| TEMPERATURE SENSORS |
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Should I choose a Type K or Type N thermocouple?
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What is a Pt100?
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I have an existing temperature probe, can Labfacility make a replacement?
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I have special sensor requirements, can Labfacility help?
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Are there other types of temperature sensor apart from thermocouple and PRT Types?
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Can I still purchase the old BS/ASTM colour code and why has everything gone over to IEC?
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Can Labfacility supply any installation fittings?
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How do I accurately measure a surface temperature?
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As most instrumentation only takes 2 or 3 wire Pt100s, if I took the correction made on the 3 wire system and incorporated that on to the single leg could I achieve a 4 wire system?
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If I added two identical cable lengths to a simplex sensor for two instrumentation units will I get the same reading as using a duplex sensor?
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Does Labfacility offer any publications to help technicians and students understand the choice and use of thermocouples and PRTs.
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Can I purchase a complete temperature measurement system from Labfacility?
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For thermocouple cable and connectors, why are there two colours available for the same calibration?
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Can you provide me with a sensor within 48 hours?
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Does it matter what type of steel I specify for the thermocouple sheath?
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There are several different types of extension cable construction; is the choice important?
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How can I keep abreast of new developments, products and services from Labfacility?
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How do I choose between a thermocouple and a PRT?
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How long will my sensor last in the process?
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I use many thermocouples in testing and experiments, can I make my own thermocouple junctions?
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If I have a thermowell in my process; how much distance do I allow for my Temperature sensor to suit?
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Is a sensor with a calibration certificate more accurate than an uncalibrated one?
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My PRT is 1kOhm @ 0oC (Pt1000), not 100 Ohm (Pt100), can Labfacility supply an equivalent?
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My thermocouple is sited a long way from my controller, is this a problem?
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What accuracy loss will I get using a transmitter in line?
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What accuracy will I get at a certain temperature using a Pt100 detector; if a better grade detector is used what effect will this have to the accuracy?
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What do the thermocouple terms "cold junction compensation" and "linearisation" mean?
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What environments are 303,304,310,316,321, Inconel 600 and Nicrobell Suited to?
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What is the difference between a fabricated thermopocket and solid drilled Thermowell?
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What is the difference between a flat film and wire wound element?
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What is the minimum immersion depth for a PRT probe?
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What is the difference between a RTD and PRT sensor?
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What is the difference between Mineral Insulated (MI) and a fabricated sheath?
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What is the longest thermocouple I can have without losing accuracy?
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What is the practical difference between wire-wound and film RTDs?
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What type of Compression Fittings are available?
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What typical pressure are thermowells / thermopockets rated to and what is the Thermal response time of the thermowell?
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Which thermocouple type do I need for my application?
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Why are so many different types of thermocouple used?
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Why offer 2,3 or 4 wire PRTs
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Why should I use actual thermocouple connectors instead of ordinary electrical connectors?
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What sensor will I need to work in molten metal or a corrosive atmosphere?
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Why should I use an insulated hot junction sensor with instrumentation?
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Why specify a Swaged Tip?
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Why use a Bayonet Fitting to install a probe..?
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Why use a Compression Fitting to fit a probe into a process?
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Why use a thermowell?
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Do I need a power supply when using a transmitter, and what length of extension lead can I run with a transmitter fitted?
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Does Labfacility offer a weatherproof, rugged sensor?
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How accurately can I measure temperature using a Labfacility sensor?
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I need to measure quickly changing temperature; what type of sensor should I use?
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What is a duplex sensor?
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| QUESTIONS & ANSWERS |
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Should I choose a Type K or Type N thermocouple?
Generally, Type N is more stable and usually lasts longer than Type K; N is a better choice for high temperature work depending on the choice of sheath material.
Labfacility E-mail Newsletter - click here for registration. |
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What is a Pt100?
An industry standard Platinum RTD with a value of 100 Ohms @0oC to IEC751; this is used in the vast majority of PRT assemblies in most countries.
Labfacility E-mail Newsletter - click here for registration. |
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I have an existing temperature probe, can Labfacility make a replacement?
Yes, if it is a thermocouple or PRT. All we need is a sample, sketch or specification in order to quote.
Labfacility E-mail Newsletter - click here for registration. |
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I have special sensor requirements, can Labfacility help?
Yes, we have 30 years of experience of sensor design and application. |
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Are there other types of temperature sensor apart from thermocouple and PRT Types?
Several, but these two groups are the most common. Alternatives include thermistors, infra-red (non-contact), conventional thermometers (stem & dial types) and many others. |
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Can I still purchase the old BS/ASTM colour code and why has everything gone over to IEC?
Labfacility can supply some products to the "old" obsolete BS colour but the current IEC standard is internationally recognised.
click here for the IEC colour codes
Labfacility E-mail Newsletter - click here for registration. |
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Can Labfacility supply any installation fittings?
We manufacture installation fittings on site at the Bognor Regis branch and offer either from Stock or bespoke. |
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How do I accurately measure a surface temperature?
Use an infra-red (non-contact) sensor instead of a thermocouple or PRT. - contact technical sales. |
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As most instrumentation only takes 2 or 3 wire Pt100s, if I took the correction made on the 3 wire system and incorporated that on to the single leg could I achieve a 4 wire system?
No; cable length and ambient temperature variations come into play.
Labfacility E-mail Newsletter - click here for registration. |
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If I added two identical cable lengths to a simplex sensor for two instrumentation units will I get the same reading as using a duplex sensor?
Yes, provided the instrument inputs are truly potentiometric and no measuring current is drawn. Not recommended.
Labfacility E-mail Newsletter - click here for registration. |
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Does Labfacility offer any publications to help technicians and students understand the choice and use of thermocouples and PRTs.
Yes, the Labfacility Temperature Handbook - To receive your free copy click here
Labfacility E-mail Newsletter - click here for registration.
ALL Labfacility Brochures now available in a PDF downloadable format - click here |
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Can I purchase a complete temperature measurement system from Labfacility?
Yes, there is a wide choice depending on budget and application requirements.
Labfacility E-mail Newsletter - click here for registration. |
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For thermocouple cable and connectors, why are there two colours available for the same calibration?
Since December 1998, the International colour code to IEC 60584-3 should be observed.
Labfacility E-mail Newsletter - click here for registration. |
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Can you provide me with a sensor within 48 hours?
Yes. You can order from our stock range of sensors; if you need an alternative we can provide a custom-made alternative within 7/10 days.
Labfacility E-mail Newsletter - click here for registration. |
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Does it matter what type of steel I specify for the thermocouple sheath?
Often no, sometimes yes. In some cases, reliability depends on the ideal choice of material - contact "technical sales". |
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There are several different types of extension cable construction; is the choice important?
Yes; some are waterproof, some mechanically stronger, some suitable for high or low temperature -
Click here to contact our sales team
Labfacility E-mail Newsletter - click here for registration.
**View PDF Literature on the new PDF Feature button on our Home Page ** |
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How can I keep abreast of new developments, products and services from Labfacility?
Labfacility E-mail Newsletter - click here for registration.
NOTE: Our PDF Feature button on the website is regularly being updated with new Labfacility Product Literature |
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How do I choose between a thermocouple and a PRT?
Mainly on the basis of required accuracy, probe dimensions, speed of response and the process temperature - refer to the Labfacility Temperature Handbook for full guidance. |
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How long will my sensor last in the process?
Not known but predictable in some cases; this will be a function of sensor type, construction, operating conditions and handling. Contact "technical sales".
Labfacility E-mail Newsletter - click here for registration. |
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I use many thermocouples in testing and experiments, can I make my own thermocouple junctions?
Yes, Labfacility can supply a benchtop welder and fine thermocouple wires - it is easy and inexpensive to make unsheathed thermocouples.
For more information click here
Labfacility E-mail Newsletter - click here for registration. |
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If I have a thermowell in my process; how much distance do I allow for my Temperature sensor to suit?
An extra 50mm for a compression gland if used or probe length to fully seat into the well if a thread below head.
Labfacility E-mail Newsletter - click here for registration. |
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Is a sensor with a calibration certificate more accurate than an uncalibrated one?
No. However, the errors and uncertainties compared with a reference sensor are published and corrected values can be used to obtain better measurement accuracy.
Labfacility E-mail Newsletter - click here for registration. |
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My PRT is 1kOhm @ 0oC (Pt1000), not 100 Ohm (Pt100), can Labfacility supply an equivalent?
Yes, and some other values as well.
Labfacility E-mail Newsletter - click here for registration. |
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My thermocouple is sited a long way from my controller, is this a problem?
It could be; try to ensure a maximum sensor loop resistance of 100 Ohms for thermocouples and 4-wire PRTs. Exceeding 100 Ohms could result in a measurement error. Note By using a 4-20mA transmitter near the sensor, cable runs can be much longer and need only cheaper copper wire. The instrument must be suitable for a 4-20mA input though.
Labfacility E-mail Newsletter - click here for registration. |
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What accuracy loss will I get using a transmitter in line?
This depends on the accuracy of the specified transmitter; there will always be some degradation - consult Technical Sales.
Labfacility E-mail Newsletter - click here for registration. |
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What accuracy will I get at a certain temperature using a Pt100 detector; if a better grade detector is used what effect will this have to the accuracy?
Refer to the Labfacility Temperature Handbook for Pt100 tolerance information.
To apply for your free copy simply click here
Labfacility E-mail Newsletter - click here for registration. |
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What do the thermocouple terms "cold junction compensation" and "linearisation" mean?
Refer to the Labfacility Temperature Handbook for a full explanation. With most types of measuring instrument, these functions are automatically applied and do not require user consideration.
Labfacility E-mail Newsletter - click here for registration.
Get your free copy now simply click here and follow the on screen instructions. |
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What environments are 303,304,310,316,321, Inconel 600 and Nicrobell Suited to?
Depends on a combination of temperature and media. Consult technical sales.
Labfacility E-mail Newsletter - click here for registration. |
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What is the difference between a fabricated thermopocket and solid drilled Thermowell?
A fabricated thermopocket uses a welded construction to allow for relatively long immersion lengths; a thermowell is machined from solid material.
Labfacility E-mail Newsletter - click here for registration. |
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What is the difference between a flat film and wire wound element?
Film uses platinum deposition on a substrate; wire wound uses a helically wound Pt wire in ceramic. Wire-wound type provides greater accuracy and stability but is vulnerable to shock; film type is resistant to shock and has quicker thermal response.
Labfacility E-mail Newsletter - click here for registration. |
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What is the minimum immersion depth for a PRT probe?
Usually 150mm or more; increase the immersion until the reading is unchanged.
Labfacility E-mail Newsletter - click here for registration. |
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What is the difference between a RTD and PRT sensor?
Nothing. RTD means resistance thermometer detector (the sensing element) and PRT means Platinum resistance thermometer (the whole assembly) i.e. a PRT uses a RTD!
Labfacility E-mail Newsletter - click here for registration. |
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What is the difference between Mineral Insulated (MI) and a fabricated sheath?
An MI is flexible, a fabricated sheath is rigid.
Labfacility E-mail Newsletter - click here for registration. |
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What is the longest thermocouple I can have without losing accuracy?
It could be; try to ensure a maximum sensor loop resistance of 100 Ohms for thermocouples and 4-wire PRTs. Exceeding 100 Ohms could result in a measurement error. Note By using a 4-20mA transmitter near the sensor, cable runs can be much longer and need only cheaper copper wire. The instrument must be suitable for a 4-20mA input though. |
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What is the practical difference between wire-wound and film RTDs?
Wire-wound type provides greater accuracy and stability but is vulnerable to shock; film type is resistant to shock and has quicker thermal response.
Labfacility E-mail Newsletter - click here for registration. |
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What type of Compression Fittings are available?
Stainless Steel and Brass alternatives- please see our TURNED PARTS brochure for our product range. |
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What typical pressure are thermowells / thermopockets rated to and what is the Thermal response time of the thermowell?
Typically tens of bar and tens of seconds more than the sensor. Refer to a full supplier specification however - values vary.
Labfacility E-mail Newsletter - click here for registration. |
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Which thermocouple type do I need for my application?
This depends on several factors including the nature of the process, heated medium and temperature. Refer to the Labfacility Temperature Handbook.
Labfacility E-mail Newsletter - click here for registration. |
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Why are so many different types of thermocouple used?
They have been developed over many years to suit different applications world-wide.
Labfacility E-mail Newsletter - click here for registration. |
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Why offer 2,3 or 4 wire PRTs
Because all 3 are encountered. Two-wire should be avoided, three-wire is widely used and four-wire gives optimum accuracy. Your instrument will be configured for 2,3 or 4 wire. |
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Why should I use actual thermocouple connectors instead of ordinary electrical connectors?
Labfacility thermocouple connectors use thermocouple alloys, polarized connections and colour coded bodies to guarantee perfect, error-free interconnections.
FULL Technical specifications are shown within the 12 page THERMOCOUPLE & CABLE BROCHURE - available upon request and in downloadable PDF Format via the PDF button on the Labfacility website.
Labfacility E-mail Newsletter - click here for registration. |
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What sensor will I need to work in molten metal or a corrosive atmosphere?
There is no simple answer but special grades of Stainless Steel, Inconel 600, Nicrobell and Ceramics offer alternatives - consult Technical Sales. |
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Why should I use an insulated hot junction sensor with instrumentation?
To eliminate the possibility of earth loops resulting in measurement errors and to reduce the danger of voltage pick up from electrical heaters. |
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Why specify a Swaged Tip?
To obtain good Thermal Coupling ( better response) with the medium whilst retaining good mechanical strength in the probe assembly. |
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Why use a Bayonet Fitting to install a probe..?
To achieve a quick fit / changeover |
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Why use a Compression Fitting to fit a probe into a process?
Use a Tapered Thread to obtain high pressure integrity or a Parallel Thread for general purpose. |
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Why use a thermowell?
To protect the sensor from the process medium and to facilitate its replacement if necessary.
Labfacility E-mail Newsletter - click here for registration. |
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Do I need a power supply when using a transmitter, and what length of extension lead can I run with a transmitter fitted?
A 24Vdc, 20mA supply will be needed if this is not incorporated in the measuring instrument. Long runs of copper cable can be used.
Labfacility E-mail Newsletter - click here for registration. |
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Does Labfacility offer a weatherproof, rugged sensor?
We manufacture a wide range of weatherproof, rugged sensors. For more details on our range contact our Sales Team who will be pleased to advise you on the best solution for your apllication.
Labfacility E-mail Newsletter - click here for registration.
To contact the Sales Team simply click here |
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How accurately can I measure temperature using a Labfacility sensor?
To published, internationally specified tolerances as standard, typically ( 2.5oC for popular thermocouples, (0.5oC for PRT. Higher accuracy sensors can be supplied to order, e.g. (0.5oC for type T thermocouple, (0.2oC for PRT. All of these values are temperature dependent. A close tolerance, 4-wire PRT will give best absolute accuracy and stability. Contact our
"technical sales" for help.
Labfacility E-mail Newsletter - click here for registration. |
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I need to measure quickly changing temperature; what type of sensor should I use?
A fast-response (low thermal mass) thermocouple.
Labfacility E-mail Newsletter - click here for registration. |
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What is a duplex sensor?
One with two separate sensors in a single housing.
Labfacility E-mail Newsletter - click here for registration. |
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