Yaskawa LEGEND-MC - Manual (Page 348)

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LEGEND-MC User’s Manual
The following is the special label to handle input interrupts. Inputs 1 - 8 can be used as interrupts. this
example uses the input to tell the LEGEND that the system is under an E-STOP condition. This input may
come from a contact that also removes power from the amplifiers. Notice that the interrupt command II is
used at the beginning of the program to designate input #3 as an interrupt. When this input goes low,
thread zero automatically jumps to #ININT if it is included in the program. Notice that if the example
assumes that if an E-STOP occurs, the current operation has been scrapped. The ZS (Zero Subroutine
Stack) command is used which allows the program to jump anywhere. Usually it is easiest to jump back to
a main loop which handles the different modes of operation of the machine. Also note that if ZS is used,
the interrupt must be enabled for next time.
Wire Cutter
Activate the start switch. The motor will advance the wire a distance of 10". When motion stops, the
controller generates an output signal activating the cutter. Allow 100 ms for cutting to complete the cycle.
Suppose the motor drives the wire by a roller with a 2" diameter and 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
A distance of 10 inches equals 6370 counts, and a slew speed of 5 inches / second equals 3185 count/sec.
The input signal may be applied to I1, and the output signal as output 1. Motor velocity profile and related
input and output signals are in the following illustration -
Motor Velocity and Associated Input/Output signals .
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 Interpretation
#ININT
AB1; HX1; HX2; HX3
SB3
MG “ESTOPPED”
AI-3; AI3 (Wait for e-stop input to go high
(re-enabled))
CB3
MG “RE-ENABLED..”
SHX
WT2000
ZS
II3 (Re-enable input interrupt for next
time)
JP #BUSY
EN