Siemens Simatic S7-200 CPU 210, System Manual

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5-14
S7-200 Programmable Controller, CPU 210
C79000-G7076-C235-01
5.10 Interrupt Instructions
The CPU 210 has one interrupt event (rising edge of
I0.0
). To access this event, you must
program an interrupt routine (INT 0), and enable the interrupt. The ENI (enable interrupt)
instruction must be executed. An interrupt will occur on the next rising edge of
I0.0
(after
the ENI instruction is executed). It is only necessary to execute the ENI instruction once
each time the CPU 210 is powered up unless the DISI (disable interrupt) instruction is
executed.
Interrupt Routine, Return from Interrupt Routine
The Interrupt Routine instruction marks the beginning of the
interrupt routine.
The Unconditional Return from Interrupt coil must be used to
terminate the interrupt routine.
Operands: n: 0
You can identify the interrupt routine by the interrupt routine label that marks the entry point
into the routine. The routine consists of all your instructions between the interrupt label and
the unconditional return from interrupt instruction. The interrupt routine executes in response
to the rising edge of
I0.0
. You must end the routine (thereby returning control to the main
program) by executing the Return from Interrupt instruction (RETI).
Enable Interrupt, Disable Interrupt
The Enable Interrupt instruction enables processing of the
interrupt events.
The Disable Interrupt instruction globally disables processing
of the interrupt events. While interrupts are disabled, interrupt
events are ignored.
Operands: None
Instruction Set
L
A
D
S
T
L
INT 0
RETI
INT
0
RETI
L
A
D
S
T
L
ENI
ENI
DISI
DISI