5.10 Interrupt Instructions; Interrupt Routine, Return From Interrupt Routine; Enable Interrupt, Disable Interrupt - Siemens Simatic S7-200 CPU 210 System Manual

Instruction Set

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

L
A
D
S
INT
T
L
RETI
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

L
A
D
S
ENI
T
L
DISI
5-14
The Interrupt Routine instruction marks the beginning of the
0
interrupt routine.
INT
The Unconditional Return from Interrupt coil must be used to
terminate the interrupt routine.
RETI
Operands:
0
The Enable Interrupt instruction enables processing of the
interrupt events.
ENI
The Disable Interrupt instruction globally disables processing
of the interrupt events. While interrupts are disabled, interrupt
DISI
events are ignored.
Operands:
n: 0
None
S7-200 Programmable Controller, CPU 210
C79000-G7076-C235-01