Description
Resistance thermometers in this series are designed for screw fitting into air ducts.
Due to the perforation of the thermowell the measurement insert is in direct contact with the media. This improves considerably the response time. The measuring insert is
sealed to the connection head which means no media can leak out.
Insertion length, process connection, design of thermowell, connection head as well as type and number of sensors, accuracy and method of connection can be selected
individually for the respective application.
Optionally we can fit analogue or digital transmitters from the WIKA range into the connection head of the TR10-J.
Sensor
The sensor is located in the tip of the measuring insert.
Sensor method of connection
2-wire The lead resistance of the measuring insert
compounds the error.
3-wire With a cable length of approx. 30 m or longer
measuring deviations can occur.
4-wire The inner lead resistance of the connecting
wires is negligible.
Sensor limiting error
Class B to DIN EN 60 751
Class A to DIN EN 60 751
1/3 DIN B at 0 °C
It makes no sense to combine 2-wire connection with class A or 2-wire connection with 1/3 DIN B, because the lead resistance of the measuring insert, over-rides the
higher sensor accuracy.
Basic values and limiting errors Basic values and limiting errors for the platinum measure-
ment resistances are laid down in DIN EN 60 751.The nominal value of Pt100 sensors is 100 at 0 °C. The temperature coefficient α can be stated simply to be between 0 °C and 100 °C with:
α = 3.85 ? 10-3 °C-1
The relationship between the temperature and the electri-cal resistance is characterised by polynomials which are defined in DIN EN 60 751. Furthermore, this standard lays down the basic values in °C stages
