Galil Motion Control DMC-18 2 Series, User Manual, Page: 154 / 218

DMC-18x2 Chapter 7 Application Programming • 143
Input Interrupt Function
The DMC-18x2 provides an input interrupt function which causes the program to automatically
execute the instructions following the #ININT label. This function is enabled using the II m,n,o
command. The m specifies the beginning input and n specifies the final input in the range. The
parameter o is an interrupt mask. If m and n are unused, o contains a number with the mask. A 1
designates that input to be enabled for an interrupt, where 20 is bit 1, 21 is bit 2 and so on. For
example, II,,5 enables inputs 1 and 3 (20 + 22 = 5).
A low input on any of the specified inputs will cause automatic execution of the #ININT subroutine.
The Return from Interrupt (RI) command is used to return from this subroutine to the place in the
program where the interrupt had occurred. If it is desired to return to somewhere else in the program
after the execution of the #ININT subroutine, the Zero Stack (ZS) command is used followed by
unconditional jump statements.
IMPORTANT: Use the RI instruction (not EN) to return from the #ININT subroutine.
Examples - Input Interrupt
#A Label #A
II 1 Enable input 1 for interrupt function
JG 30000,-20000 Set speeds on X and Y axes
BG XY Begin motion on X and Y axes
#B Label #B
TP XY Report X and Y axes positions
WT 1000 Wait 1000 milliseconds
JP #B Jump to #B
EN End of program
#ININT Interrupt subroutine
MG "Interrupt has
occurred" Displays the message
ST XY Stops motion on X and Y axes
#LOOP;JP
#LOOP,@IN[1]=0
Loop until Interrupt cleared
JG 15000,10000 Specify new speeds
WT 300 Wait 300 milliseconds
BG XY Begin motion on X and Y axes
RI Return from Interrupt subroutine
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
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