Fnc 03 - Iret / Interrupt Return - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
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
FNC 03
IRET
2. Set data
Operand type
–
3. Applicable devices
Bit Devices
Oper-
and System User
Type
X Y M T C S D .b KnX KnY KnM KnS T C D R U \G
–
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
Function
Input interrupt
Timer interrupt
Counter interrupt
*1. This function is supported only in FX
240
Mnemonic
Independent Inst.
1 step IRET
There is no set data.
Digit Specification
Interrupt No.
Executes the interrupt processing when an input (X) signal turns
I00* to I50*
ON or OFF.
Executes the interrupt processing at a specified time interval
I6** to I8**
(constant cycle).
Executes the interrupt processing when a high speed counter
*1
I010 to I060
reaches it's set value.
Operation Condition
This instruction is the independent type, and
Continuous
does not require drive contact.
Operation
Description
Word Devices
Special
System User
Unit
There are no applicable devices.
Description
/FX PLCs.
3U 3UC
→ For the interrupt function, refer to Chapter 36.
8 Program Flow – FNC 00 to FNC 09
8.4 FNC 03 – IRET / Interrupt Return
Others
Con- Real
Index
stant Number
V Z Modify K H E
Data type
–
Charac-
Pointer
ter String
" " P
Reference
Section 36.3
and
Section 36.4
Section 36.5
Section 36.6