RoboteQ AX2850 - Manual (Page 125)

AX2550 Motor Controller User’s Manual 125
Connecting to a Voltage Source
Connecting to a Voltage Source
The analog inputs expect a DC voltage of 0 to 5V which can be sourced by any custom cir-
cuitry (potentiometer, Digital to Analog converter).
The controller considers 2.5V to be the zero position (Motor Off). 0V is the maximum
reverse command and +5V is the maximum forward command.
The inputs’ equivalent circuit is show in Figure 83 below.
Notice the two 47K resistors, which are designed to automatically bring the input to a mid-
point (Off) position in case the input is not connected. The applied voltage must have suffi-
cient current (low impedance) so that it is not affected by these resistors.
Connecting a Potentiometer
Figure 84 shows how to wire a potentiometer to the AX2550. By connecting one end to
ground and the other to 5V, the potentiometer acts as an adjustable voltage divider. The
voltage will thus vary from 0V when the tap is at the minimum position and to 5V when the
tap is at the maximum position.
The controller considers 2.5V to be the zero position (Motor Off). 2.5V is the potentiome-
ter’s mid point position.
47kOhm
10kOhm
47kOhm
Internal Resistors
and Converter
Analog
In1: pin 11
In2: pin 10
0V = Min
2.5V = Off
5V = Max
+5V 14
13
Ground
A/D
FIGURE 83. Analog input circuit