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FX3S/FX3G/FX3GC/FX3U/FX3UC Series
Programming Manual - Basic & Applied Instruction Edition
8 Program Flow – FNC 00 to FNC 09
8.4 FNC 03 – IRET / Interrupt Return
1
Introduction
2
Overview
3
Instruction
List
4
Devices
in Detail
5
Specified the
Device &
Constant
6
Before
Programming
7
Basic
Instruction
8
FNC00-FNC09
Program Flow
9
FNC10-FNC19
Move & Compare
10
FNC20-FNC29
Arith. & Logic
Operation
8.4 FNC 03 – IRET / Interrupt Return
Outline
This instruction returns the program execution from an interrupt routine to the main program.
1. Instruction format
2. Set data
3. Applicable devices
Explanation of function and operation
When an interrupt (input, timer or counter) is generated while the main program is executed, the program execution
jumps to an interrupt (I) routine.
IRET instruction returns the program execution to the main routine.
The table below shows three types of jump to an interrupt routine.
1. Types of interrupt function
*1. This function is supported only in FX3U/FX3UC PLCs.
→ For the interrupt function, refer to Chapter 36.
Operand type Description Data type
– There is no set data. –
Oper-
and
Type
Bit Devices Word Devices Others
System User Digit Specification System User
Special
Unit
Index
Con-
stant
Real
Number
Charac-
ter String
Pointer
XYMTCSD.b KnX KnY KnM KnS T C D R U\G V Z Modify K H E ""P
– There are no applicable devices.
Function Interrupt No. Description Reference
Input interrupt I00* to I50*
Executes the interrupt processing when an input (X) signal turns ON or
OFF.
Section 36.3 and
Section 36.4
Timer interrupt I6** to I8**
Executes the interrupt processing at a specified time interval (constant
cycle).
Section 36.5
Counter interrupt
*1
I010 to I060
Executes the interrupt processing when a high-speed counter reaches
it’s set value.
Section 36.6
FNC 03
IRET
IRET
Mnemonic Operation Condition
Continuous
Operation
Independent Inst.
1 step
This instruction is the independent type, and
does not require drive contact.