Temperature Measurement with your Computer

Windmill LogoOne of the best of our favorite resources on the Web is a software company on Manchester, England, Windmill Software. They have supplied free PC software for Test & Measurement to all who wish to download it from their website: http://www.windmill.co.uk,

Windmill has for many years also published a free monthly informative eNewsletter called Monitor newsletter (ISSN 1472-0221); archive and subscription available online at http://www.windmill.co.uk/newsletter.html.

At last look it was up to issue No, 224!

Here’s links to one of the extra specials they have done on the subject of temperature measurement

(Excerpt)

Measuring Temperature with a Computer

Temperature measurement is the most common application of data acquisition systems. You will need a device to measure the temperature – a temperature sensor. Thermocouples, resistance temperature devices (RTDs), thermistors, platinum resistance thermometers and infrared thermometers are all types of temperature sensor.

The most popular are thermocouples and RTDs. The sensors you choose depends on several things, such as as your expected maximum and minimum temperatures, cost, accuracy needed and your environmental conditions.

To get data from the temperature sensor into your PC you need a data acquisition interface with suitable software. The interface unit plugs into your computer, for example into the USB or Ethernet port.

You wire the sensor to the interface, install the software and the computer can now monitor temperatures.


Comparison of Thermocouples and RTDs

IMPROVING HUMIDITY MEASUREMENTS IN METEOROLOGY

A product with a unique advantage

EE33 sensor tube - thermal image
EE33 sensor tube – thermal image

Air humidity and temperature play an important role in meteorology. Highly accurate measurements of these climate parameters form the basis of accurate forecasts and meaningful records.

The E+E Elektronik Model EE33 series humidity and temperature sensor is the only one on the market with a double-heated probe. Both the sensor tube and the sensor element are heated.

An application note, free for download from their website, tells the rest of the story.

You can download it be clicking here.

If that does not work, as sometimes happens when organizations “refine” their websites, we have archived a copy in our database; it may be downloaded here: Humidity_measurement_meteorology

Related technical webpages & download from E+E Elektronik:

E+E Elektronik – the Sensor specialist for humidity sensors, CO2 sensors, moisture in oil, dew point, air velocity, flow and temperature sensors. As a specialist for sensors E+E Elektronik produces humidity sensorsCO2 sensorsflow sensors, transmitters, hand-held meters and  dataloggers for the measurement of relative humiditymoisture in oildewpoint,
air velocityflowCO2 and temperature. E+E also operates a nationally accredited calibration lab and is appointed to maintain the “National Standard for Humidity and Air Flow Speed in Austria”

World HQ

E+E Elektronik Ges.m.b.H.
Langwiesen 7
A-4209 Engerwitzdorf
Austria

Tel: +43 (0)7235 605-0
Fax: +43 (0)7235 605-8
E-mail: info@epluse.com
Website: www.epluse.com

USA

E+E Elektronik Corp.
124 Grove Street
Franklin, MA 02038
United States

Tel: +1 508 530 3068
Fax: +1 508 346 3798
E-mail: gleighton@epluse.com

Using a 3-Wire RTD to Reduce Temperature Measurement Errors

Ensure High Accuracy in Your Critical Temperature Measurements

DataloggerCHESTERLAND OH, USA — To prevent inaccurate temperature measurements which can potentially cause disastrous inventory losses, CAS DataLoggers recommends using 3-wire RTDs to customers taking temperature measurements using RTD sensors.

These sensors are affordable and easily available for use with our wide inventory of temperature dataloggers, but some users are unaware of this more accurate option. With this in mind, Applications Specialists have put together this brief guide to show the need for 3-wire RTDs.

RTD sensors make simple resistance measurements, usually at about 100 ohms, which is a relatively low level of resistance. Therefore an RTD measurement error of 1 ohm or more is quite significant, for a regular RTD at room temperature, the resistance is 109.1 ohms, and even a 1-ohm error in that measurement will cause a temperature error of about 2.5 °C.

When using a 2-wire RTD, users may find that the resistance of the connections between the sensor and datalogger directly affects the temperature measurement, so this is easily avoided by using a 3-wire RTD, which enables the connected datalogger to compensate for the resistance of the circuit.

An example of this kind of measurement error occurs when connecting an RTD to a piece of 20 AWG (American Wire Gauge) copper hookup wire (solid or stranded), with electrical resistance* of about 1 ohm per 100 ft. of length.

In this case, using a 2-wire RTD with a 50-ft cable on it can result in a 2 ° to 2.5 °C systematic temperature error just due to the resistance of the wire.

So, especially with longer cable runs, users can avoid this significant error source by using a 3-wire RTD sensor along with a data logger that provides automatic compensation for these types of applications.

* Reference the electrical resistance of copper wire versus AWG size on the HyperPhysics website at: hyperphysics.phy-astr.gsu.edu/hbase/tables/wirega.html (NOTE:  HyperPhysics is a free online educational resource by Dr. Rod Nave at the Georgia State University in Atlanta GA, USA.  A CD/DVD version  is available for purchase at: http://hyperphysics.phy-astr.gsu.edu/hbase/hph.html#ahph. Apps for iPhone and iPad are also available at small or moderate cost at Apple’s iTunes store.)

CAS DataLoggers products are used in a wide variety of applications in remote monitoring, in industrial process and manufacturing industries, for automotive and aerospace data collection, in pharmaceutical manufacturing and storage, and in geological and environmental monitoring—there are even units on the Space Shuttle and ISS (International Space Station)!

Sophisticated data acquisition and control systems are also available including high performance real-time systems for situations where traditional test systems or programmable controllers are not suitable.

These systems are used in data acquisition, test and control applications where microsecond precision is needed. Models are available with 8 to over 400 analog input channels, analog output channels, digital inputs and outputs, counters, RS-232, RS-485 CANbus and Profibus interfaces. CAS DataLoggers also provides configuration assistance, custom programming, custom system design and assembly, post-sales technical support, and repair and calibration services. Development capabilities include custom data acquisition and data logging systems, test and measurement systems, and portable data collection systems.

For more information on a wide range of temperature dataloggers from Accsense, T&D, Grant and more, or to find the ideal solution for your application-specific needs, contact a CAS Data Logger Applications Specialist at (800) 956-4437 or visit the website at www.dataloggerinc.com.

Contact Information:
CAS DataLoggers, Inc.
12628 Chillicothe Road
Chesterland, Ohio 44026

Tel: +1 (440) 729-2570 and, Toll-free: (800) 956-4437
Email: sales@dataloggerinc.com
Website: www.dataloggerinc.com

Data Translation, Inc.

dtlogo

Data Translation,founded in 1973 and headquartered in Marlboro, Massachusetts, USA, is a leading designer, manufacturer, and provider of data acquisition solutions for test and measurement. With expertise in the design of high-accuracy, high-quality hardware and application software, Data Translation partners with end users and OEMs to achieve their test and measurement goals.
Data Translation has a worldwide presence, with offices in the US and Europe and distribution in more than 40 countries. Data Translation products are manufactured in the USA.

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