Campbell CR800 Especificações descarregar pdf (Página 84)

Section 3. CR800 Measurement Details

3-10

Panel Temperature error summary

-0.1

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

-55 -35 -15 5 25 45 65 85

Sum of Worst Case Errors

Thermistor Tolorance

CR1000 Measurement

Completion Resistor Error

S&H Err

FIGURE 3.4-1. Panel Temperature Errors

With an external driving gradient, the temperature gradients on the input panel

can be much worse. For example, the CR800 was placed in a controlled

temperature chamber. Thermocouples in channels at the ends and middle of

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 3.4-2 shows the errors when the chamber was changed from

-55° to 85°C in approximately 15 minutes. Figure 3.4-3 shows the results

when 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 buried a bit deeper in the CR800.

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Campbell CR800 Especificações Página 84