Chapter 5 Temperature Controller Operation 61
Figure 31 - Thermistor Temperature Range
5.4.4.1.3 Temperature Resolution
You must also consider measurement resolution since the resolution decreases as the
thermistor temperature increases. The 6000 uses an A/D converter that has a
maximum resolution of about 76 µV. The microprocessor converts this digital
number to resistance, stores this resistance, then converts it to a temperature using the
Steinhart-Hart equation, and stores this temperature. A temperature change of one
degree centigrade will be represented by a greater resistance increase (and therefore
more A/D counts) at a lower temperature than at a higher temperature because of the
non-linear resistance of the thermistor. Resolution figures for a typical 10 k Ohm
thermistor are given below.
To Next Page
Loading...
