
11. INTERRUPT–TYPE
PMC FUNCTION
B–61863E/15
PMC SEQUENCE PROGRAM
406
Input/output signals (F, G, X, Y addresses) between the NC and machine
are processed asynchronously except for built–in I/O units (X1000 to
X1003, X1007, Y1000 to Y1002). (Usually, processing for NC <–> PMC
(F/G), Link master (X0 to X127), and I/O Link slave (X1020 to X1051,
Y1020 to Y1051) is performed at 8–, 2–, or 8–ms intervals, respectively.)
When an interrupt–type PMC is used, input signals (X1000 to X1003,
X1007) from a built–in I/O unit are read immediately before the interrupt
program is executed. Output signals (Y1000 to Y1002) to a built–in I/O
unit are written immediately after the interrupt program is executed.
Built–in I/O signals are processed at 8–ms intervals even when the
interrupt program is not executed.
The same signal is read from both X1007 and X1003, but signal changes
in X1007 can be read faster. Therefore, ladder programs should use
X1007 rather than X1003 when referencing an input signal.
To enable the interrupt program to judge interrupt input trigger
conditions, the interrupt request status (which of the signals defined by
bit 0 to bit 7 of X1003 causes the interrupt) is output to an internal relay
(R9021).
D Interrupt relay R9021 (interrupt request status)
#7
R9021
#6 #5 #4 #3 #2 #1 #0
This relay indicates the status of an interrupt request corresponding to
each interrupt input signal (bit 0 to bit 7 of X1003).
When a bit is set to 1, it indicates that the corresponding signal is
requesting an interrupt.
The interrupt program is executed within 0.5 ms (software response time)
after an interrupt input signal is received. If there is an interrupt–inhibited
interval, the execution of the interrupt program is deferred by the
corresponding time. If another interrupt input signal is received when the
interrupt program is already running, the newly received signal is kept
waiting until the current execution ends.
11.3.2
Input/Output Signal
Processing
11.3.3
Response Time