Horner APG SmartStack I/O HE-THM100 - Manual (Page 4)

PAGE 4 10 NOV 2006 MAN0237-09
THM000/100
This Data Sheet is published individually & also as a part of the SmartStack Supplement (SUP0246-05).
Information is subject to change without notice. SmartStack is a trademark of Horner APG, LLC.
4 INPUT AND OUTPUT CONVERSIONS
For a given module configuration, use the appropriate formula in the table to obtain the actual
temperature (
°C or °F) that is represented by the value in the %AI register.
Temperature Conversion Thermocouple
Configuration
Celsius Fahrenheit
0.05
° °C = %AI / 20 * °F = %AI / 20 *
0.1
° °C = %AI / 10 ** °F = %AI / 10 **
0.5
° °C = %AI / 2 °F = %AI / 2
* Maximum reading in 0.05
°F or 0.05°C format is limited to 1638.3 because of %AI
resolution.
** Maximum reading in 0.1
°F or 0.1°C format is limited to 3276.7 because of %AI
resolution.
The following table describes how real-world inputs are scaled into the controller. Given a known input
voltage, the data value is configured by using the conversion factor from the table. The following formula
is used: Data = Voltage In (Vin) / Conversion Factor
Example: The user selects a voltage of 25mV.
1) The known input voltage is 25mV.
2) Using the table, the conversion factor for the voltage range of
± 25mV is 0.00078125.
3) To determine the data value, the formula is used:
Data = Vin / Conversion Factor
32000 = 25mV / 0.00078125
Conversion of Real-World Inputs to the Controller
%AI Value
Selected
Voltage Range
Voltage In
(Vin) VDC
Data Out Conversion
Factor
-25mv -32000
0 0
± 25mv
+25mv +32000
0.00078125
-50mv -32000
0 0
± 50mv
+50mv +32000
0.0015625
-100mv -32000
0 0
± 100mv
+100mv +32000
0.003125