AC 80000;DC 80000
Acceleration
#Loop
VP=@AN[1]*1000
Read analog input and compute position
PA VP
Command position
BGX Start
motion
AMX After
completion
JP #Loop
Repeat
EN End
Example - Position Follower (Continuous Move)
Method: Read the analog input, compute the commanded position and the position error.
Command the motor to run at a speed in proportions to the position error.
Instruction Interpretation
#Cont Label
AC 80000;DC 80000
Acceleration rate
JG 0
Start job mode
BGX Start
motion
#Loop
VP=@AN[1]*1000
Compute desired position
VE=VP-_TPX
Find position error
VEL=VE*20 Compute
velocity
JG VEL
Change velocity
JP #Loop
Change velocity
EN End
Example Applications
Wire Cutter
An operator activates a start switch. This causes a motor to advance the wire a distance of 10".
When the motion stops, the controller generates an output signal which activates the cutter.
Allowing 100 ms for the cutting completes the cycle.
Suppose that the motor drives the wire by a roller with a 2" diameter. Also assume that the
encoder resolution is 1000 lines per revolution. Since the circumference of the roller equals 2
π
inches, and it corresponds to 4000 quadrature, one inch of travel equals:
4000/2
π
= 637 count/inch
This implies that a distance of 10 inches equals 6370 counts, and a slew speed of 5 inches per
second, for example, equals 3185 count/sec.
The input signal may be applied to I1, for example, and the output signal is chosen as output 1.
The motor velocity profile and the related input and output signals are shown in Fig. 7.1.
The program starts at a state that we define as #A. Here the controller waits for the input pulse on
I1. As soon as the pulse is given, the controller starts the forward motion.
Upon completion of the forward move, the controller outputs a pulse for 20 ms and then waits an
additional 80 ms before returning to #A for a new cycle.
Instruction Function
152
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Chapter 7 Application Programming
DMC-1600
