Allen-Bradley 2080-LC20-20QWB User Manual page 52

Chapter 4 Wire Your Controller
44
Analog input to thermistors
Thermistor 3
Thermistor 2
Thermistor 1
Thermistor 0
Note: Terminal block to wire
commons is not included in
Micro800 package.
The "+DC10" terminal supplies 10V DC power source to the Thermistor inputs (I-00 to I-03).
Calculate for Thermistor Resistance
While connecting Analog input to thermistor as shown in previous diagram,
calculate input voltage using the following equation:
Ri
Vi =
Ri + Rt
Where:
Vi = Voltage input (±5% without calibration; ±2% with calibration)
Ri = Resistance input (14.14 KΩ ±2%)
Rt = Thermistor resistance (10 KΩ Thermistor is recommended)
Vref = 10V ±0.5V
To calculate for thermistor resistance, use the following equation.
Vi Vref - Vi Ri
Rt=
Vi
Micro820 controllers support 10 KΩ type thermistors.
IMPORTANT
In order to get the best results, the system must be calibrated.
1 2 3 4
1 2 3 4
+DC10 I-00 I-02 COM0
1 2 3 4 5 6 7 8
-DC24 I-01 I-03 I-04
* Vref
Rockwell Automation Publication 2080-UM005B-EN-E - March 2015
46255
I-05 I-07 I-09 I-11
9 10 11 12 13 14 15 16
I-06 I-08 I-10 NU