sensors study includes the following types of temperature sensors and
Temperature Detectors (RTDs)
- Fiber Optic
Research completed the first edition of our temperature sensors study in
2000. A lot has changed in the temperature sensors market since that time.
A substantial amount of consolidation has taken place, involving
all the different types of sensors. The
following is a summary of some of the merger and acquisition changes that
have occurred in the temperature sensors business in the past seven years.
purchased US-based Alltemp Sensors, a manufacturer of thermocouples
and RTDs, in 1999. Wika
is based in Alberta, Canada. Wika
is now a dominant player in the temperature sensors market, especially
Engineering, a supplier of thermistors, was purchased by YSI, the
leading supplier of thermistors in 1999.
This transaction took place in 1999.
May 2000, Mikron Instruments purchased E2 Technologies, a manufacturer
of infrared thermometers. Mikron
subsequently changed its name to Mikron Infrared.
Instrument Corp. bought Atkins Technical in October 2001, and formed a
company called Cooper-Atkins.
Sensing purchased Thermometrics in November 2001, when it bought the
Sensing Solutions group of Spirent plc.
Thermometrics was previously the second-leading supplier of
thermistors to the Americas.
which is based in Everett, Washington, purchased Raytek, the leading
supplier of infrared thermometers. This occurred in September 2002. Raytek is located in Santa Cruz, California.
purchased Invensys’ Sensor System group in December 2002.
This included Fenwal, Elmwood, Clarostat, Sensym, Electro,
Hobbs, and NEI. Of these, Fenwal was a manufacturer of thermistors, and
Honeywell now has a significant place in that market.
January 1, 2005, Thermo Electric was sold to a private investment
company. This company
also owns Correge Sensors , which makes thermocouple wafers for the
semiconductor industry. Thermo
Electric is located in Saddle Brook, New Jersey and Brampton, Ontario,
Canada. Correge Sensors is in West Chester, Pennsylvania.
April 2006, Measurement Specialties acquired YSI Temperature, a
portion of YSI, and BetaTHERM, both manufacturers of thermistors.
May 2006, Engelhard was acquired by BASF.
BASF is a major chemical supplier based in Germany.
Engelhard is a manufacturer of fiber optic temperature sensors
located in Iselin, New Jersey.
transmitters take input from a temperature sensor and convert it into a
form that is suitable for transmitting a signal over a long distance. Most
temperature transmitters either convert the sensor signal to 4-20 mA or to
some type of digital signal. In the process of doing this, the signal is
conditioned and amplified so it can more easily be transmitted.
This is necessary because the voltage or resistance signal of most
temperature sensors is very small. It
is difficult to transmit this signal accurately over a distance due to
wire resistance and electromagnetic or radio frequency (RF) interference.
are five main types or temperature transmitters. These types are as
term ‘low-cost’ is obviously a relative term, and what is “low
cost” to one person might not be “low cost” to another.
The term ‘low cost’ also has a different meaning for
temperature transmitters than it does for other field devices such as
pressure transmitters. This
is because the prices of temperature transmitters are consistently lower
than the prices of pressure transmitters.
This is primarily due to the more complex and sophisticated sensors
required for pressure transmitters when compared to temperature
transmitters. Also, the cost
of the sensor is included in the price of a pressure transmitter, while
for temperature transmitters sensor cost is a separate item.
The prices of pressure transmitters range from under $200 to over
$1,000, while temperature transmitters are available for under $100.
A price of $250 might be considered “low cost” for a pressure
transmitter, but $250 is close to an average price for an analog
transmitters are very widely used, and they are used when a 4-20 mA signal
is desired. There is a very
large installed base of analog temperature transmitters in process and
other manufacturing plants. Because
end-users often replace like with like when ordering a replacement
product, analog transmitters still form a large portion of the temperature
primary characteristic of analog temperature transmitters is having a 4-20
mA output. Just as there is a
very large installed base of analog temperature transmitters in
manufacturing plants, so there is a very large installed base of
controllers and monitors that accept a 4-20 mA input.
This is changing over time as new plants are built and as more
companies buy more instrumentation. However,
“smart” never had the same impact on the temperature market that it
did in pressure or even flow, and many users are still buying analog
analog temperature transmitters can be programmed used a handheld device
or a personal computer. Values
that are typically programmed into a temperature transmitter are sensor
type (e.g., a thermocouple of a certain type or an RTD), span value, etc.
While smart temperature transmitters are programmable by
definition, there is a group of primarily analog transmitters that are
called “programmable.” These have the same features as analog transmitters, except
that they are programmable.
introduced the first smart pressure transmitter in 1983.
Since that time, “smart” devices have gained in popularity each
year. Even so, it took nearly
ten years for smart pressure transmitters to gain substantial market
share. Users are often very slow to adapt to new technologies, and
installed base has a major impact on decision making.
As noted above, smart temperature transmitters have never had the
same popularity as smart pressure transmitters.
primary characteristic of a smart temperature transmitter is having a
digital output. However,
“smart” refers to more than one characteristic.
To be smart, device must have the following three features:
of remote two-way communication
above are defining characteristics for any field device to be smart.
The following are additional characteristics that smart
transmitters typically have:
accuracy than analog transmitters
of accepting more than one type of sensor
addition to smart temperature transmitters, leading suppliers have also
introduced enhanced, high-performance temperature transmitters called
“high-tier” temperature transmitters.
While these transmitters are smart devices, they are more advanced
than most smart transmitters and are characterized by features that
enhance performance rather than their ability to communicate with other
devices. These features
include the following:
accuracy than smart temperature transmitter
of accepting more than one type of sensor
of high-tier temperature transmitters include Rosemount’s 3144 and 3244,
and Honeywell’s STT350.
efforts to create a universal fieldbus began in 1985, and they are
continuing today. A fieldbus
is a communication protocol that enables devices from different vendors to
operate together. A fieldbus
also makes it possible to send a number of signals from
field devices to the control room over the same pair of wires.
This drastically reduces wiring requirements because it is no
longer necessary to dedicate one pair of wires to each field device.
Finally, fieldbus makes it possible for field devices to talk to
each other directly, instead of communicating only via the control room.
two primary fieldbuses available today are Foundation Fieldbus and
Profibus P.A. (process automation). While many or the world’s competing suppliers, including
Rosemount, Honeywell, and Yokogawa, have rallied around the Fieldbus
Foundation protocol, hopes for a universally accepted fieldbus have been
dashed by continued support for Profibus P.A.
Support for Profibus P.A. comes from Siemens and companies that
develop Siemens products, and it is strongest in Europe. Profibus has not gained much of a foothold in North America.
However, Siemens’ strength in Europe means that these protocols
will continue to compete for the foreseeable future.
the adoption rate has been slow, end-users are now showing an acceptance
of Foundation Fieldbus and Profibus products.
Companies that are developing fieldbus products are typically
choosing to develop fieldbus pressure or flow products before they develop
fieldbus temperature transmitters. Users
who buy fieldbus products are currently doing so either for new plants or
on a pilot basis. However,
fieldbus will grow in temperature as more new plants are built and as more
new products become available.