EN
WIKA operating instructions, model CTR3000
13
14191761.01 05/2019 EN/DE
4. Design and function
4.1.3 Thermocouple reference junction compensation
The electrical connection between the thermocouple element and the CTR3000 input connector is often referred to as
the internal reference junction. All standard thermocouple reference functions are defined relative to 0 °C. To eliminate the
physical need to reproduce this temperature inside the CTR3000, the actual connection temperature is accurately measured
with an internal PRT. This temperature is converted to an equivalent EMF and added to the actual thermocouple voltage
measurement, thereby correcting for the connection temperature.
For high-precision thermocouple measurement applications, i.e. calibration, an external reference junction may be used. Using
an external reference junction eliminates the uncertainties associated with reference junction compensation.
4.2 Front panel
1
Front end USB: Upload and download function, see chapter 6.5 “Download function”.
2
User interface and touchscreen, see chapter 4.5 “User interface, touchscreen”.
3
Power on/off, see chapter 6.3.1 “Key ON/OFF”.
4
Input for thermocouples (standard miniature plug), see chapter 4.3.2 “Thermocouples”.
5
Input for resistance thermometers or thermistors (5-DIN plug), see chapter 4.3.1 “Resistance thermometers”.
4.3 Thermometer inputs
The CTR3000 has two resistance thermometer and two thermocouple input channels, the input sockets are located on the
instruments front panel.
4.3.1 Resistance thermometers
PRTs are connected via the 5-pin DIN sockets as 3- or 4-wire.
Un-terminated platinum resistance thermometers may be connected through an optional adapter box or the universal
multiplexer CTS3000.
This is available as an accessory, see chapter 12 “Accessories”.
4
5
1
2
3
