Campbell CR23X, Operator'S Manual

Page: 215 / 374

SECTION 13. CR23X MEASUREMENTS
13-15
100K6A1 Interchangeability Error (deg C)
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
-40 -30 -20 -10 0 10 20 25 30 40 50 60 70 80
Temperature
Error (deg C)
FIGURE 13.4-1. BetaTherm 100K6A1 Interchangeability Error
When the CR23X is subjected to large
temperature gradients or rapid temperature
changes, The reference temperature error can
be much greater. Figure 13.4-2 shows the
errors on three different channels while the
CR23X was in a chamber that had the
temperature changed from -40 to +60°C in
about 12 minutes. The initial error while the
temperature is stable at -40°C (-10 to 0
minutes) is largely thermistor interchangeablity
error. During the temperature change, the differences in temperature between the input
terminals and the reference thermistor
dominate the error. Wire routing, the battery
base, and the source of the temperature
gradient can affect which channels have the
greatest error. When making thermocouple
measurements, ALWAYS USE THE
TERMINAL COVER; the above test without the
cover results in errors more than three times
worse than shown in Figure 13.4-2.