Mineral Insulated Resistance Thermometers:-

   High Accuracy and Stability

   Good Linearity

   No Compensating Cable

   No Cold Junction Compensation

General Description

Platinum Resistance Sensors offer the highest standard of accuracy and stability of any temperature sensor. They also exhibit good linear response, covering a temperature range from -200ºC to +650ºC. They are easy to apply and require no special cables or cold junction reference. Platinum resistance sensors are finding increasing favour in industry, where their high accuracy, repeatability and stability are vital. Our minerally insulated RTDs are manufactured from superior grade materials. In addition we provide technical expertise, advice, design and a manufacturing facility second to none.

RTD Types:-

The following types of RTD are available:

PT100

 - 

Platinum, 100W at 0ºC

PT1000

Platinum, 1000W at 0ºC

Cu100

Copper, 100W at 0ºC

Ni100

Nickel, 100W at 0ºC

Applicable standards:-

Resistance Values

IEC 60751:1983

DIN 43760

Tables of resistance values for PT100 RTDs are available from Jagjan. Refer to Technical Data Sheet JAG/PTT. 

Manufacture:- 

IEC 60751:1983

Tolerances:-

IEC 60751:1983

DIN : 43760

Resistance Detectors

A wide range of sizes are available, down to as small as 1.5 mm diameter. Duplex executions are produced in several sizes. 

Jagjan Temperature Detectors are capable of withstanding vibration and acceleration levels of up to 30g over the frequency range 10Hz to 1kHz. Detector accuracy will remain unaffected by large changes in pressure.

Detectors are available as standard in tolerance classes A and B. 

Sheaths and Conductors:-

RTDs are available in 2, 3 or 4 wire configurations with a range of sheath materials and conductor materials. Standard sheath materials include 316 Stainless Steel, 310 Stainless Steel and Inconel 600. For high temperature applications, a nickel sheath is preferred. Conductors are usually either silver plated copper or silver. The tables below show the most common sheath/conductor combinations. These are readily available from Jagjan.

RTD - 2 Wire Configuration
Sheath Material Outside Diameter 
4.5 6.0 8.0
316 Stainless Steel

Œ

Œ Œ
310 Stainless Steel

Œ

Œ

Œ

Inconel® 600

Œ

Œ

Œ

 

RTD - 3 Wire Configuration
Sheath Material Outside Diameter 
4.5 6.0 8.0
316 Stainless Steel

Œ

Œ Œ
310 Stainless Steel

Œ

Œ

Œ

Inconel® 600

Œ

Œ

Œ

 

RTD - 4 Wire Configuration
Sheath Material Outside Diameter 
4.5 6.0 8.0
316 Stainless Steel

Œ Œ
310 Stainless Steel

Œ

Œ

Inconel® 600   1

Œ

                 Œ= Simplex

                                                          = Duplex

High Temperature RTDs :-

At temperatures above 500ºC, the platinum wires used in the construction of RTD elements are susceptible to ‘poisoning’ from a variety of sources. The result is rapid drifting of the reading, normally upwards. The most common causes are:-

The sheath material - iron vapour contamination effectively rules out the use of stainless steels and most nickel alloys. Pure nickel is the preferred material.

Oil and grease traces of oil left inside the protecting tube, or on the element itself, give off poisonous gases at high temperature. Absolute cleanliness is essential in RTD production.

Tolerances

Tolerances for PT100 Resistance Temperature Detectors are shown below in tabular and  graphical format.

Temp oC

Tolerance

CLASS B CLASS A 1/3 DIN 1/5 DIN 1/10 DIN

± Oc

± W

± Oc

± W

± Oc

± W

± Oc

± W

± Oc

± W

-200 1.3 0.56 0.55 0.24 0.44 0.19 0.26 0.11 0.13 0.06
-100 0.8 0.32 0.35 0.14 0.27 0.11 0.16 0.06 0.08 0.03
0 0.3 0.12 0.15 0.06 0.10 0.04 0.06 0.02 0.03 0.01
100 0.8 0.30 0.35 0.13 0.27 0.10 0.16 0.05 0.08 0.03
200 1.3 0.48 0.55 0.20 0.44 0.16 0.26 0.10 0.13 0.05
300 1.8 0.64 0.75 0.27 0.60 0.21 0.36 0.13 - -
400 2.3 0.79 0.95 0.33 0.77 0.26 - - - -
500 2.8 0.93 1.15 0.38 - - - - - -
600 3.3 1.06 1.35 0.43 - - - - - -
650 3.6 1.13 1.45 0.46 - - - - - -
700 3.8 1.17 - - - - - - - -
800 4.3 1.26 - - - - - - - -
850 4.6 1.34 - - - - - - - -

Fittings :-  A wide range of termination glands and adjustable compression fittings are available to suit RTDs of all diameters.

Sliding Compression Fitting

Transmitter Baseplates :-  

RTDs can be manufactured with DIN mounting plates to suit temperature transmitters. 

Moulded Plugs :- 

The Heavy Duty plug is a standard round pin moulded plug suitable for  4.5 mm and 6.0 mm diameter RTDs. Maximum ambient temperature is 270ºC. A duplex version is also available. A miniature version is also available, with flat pins.

Both standard and miniature connections can be supplied in socket end versions. An alternative range of high temperature plug and socket combinations is available with ceramic bodies.

Standard Seals :- 

A wide variety of standard and custom designed seals can be manufactured to suit specific applications.

The C Pot is a stainless steel crimped-on epoxy resin seal, suitable for 4.5 mm and 6.0 mm diameter RTDs.

Maximum ambient temperature is 85ºC when fitted with PVC tail wires and 180ºC when fitted with PTFE tail wires and high temperature epoxy. 

Threaded Seals :-  

The A Pot is an M8 threaded epoxy resin seal for  4.5 mm RTDs. 

The B Pot is an M10 threaded epoxy resin seal for  4.5 mm and 6.0 mm, or 8.0 mm RTDs. Locknuts can be supplied. Maximum ambient temperature is 85ºC when fitted with PVC tail wires and 180ºC when fitted with PTFE tail wires and high temperature epoxy. 

Wiring Configurations :-

2-Wire Connection :- 

This method allows NO compensation for lead resistance, which is effectively added to the thermometer resistance. 

Only suitable for low accuracy applications such as domestic appliances, motor vehicles or where lead lengths are very short. Typically leads made from 7/0.2mm copper will add a positive offset of almost 0.5ºC/m.

 3-Wire Connection :-

By far the most common configuration for industrial applications, the 3-wire system allows for effective compensation of lead resistance and also compensates for changes in lead resistance 

when wires pass through temperature variations (temperature coefficient of resistance of copper is greater than platinum).  Remaining errors with this system are mostly due to variations in resistance between the 3 wires.

4-Wire Connection :-

Must be used when the highest accuracy is needed, particularly where lead runs are long, providing almost total rejection of lead resistance and temperature effects.

This system is becoming more common as "Intelligent Transmitters" become more popular, as these almost always can use the 4-wire system.

Mineral insulated resistance sensors are becoming much more popular in recent years, for their robust, vibration resistant properties, these are normally made using 4 core MI cable, so there is no economic reason not to use all four.

 

4-Wire Compensated :-

An unusual system where a "Compensating Loop" of wire, equal in resistance to the thermometer leads is connected to balance their effect. This is normally achieved in a bridge circuit, by connecting the loop in the opposite leg to the sensor.

The method can give good results, but is not commonly used with modern instrumentation.