Subroutines And Interrupt Control; Exclusive Nor - Xnrw(37); Overview - Omron SYSMAC C2000H Operation Manual

Subroutines and Interrupt Control

5-19-5 EXCLUSIVE NOR – XNRW(37)
Description
I1
I2
R
Flags
5-20

Subroutines and Interrupt Control

5-20-1

Overview

182
Ladder Symbols
XNRW(37) @XNRW(37)
I1
I2
R
When the execution condition is OFF, XNRW(37) is not executed. When the
execution condition is ON, XNRW(37) exclusively NOR's the contents of I1
and I2 bit-by-bit and places the result in R.
15
1 0 0 1 1 0 0
15
0 1 0 1 0 1 0
15
0 0 1 1 0 0 1
Indirectly addressed DM word is non-existent. (Content of *DM word
ER:
is not BCD, or the DM area boundary has been exceeded.)
EQ: ON when the result is 0.
Subroutines break large control tasks into smaller ones and enable you to
reuse a given set of instructions. When the main program calls a subroutine,
control is transferred to the subroutine and the subroutine instructions are
executed. The instructions within a subroutine are written in the same way as
main program code. When all the subroutine instructions have been exe-
cuted, control returns to the main program to the point just after the point
from which the subroutine was entered (unless otherwise specified in the
subroutine).
Subroutines may also be activated by interrupts. Like subroutine calls, inter-
rupts cause a break in the flow of the main program execution such that the
flow can be resumed from that point after completion of the subroutine. An
interrupt is caused either by an external source, such as an input signal from
an Interrupt Input Unit, or a scheduled interrupt. In the case of the scheduled
interrupt, the interrupt signal is repeated at regular intervals.
Whereas subroutine calls are controlled from within the main program, sub-
routines activated by interrupts are triggered when the interrupt signal is re-
ceived. Also, multiple interrupts from different Interrupt Input Units can occur
IR, SR, AR, DM, HR, TC, LR, #
I1
IR, SR, AR, DM, HR, TC, LR, #
I2
R
1 1 0 0 1 1 0
1 0 1 0 1 0 1
1 0 0 1 1 0 0
Section 5-20
Operand Data Areas
I1: Input 1
I2: Input 2
R: Result word
IR, AR, DM, HR, LR
00
0 1
00
0 1
00
1 1