2. Thermocouple
Assembly Measuring Circuit (Schematic Diagram)
Figure 1 contains schematic diagrams with external / internal
reference junction
- With internal reference junction
a. Measuring point: Junction of the two different metals in the thermocouple
b. Thermocouple
c. Connection point: Junction between thermocouple and
compensating cable
d. Compensating cable: Has the same thermoelectric
properties as the thermocouple, up to 200°C
e. External reference junction:
At a constant temperature (e.g. 0°C or 50°C)
f. Copper cable: Connection
cable between the external reference junction and the measuring instrument.
g. Adjustable resistor (is only required for measurement equipment with
low-impedance input, such as moving coil indicators without amplifiers)
h.
Measuring instrument for measuring circuits with external reference junctions
(e.g. controller or slider)
i. Measuring equipment with internal reference
junction, such as:
• controllers whose clamp
temperature is measured internally and then converted to an auxiliary voltage,
which standardizes the thermocouple assembly
signal.
• Transmitter (mV or 0/4-20mA) with
downstream instrument (e.g. controller)
Go to
Section 3 (Configuration of
Thermocouple Assemblies)
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