World Class Resistance Temperature Detectors
RTD Products
www.rtd-products.co.uk
RTD Products - Company Overview RTD products is one of the world’s leading manufacturers of ceramic wire wound platinum Resistance Temperature Detectors (RTD). If you require high precision, low drift and long lifetime from your temperature measuring device for temperatures between -200°C and 600°C then RTDs are the only measuring device that fit these needs currently available on the market. All our RTDs are handmade at our manufacturing plant in Southport, UK where we work to the regulations of the International Electrochemical Commission (IEC). Our in-house knowledge and experience along with our passion for world class quality and customer service has been key to our continuous growth and success. We trade on and are proud of the quality of our products and our product excellence is proven by our long standing worldwide customer base which is supported by a global sales presence. Our dedicated sales and customer service team ensure that all our customers have the right RTD solution for them, delivered on time. Along with our devoted and reliable customer service team we also have a technical support team available to support customers requiring more practical information. If you require the highest and most reliable quality of RTD, along with unrivalled sales, customer service and technical support team please do not hesitate to contact our sales team or consult our website for further information.
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What is an RTD? RTDs are precision temperature sensors that exploit the predictable change in electrical resistance of some materials with changing temperature. They consist of a sensing element, wires to connect the sensing element to the measurement instrument and some kind of support to position the sensing element in the process. RTDs make use of the fact that the resistance of metals changes depending on the temperature. The metal element in RTDs is usually made of platinum. This is because platinum is very stable, has a high temperature rating, near linear relationship between resistance and temperature, can be heated and cooled repeatedly without negative effects and is not affected by corrosion or oxidation. The resistance change of platinum changes in a positive and linear fashion making it a perfect material for measuring temperature difference because it is known that for each increase in temperature there is a directly proportional increase in resistance. RTDs are commonly used temperature sensors, and their use is widespread throughout numerous industries including oil and gas, food, chemical and pharmaceutical. RTDs are selected for use when:
- accuracy and stability are key for measurement of the temperature of the application
- accuracy must extend over a wide temperature range
- area rather than point sensing improves control
- a high degree of standardization is desirable
Their key advantages are:
- Linear over a wide operating range
- Large temperature operating range
- High accuracy
- Low drift
- Suitable for precision applications
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Industry Standards The IEC (International Electrotechnical Committee) 60751:2008 standard is a key industry standard. This standard works on the basis of the temperature coefficient of platinum being 0.00385 ohms/ ohms/°C. (Other standards include AFI, SAMA, JIS). The alpha value changes depending on the grade of platinum used. The most common type of RTD sensor is known as the Pt100 this is because the sensor has a resis3.5 tance of 100 ohms at 0°C. (However, there are RTDs with base resistance of 500 or 1000 ohms on the market). Both DIN and JIS use base resistance of 100 ohms at 0°C. 3
DIN standard platinum has a temperature coefficient – often referred to as the Alpha (α) value - of 2.5 0.00385 ohms/ohms/°C. This means that a 100 ohm platinum RTD will increase in resistance by Class B 0.00385 ohms for every 1°C of temperature increase. So at 0°C the resistance is 100 ohms, at 100°C Class A resistance =2 138.5 ohms. Thus the DIN standard resistance vs temperature curve is 0.003851/3 ohms/ ohms/°C. 1/5 1/10
1.5
JIS standard platinum has a temperature coefficient –Alpha (α) value - of 0.003916 ohms/ohms/°C. This means1that a 100 ohm platinum RTD will increase in resistance by 0.003916 ohms for every 1°C of temperature increase. So at 0°C the resistance is 100 ohms, at 100°C resistance = 139.16 ohms. Thus 0.5 the JIS standard resistance vs temperature curve is 0.003916 ohms/ohms/°C. A quick explanation of how the coefficient is derived is as follows: Resistance at the boiling point 0 -200 -100 0 200(0ºC) = 300 600 difference (38.5) by 100 (100ºC) =138.50 ohms. Resistance at100 ice point 100.00400 ohms. 500 Divide the degrees and then divide by the 100 ohm nominal value of the element. The result is the mean temperature coefficient (alpha) of 0.00385 ohms per ohm per ºC. 400 350 300
Resistance Ω
250 200 150 100 50 0 -200
-100
0
100
200
300
400
500
600
700
800
Temperature °C
Fig 1. Resistance Temperature Curve for 100Pt Platinum RTD (α = 0.00385)
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RTD Tolerances The accuracy or more accurately the tolerance of these sensors can differ. Thus to enable the tolerance of the sensors to be known a classification system has been developed. The IEC system is seen as the industry standard. The IEC (International Electrotechnical Committee) has industry standard classes of W0.1, W0.15, W0.3 and W0.6. These classes translated as follows in terms of resistance and temperature tolerances: IEC Standard
DIN4370
Temperature Range °C
Tolerance Ω at 0°C
Tolerance °C at 0°C
W0.03
1/10 Din
-100 to 350
100 ±0.012Ω
±0.03°C
W0.1
1/3 Din
-100 to 350
100 ±0.04Ω
±0.10°C
W0.15
Class A (1/2 Din)
-100 to 450
100 ±0.06Ω
±0.15°C
W0.3
Class B (Din)
-196 to 660
100 ±0.012Ω
±0.30°C
W0.6
Class C
-196 to 660
100 ±0.23Ω
±0.60°C
Thus for W0.15 or Class A RTDs the margin of error of a reading at 0°C is ±0.15°C or ±0.06Ω. So a class A RTD that reads a resistance of 99.96 or 100.06 is giving a temperature reading of 0°C, tolerant to class A specifications of the IEC standards. An RTD reading a resistance value of 99.78 at 0°C it would be classed as a W0.6 tolerant RTD. 3.5
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2.5 Class B Class A
2
1/3 1/5 1/10
1.5
1
0.5
0 -200
-100
0
100
200
300
400
500
600
Fig 2. Tolerances 400 350 300
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RTD Product Range Standard (2 wire)
DUPLEX (4 wire)
Diameter (mm)
Length (mm)
Lead diameter (mm)
Lead Resistance
Sensing Length
PR0815
0.08
15
0.15
0.006398
13
PR0915
0.09
15
0.15
0.006398
13
PR1210
1.20
10
0.23
0.002721
8
PR1215
1.20
15
0.23
0.002721
13
PR1408
0.00
PR1415 PR1415D PR1425 PR1425D PR1515 PR1515D
15
0.23
0.002721
13
1.40
15
0.25
0.002303
13
1.40
25
0.23
0.002721
22
1.40
25
0.25
0.002303
22
1.50
15
0.23
0.002721
13
1.50
15
0.25
0.002303
13
PR1608
1.50
8
0.25
0.002303
8
PR1615
1.60
15
0.23
0.002721
13
1.60
15
0.25
0.002303
13
1.60
25
0.23
0.002303
22
1.60
25
0.25
0.002303
22
PR1615D PR1625 PR1625D PR2006
2.00
6
0.25
0.002303
6
PR2015
2.00
15
0.35
0.001175
13
2.80
15
0.35
0.001039
13
PR2015D PR2808
2.80
8
0.35
0.001039
8
PR2815
2.80
15
0.35
0.001039
13
2.80
15
0.35
0.001039
13
2.80
25
0.35
0.001039
22
2.80
25
0.35
0.001039
22
PR3008
3.00
8
0.35
PR3015
3.00
15
0.35
0.001039
13
3.00
15
0.35
0.001039
13
3.00
25
0.35
0.001039
22
3.00
25
0.35
0.001039
22
PR2815D PR2825 PR2825D
PR3015D PR3025 PR3025D PR3208
3.20
8
0.35
0.001039
8
PR3215
3.20
15
0.35
0.001039
13
3.20
15
0.35
0.001039
13
3.20
25
0.35
0.001039
22
3.20
25
0.35
0.001039
22
3.80
15
0.35
0.001039
13
3.80
15
0.35
0.001039
13
3.80
25
0.35
0.001039
22
3.80
25
0.35
0.001039
22
4.50
15
0.35
0.001039
13
4.50
15
0.35
0.001039
13
4.50
30
0.35
0.001039
26
PR3215D PR3225 PR3225D PR3815 PR3815D PR3825 PR3825D PR4515 PR4515D PR4530
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1.40
Our standard* Platinum RTD Product Range is available in: •• 2 and 4 wire assemblies •• IEC Classes:
W0.6, W0.3, W0.15, W0.1, W0.06 and W0.03
•• DIN Classes: Class C, B, A, 1/3 Din, 1/5 Din, 1/10 Din •• Lead length 7mm •• Temperature Range: -200°C to +600°C •• Pre-aged. •• Standard Calibration Point: 5mm from ceramic body •• Calibrated to IEC specifications •• Manufactured and tested to IEC specifications All RTDs are partially supported by aluminum oxide glass All RTDs are supplied with 4 lead wires to avoid resistance pollution All products are batch coded in order to ensure traceability Products are packaged to ensure safe and damage free delivery *Customer specific assemblies and tolerances are available on request RTD Products is proud of its quality ethos and believes its combination of high quality product along with a supportive sales and customer service team ensure our customers are always satisfied. Along with RTDs of the highest quality we offer: •• A dedicated and knowledgeable sales team – keen to discuss best options and solutions for customers’ needs •• Aftersales service: • customer service – allowing customers to have any information required on past, current and future orders • technical support team – giving customers technical support such as best practices for fitting the RTD or troubleshooting •• A standard lead time of 2 weeks •• Premium delivery option – shipped within 48 hrs of receiving order
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RTD Products, part of the British Rototherm Group of Companies, is the UK’s leading manufacturer of platinum resistance temperature detectors and associated products. From our factory in Southport, Merseyside, the highest quality platinum resistance temperature detectors are manufactured and sent across the world. All devices are manufactured from traceable materials and their construction is controlled by our BS EN ISO 9001: 2008 approved Quality System, using the latest techniques in production and testing.
RTD Products
TM
ISO9001:2008
RTD Products
Units 10 & 11 A K Business Park, Russell Road Southport, Merseyside PR9 7SA Telephone: Facsimile: E-mail us :
+44 (0) 1704 507696 +44 (0) 704 507055 sales@rtd-products.co.uk
RTD Products is part of the British Rototherm Group of Companies British Rototherm Co. Ltd. Kenfig Industrial Estate, Margam, Port Talbot SA13 2PW United Kingdom Registered in the UK. 2570730 at the above address. In keeping with RTD Products policy for continual product development and improvement, we reserve the right to amend specifications without notice. Š2011 RTD Products. All rights reserved. Company registered in Wales : 2570730.