3
SEQUENCE PROGRAM CONFIGURATION AND
EXECUTION CONDITIONS
3.3 Settings for Creation and Execution of Multiple Sequence Programs
3.3.5 Fixed scan execution type program
3
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1
Overview
2
Performance
Specification
3
Sequence Program
Configuration and
Execution Conditions
4
I/O Nunber Assignment
5
Memories and Files
Handled by CPU Module
6
Functions
7
Communication with
Intelligent Function
Module
8
Parameters
3.3.5 Fixed scan execution type program
(1) Definition of fixed scan execution type programNote23
This program is executed at the specified time intervals.
It can be executed at fixed cycle intervals for each file without description of interrupt
pointers and IRET instructions.
(2) Fixed scan execution type program processing
Fixed scan execution type program processing is explained below.
(a) When there are multiple fixed scan execution type programs
Fixed scan execution type programs are executed at the specified time intervals.
When multiple fixed scan execution type programs reach the specified time at the
same time, they are executed in ascending order of the numbers set in the
program setting of the PLC parameter dialog box. ( (4) in this section)
(b) When there are fixed scan execution type program and interrupt program
When the fixed scan execution type program and an interrupt program (I28 to 31)
reach the specified time at the same time, the interrupt program is executed first
with priority.
(c) Execution during network refresh
When the execution condition for the fixed scan execution type program is
satisfied during network refresh, network refresh is suspended and the fixed scan
execution type program is executed.
Even if the cyclic data block has been guaranteed for each station in the
MELSECNET/H network system, it is not available when the device set as a
network refresh target is used in the fixed scan execution type program.
In the fixed scan execution type program, do not use the device set as a network
refresh target.
Note23
Diagram 3.43 Execution of fixed scan execution type program
Basic
Note3.23
The fixed scan execution type program is not available for the Basic QCPU.
Note3.23
Basic
Fixed scan interval
END processing
Fixed scan execution
type program
Scan execution
type program
Condition
enabled
Condition
enabled