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7 Applied Instructions (Program Flow)
7.4 IRET / Interrupt Return
117
FXCPU Structured Programming Manual
[Basic & Applied Instruction]
1
Outline
2
Instruction List
3
Configuration of
Instruction
4
How to Read
Explanation of
Instructions
5
Basic Instruction
6
Step Ladder
Instructions
7
Applied Instructions
(Program Flow)
8
Applied Instructions
(Move and
Compare)
9
Applied Instructions
(Arithmetic and
Logical Operation)
10
Applied Instructions
(Rotation and
Shift Operation)
7.4 IRET / Interrupt Return
Outline
This instruction returns the program execution from an interrupt routine to the main program.
1. Format and operation, execution form
2. Input and output data types
3. Applicable devices
Function and operation explanation
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 the three types of jump to an interrupt routine.
*1. This function is provided only in the FX
3U, FX3UC and FX2C PLCs Ver. 3.07 or later.
→ For the interrupt function, refer to Chapter 35.
FX3U(C) FX3G(C) FX3S FX2N(C) FX1N(C) FX1S FXU/FX2C FX0N FX0(S)
Instruction
name
Operation
Execution
form
Expression in each language
Structured ladder/FBD ST
IRET 16 bits Continuous IRET(EN);
Variable Description Data type
Input
variable
EN Execution condition Always TRUE
Output
variable
ENO Execution state Bit
Operand
type
Bit Devices Word Devices Others
System User Digit Specification
System
User
Special
Unit
Index
Constant
Real
Number
Character
String
Pointer
XYMTCS
D.b
KnX KnY KnM KnS T C D R
U\G
VZModifier K H E
""
P
- No target device is available.
Function Description
Input interrupt Executes the interrupt processing when an input(X) signal turns ON or OFF.
Timer interrupt Executes the interrupt processing at a specified time interval (constant cycle).
Counter interrupt
*1
Executes the interrupt processing when a high speed counter reaches its set value.
IRET
EN ENO