DMC-1000 Chapter 7 Application Programming • 121
R=2
BC
A
0 4 9.3
4
Y
X
Figure 7.2 - Motor Velocity and the Associated input/output signals
Speed Control by Joystick
The speed of a motor is controlled by a joystick. The joystick produces a signal in the range between -
10V and +10V. The objective is to drive the motor at a speed proportional to the input voltage.
Assume that a full voltage of 10 Volts must produce a motor speed of 3000 rpm with an encoder
resolution of 1000 lines or 4000 count/rev. This speed equals:
3000 rpm = 50 rev/sec = 200000 count/sec
The program reads the input voltage periodically and assigns its value to the variable VIN. To get a
speed of 200,000 ct/sec for 10 volts, we select the speed as
Speed = 20000 x VIN
The corresponding velocity for the motor is assigned to the VEL variable.
Instruction Interpretation
#A Label
JG0 Set jog speed of zero
BGX Begin jogging (at speed zero)
#B Label
VIN=@AN[1] Set variable, VIN, to value of analog input 1
VEL=VIN*20000 Set variable, VEL to multiple of variable of VIN
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