Specifications

Section 4. Sensor Support
4-23
each analog terminal strip measured the temperature of an insulated aluminum
bar outside the chamber. The temperature of this bar was also measured by
another datalogger. Differences between the temperature measured by one of
the thermocouples and the actual temperature of the bar are due to the
temperature difference between the terminals the thermocouple is connected to
and the thermistor reference (the figures have been corrected for thermistor
errors). FIGURE 4.4-2 shows the errors when the
chamber was changed from
-55 to 85°C in approximately 15 minutes. FIGURE 4.4-3 shows the results
whe
n going from 85 to 25°C. During these rapid changes in temperature, the
temperature of panel thermistor will tend to lag behind the terminals because it
is mounted deeper in the CR1000.
Reference Temperature Errors Due to Panel Gradient
Chamber Changed from - 55 to 85 degrees C
-2
0
2
4
6
8
10
12
135791113151719212325272931333537394143
Time Minutes
Measured - Actual degrees C
-60
-40
-20
0
20
40
60
80
Chamber and Reference Temperature degrees C
Channel 1
Channel 3
Channel 4
Channel 5
Channel 6
Channel 8
RefTemp_Avg
Chamber Temp
FIGURE 4.4-2. Panel Temperature Gradients during -55 to 80 °C Change