Campbell Scientific CR10XTCR Thermocouple Reference - Manual (Page 5)

1
CR10XTCR Thermocouple Reference
1. General
The Model CR10XTCR Probe contains a thermistor for measuring temperature
and is used as a reference temperature for thermocouples measured with the
CR10X. It is installed between the two terminal stripes in the wiring panel.
After all the thermocouples are wired, the wiring panel cover is installed to
minimize temperature gradients on the terminal strip.
1.1 Specifications
Temperature Measurement Range: -35
° to +50°C
Thermistor Interchangeability Error: Typically <
±0.2°C over 0°C to 60°C ±0.4
@ -35
°C.
Polynomial Linearization Error: <
±0.5°C over -35°C to +50°C.
2. Accuracy — Temperature Sensor
The overall probe accuracy is a combination of the thermistor's
interchangeability specification, the precision of the bridge resistors, and the
polynomial error. In a "worst case" all errors add to an accuracy of
± 0.4
°C
over the range of -24
° to 48°C and ±0.9°C over the range of -38°C to 53°C.
The major error component is the interchangeability specification of the
thermistor, tabulated in Table 1. For the range of 0
° to 50°C the
interchangeability error is predominantly offset. The bridge resistors are 0.1%
tolerance with a 10 ppm temperature coefficient. Polynomial errors are
tabulated in Table 2 and plotted in Figure 1.
TABLE 1. Thermistor Interchangeability
Specification
Temperature (
°C)
Temperature
Tolerance (
±°C)
−40
0.40
−30
0.40
−20
0.32
−10
0.25
0 to +50 0.20
TABLE 2. Polynomial Error
-40 to +56 <
±1.0°C
-38 to +53 <
±0.5°C
-24 to +48 <
±0.1°C