Iret, Ei, Di(Fnc 03, 04, 05) - Mitsubishi FX1S Series Programming Manual

FX Series Programmable Controlers
5.1.4 IRET, EI, DI
(FNC 03, 04, 05)
Mnemonic
IRET
FNC 03
(Interrupt
return)
EI
FNC 04
(Enable
interrupts)
DI
FNC 05
(Disable
interrupts)
I
(Interrupt
pointer)
General description of an interrupt routine:
An interrupt routine is a section of program which is, when triggered, operated immediately
interrupting the main program flow. Once the interrupt has been processed the main program
flow continues from where it was, just before the interrupt originally occurred.
Operation:
Interrupts are triggered by different input conditions, sometimes a direct input such as X0 is
used other times a timed interval e.g. 30 msec can be used. The availability of different
interrupt types and the number operational points for each PLC type are detailed on page 4-
12, Interrupt Pointers. To program and operate interrupt routines requires up to 3 dedicated
instructions (those detailed in this section) and an interrupt pointer.
Defining an interrupt routine:
An interrupt routine is specified between its own
unique interrupt pointer and the first occurrence of an
IRET instruction.
Interrupt routines are ALWAYS programmed after an
FEND instruction.
The IRET instruction may only be used within
interrupt routines.
Function
Forces the N/A
program to return Automatically returns to the main program step
from the active which was being processed at the time of the
interrupt routine interrupt call.
Enables interrupt N/A
inputs to be pro- Any interrupt input being activated after an EI
cessed instruction and before FEND or DI instructions
will be processed immediately unless it has
been specifically disabled.
Disables the N/A
processing of Any interrupt input being activated after a DI
interrupt routines instruction and before an EI instruction will be
stored until the next sequential EI instruction is
processed.
Identifies the A 3 digit numeric code relating to the interrupt
beginning of an type and operation.
interrupt routine
FX
1S
Operands
D
Applied Instructions 5
FX FX FX
1N 2N 2NC
Program steps
IRET:
1 step
EI:
1 step
DI:
1 step
PPP
I :
1 step
5-10