Mts Sensors Faq Md 7815 v2
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A D V E R T I S E M E N T THE HIGH TEMPERATURES seen in industrial processes like steel production, oil and gas drilling, power generation, injection molding, and thermoforming as well as in the aerospace and transportation in- dustries can be especially hard on sen- sors. Here’s how to help your sensors survive temperature-related challenges. Q: How do extended temperatures affect sensors? A: Many types of sensors experience a loss of accuracy called sensor drift at temperatures outside their rated range. Software algorithms that take tempera- ture into account may be able to com- pensate for this drift. In fact, most dig- ital sensors have such algorithms built into their signal processors. Another, costlier, effect of extreme temperatures is the shortening of sen- sor life. Sensors’ semiconductor com- ponents carry a mean-time-to-failure (MTTF) rating usually determined at a 25°C ambient temperature. In practice, however, MTTF is halved for each 10°C the semiconductors see over that ambi- ent temperature. So, if your sensor’s signal processor has a stated MTTF of 10 years at 25°C, but your process has them seeing 45°C, be prepared to replace that processor every 30 months. When planning for MTTF, don’t forget that temperatures inside electronics housings can be significantly higher than ambient temperatures. Q: How can I protect my sensors from extended temperatures? A: Cooling your electronics enclosures to protect sensitive parts is one way to keep your sensors working accurately. But cooled enclosures add complexity and are not feasible in many environments. Another option is to locate the sensi- tive electronics away from the extreme temperatures. Sensing modules take the heat and send their signals by wire to processors located in cooler spots. Q: Do some sensors work in extended temperatures? A: It is possible to source semiconduc- tor components that are rated for high- er temperatures. Some, for instance, state their MTTF at 85°C. However, sourcing high-temperature semiconduc- tors can significantly increase the cost of the sensing system. In fact, many sensing mechanisms are less sensitive to extended temperatures than their signal processors. Sensor technology dictates whether a sensor functions reliably in difficult environ- ments. Sensors that directly convert physical measurement to electrical signals, like electromechanical sensors, potentiometers, and optical sensors, experience greater sensor drift at high temperatures. Sensors that rely on direct contact must also account for thermal expansion at extreme temperatures. Magnetostrictive position sensors, on the other hand, use a non-contact method to convert the physical quantity being measured to a mechanical strain at the sensing point, so these sensors are less sensitive to temperature. Q: How do magnetostrictive sensors work? A: Magnetostriction is the phenome- non that causes ferromagnetic materi- als like iron, nickel, and cobalt, to mi- croscopically distort in response to a magnetic field. These elastic strains are directly proportional to the strength of the magnetic field. Magnetostrictive position sensors make use of this with a ferromag- netic waveguide and a mobile magnet secured to the item whose position is being measured. The waveguide carries a short current pulse along its length which generates a radial magnetic field. When the pulse approaches the mobile magnet, the interaction of the radial Sponsored by MTS Sensors Linear Position Sensors for Extended Temperatures magnetic field with that of the mobile magnet causes a magnetostrictive response in the waveguide. The magnetostrictive response takes the form of an ultrasonic torsion strain wave that travels back down the wave- guide at a constant speed. At the waveguide’s end, a strain converter transforms the strain wave into an electrical signal. Electronics correlate the wave’s travel time with the position of the moving magnet. Q: What are the advantages of magnetostrictive sensors? A: Magnetostrictive position sensors provide absolute position readings, not relative values that require recalibration. This can be a big advantage in high- throughput or extreme environments. Designers can also take advantage of the ability of magnetostrictive sensors to return the positions of multiple items simultaneously. Because the current pulse is not changed when magnetic fields interact, it can continue along the waveguide to interact with the magnetic fields of additional mobile magnets. A sensor reading multiple inputs can install more compactly and save money by only requiring a single set of signal-processing electronics. Magnetostrictive position sensors also last longer than other sensor technolo- gies because they are non-contact and have no moving parts or parts in contact that can wear and require replacement and recalibration. Because there is no contact, there are no delicate sensing surfaces to clean or sensitivity to dirt or dust. And the use of a torsional strain wave makes the sensors less sensitive to shock and vibration. Q: What are my options for extended temperature magnetostrictive sensors? A: Some magnetostriction position sen- sors are rated for extended tempera- tures. For instance, MTS Sensors’ Tem- posonics ET works up to 105°C. It can be supplied with an ATEX rating for ex- plosive environments and with a 316L Stainless housing if required. Other extended temperature options include MTS Sensors’ RD4 and RT4, which are good up to 100°C. Both models allow for remote location of the electronics which connect to the sensing module via a wire and pipe. FREQUENTLY ASKED QUESTIONS Temposonics ® MTS Systems Corporation, Sensors Division 3001 Sheldon Drive Cary, NC Tel. 800-633-7609 www.mtssensors.com [email protected] Delivering exceptional reliability and repeatability in extended temperature conditions Click to learn more Model RD4 Model RT4 Model ET Magnetostrictive Linear Position Sensors Magnetostrictive position sensors rely on the fact that ferromagnetic materials respond to magnetic fields with elastic microscopic strain. The interaction of two magnetic fields sends a strain wave down the waveguide to convert into an electrical signal. Electronics correlate travel time with the absolute position of field interaction. How it works: Magnetostrictive position sensors
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High temperature sensors
Transcript of Mts Sensors Faq Md 7815 v2
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A D V E R T I S E M E N T
THE HIGH TEMPERATURES seen in industrial processes like steel production, oil and gas drilling, power generation, injection molding, and thermoforming as well as in the aerospace and transportation in-dustries can be especially hard on sen-sors. Heres how to help your sensors survive temperature-related challenges.
Q: How do extended temperatures affect sensors?A: Many types of sensors experience a loss of accuracy called sensor drift at temperatures outside their rated range. Software algorithms that take tempera-ture into account may be able to com-pensate for this drift. In fact, most dig-ital sensors have such algorithms built into their signal processors.
Another, costlier, effect of extreme temperatures is the shortening of sen-sor life. Sensors semiconductor com-ponents carry a mean-time-to-failure (MTTF) rating usually determined at a 25C ambient temperature. In practice, however, MTTF is halved for each 10C the semiconductors see over that ambi-ent temperature.
So, if your sensors signal processor has a stated MTTF of 10 years at 25C, but your process has them seeing 45C, be prepared to replace that processor every 30 months. When planning for MTTF, dont forget that temperatures inside electronics housings can be significantly higher than ambient temperatures.
Q: How can I protect my sensors from extended temperatures?A: Cooling your electronics enclosures to protect sensitive parts is one way to keep your sensors working accurately. But cooled enclosures add complexity and are not feasible in many environments.
Another option is to locate the sensi-
tive electronics away from the extreme temperatures. Sensing modules take the heat and send their signals by wire to processors located in cooler spots.
Q: Do some sensors work in extended temperatures?A: It is possible to source semiconduc-tor components that are rated for high-er temperatures. Some, for instance, state their MTTF at 85C. However, sourcing high-temperature semiconduc-tors can significantly increase the cost of the sensing system.
In fact, many sensing mechanisms are less sensitive to extended temperatures than their signal processors. Sensor technology dictates whether a sensor functions reliably in difficult environ-ments. Sensors that directly convert physical measurement to electrical signals, like electromechanical sensors, potentiometers, and optical sensors, experience greater sensor drift at high temperatures. Sensors that rely on direct contact must also account for thermal
expansion at extreme temperatures.Magnetostrictive position sensors, on
the other hand, use a non-contact method to convert the physical quantity being measured to a mechanical strain at the sensing point, so these sensors are less sensitive to temperature.
Q: How do magnetostrictive sensors work?A: Magnetostriction is the phenome-non that causes ferromagnetic materi-als like iron, nickel, and cobalt, to mi-croscopically distort in response to a magnetic field. These elastic strains are directly proportional to the strength of the magnetic field.
Magnetostrictive position sensors make use of this with a ferromag-netic waveguide and a mobile magnet secured to the item whose position is being measured. The waveguide carries a short current pulse along its length which generates a radial magnetic field. When the pulse approaches the mobile magnet, the interaction of the radial
Sponsored by MTS Sensors
Linear Position Sensors for Extended Temperatures
magnetic field with that of the mobile magnet causes a magnetostrictive response in the waveguide.
The magnetostrictive response takes the form of an ultrasonic torsion strain wave that travels back down the wave-guide at a constant speed. At the waveguides end, a strain converter transforms the strain wave into an electrical signal. Electronics correlate the waves travel time with the position of the moving magnet.
Q: What are the advantages of magnetostrictive sensors?A: Magnetostrictive position sensors provide absolute position readings, not relative values that require recalibration. This can be a big advantage in high-throughput or extreme environments.
Designers can also take advantage of the ability of magnetostrictive sensors to return the positions of multiple items simultaneously. Because the current pulse is not changed when magnetic fields interact, it can continue along the waveguide to interact with the magnetic fields of additional mobile magnets. A sensor reading multiple inputs can install more compactly and save money by only requiring a single set of signal-processing electronics.
Magnetostrictive position sensors also last longer than other sensor technolo-gies because they are non-contact and have no moving parts or parts in contact that can wear and require replacement and recalibration. Because there is no contact, there are no delicate sensing surfaces to clean or sensitivity to dirt or dust. And the use of a torsional strain wave makes the sensors less sensitive to shock and vibration.
Q: What are my options for extended temperature magnetostrictive sensors?A: Some magnetostriction position sen-sors are rated for extended tempera-tures. For instance, MTS Sensors Tem-posonics ET works up to 105C. It can be supplied with an ATEX rating for ex-plosive environments and with a 316L Stainless housing if required.
Other extended temperature options include MTS Sensors RD4 and RT4, which are good up to 100C. Both models allow for remote location of the electronics which connect to the sensing module via a wire and pipe.
FREQUENTLY ASKED QUESTIONS
Temposonics
MTS Systems Corporation,
Sensors Division
3001 Sheldon Drive
Cary, NC
Tel. 800-633-7609
www.mtssensors.com
Delivering exceptional reliability and repeatability in extended temperature conditions
Click to learn more
Model RD4
Model RT4
Model ET
Magnetostrictive Linear Position Sensors
Magnetostrictive position sensors rely on the fact that ferromagnetic materials respond
to magnetic fields with elastic microscopic strain. The interaction of two magnetic fields
sends a strain wave down the waveguide to convert into an electrical signal. Electronics
correlate travel time with the absolute position of field interaction.
How it works: Magnetostrictive position sensors
