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16
4.6 Temperature Measurement
The 8020-59 is capable of reading the thermistor that is part of a VW sensor. The 8020-59
outputs this reading as a voltage (0-5V) and current (4-20mA) that are proportional to
temperature whenever ENABLE is high (5V), in Single Channel Mode, or while the second
clock pulse is high, in 16-Channel mode. See Figure 14 for 16-Channel mode control signal
timing.
Temperature is derived from the voltage output by Equation 6.
Note: Assumes Vout is in volts (V). Minimum Temperature = -20 °C, Degree Span = 100°.
°C = Minimum Temperature + (Vout * (Degree Span / 5V)) =
-20° + (20 * Vout)
Equation 6 - Temperature Derived from Voltage Output
Temperature is derived from the current output by Equation 7.
Note: Assumes Iout is in milliamperes (mA).
° C = Minimum Temperature + ((Iout - 4mA) * (Degree Span / 16mA)) =
-20° + (6.25 * (Iout - 4mA))
Equation 7 - Temperature Derived from Current Output
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