RKC INSTRUMENT SBR-EW180, User Manual

Page: 198 / 234

11-5
IMSBR10-E1
Maintenance
11
Temperature Measurement When Using an RTD
Decade resisitance box
The resistance of three lead
wires must be equal.
Input terminal
+/A /b -/B
SBR-EW180
L
N
Temperature Measurement When Using a Thermocouple
Thermocouple wires or TC extension wires Copper wires
DC voltage standard
+
−
Input terminal
SBR-EW180
Thermocouple
wires
Copper
wires
(0
°
C standard temperature device)
+/A
−
/B
L
N
1
RJC of TC input
As the measurement terminal of the recorder is generally at room temperature, the actual output of the
thermocouple is different from the values given on the thermoelectromotive force table based on 0
° C. The
recorder performs compensation by measuring the temperature at the input terminal and adding the
corresponding thermoelectromotive force to the actual output of the thermocouple. Therefore, when the
measurement terminal is shorted (equivalent to the case when the detector tip is 0
° C), the measured value
indicates the temperature of the input terminal.
When calibrating the recorder, this compensation voltage (thermoelectromotive force of 0
° C reference
corresponding to the input terminal temperature) must be subtracted from the output of the DC voltage standard
before application. As shown in the figure, by using the 0
° C standard temperature device to compensate the
reference junction at 0 ° C, you can input the thermoelectromotive force of 0 ° C reference from the DC voltage
standard and perform the calibration.
11.4 Calibrating the Recorder