Mitsubishi FX1S Series

FX Series Programmable Controllers Devices in Detail 4
4-11
4.6 Interrupt Pointers
Device Mnemonic: I
Purpose: Interrupt program marker
Alias: Interrupt
High speed interrupt
I
Available forms: Label: appears on the left of the left hand bus bar when the program is
viewed in ladder mode
(see À in the example device usage diagram).
Devices numbered in: Special numbering system based on interrupt device used and input
triggering method
Further uses: Input interrupts - see page 4-12
Timer interrupts - see page 4-12
Disabling interrupts - see page 4-13
Counter interrupts - see page 4-13
Example device usage:
Additional applied instructions:
• Interrupts are made up of an interrupt device, an interrupt pointer and various usage of
three, dedicated interrupt applied instructions;
- IRET function 03: interrupt return
- EI function 04: enable interrupt
- DI function 05: disable interrupt
Nested levels:
• While an interrupt is processing all other interrupts are disabled. To achieve nested
interrupts the EI-DI instruction must be programmed within an interrupt routine.
Interrupts can be nested for two levels.
Pointer position:
• Interrupt pointers may only be used after an FEND instruction (first end instruction,
function 06).
FX 1S
FX1N FX2N
FX2NC
I101
IRET
FEND
1
END