RoboteQ AX2550 Computer Hardware User Manual


 
AX1500 Motor Controller Users Manual 61
Connecting External Thermistor to Analog Inputs
Connecting External Thermistor to Analog Inputs
Using external thermistors, the AX1500 can be made to supervise the motors tempera-
ture and adjust the power output in case of overheating. Connecting thermistors is done
according to the diagram show in Figure 30. The AX1500 is calibrated using a 10kOhm
Negative Coefficient Thermistor (NTC) with the temperature/resistance characteristics
shown in the table below.
Thermistors are non-linear devices. Using the circuit described on Figure 30, the controller
will read the following values (represented in signed binary) according to the temperature.
TABLE 11. Recommended NTC characteristics
Temp (oC) -25 0 25 50 75 100
Resistance (kOhm) 86.39 27.28 10.00 4.16 1.92 0.93
47kOhm
10kOhm
47kOhm
10kOhm
10kOhm
NTC
Thermistor
Internal Resistors
and Converter
+5V 14
Ground 5
A/D
Ana 1: 11
Ana 2: 10
Ana 3: 12
Ana 4: 8
FIGURE 30. NTC Thermistor wiring diagram