Yaskawa LEGEND-MC - Manual (Page 349)

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LEGEND-MC User’s Manual
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 Function
#A Label
AI1 Wait for input 1
PR 6370 Distance
SP 3185 Speed
BGX Start Motion
AMX After motion is complete
SB1 Set output bit 1
WT 20 Wait 20 ms
CB1 Clear output bit 1
WT 80 Wait 80 ms
JP #A Repeat the process
START PULSE I1
MOTOR VELOCITY
OUTPUT PULSE
TIME INTERVALS
move
output
wait ready move
Motor Velocity and the Associated Input/Output signals