Mitsubishi Q00CPU User Manual

6
FUNCTIONS
6.2 Constant scan
6 - 5
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 using built-in Ethernet ports of CPU module
8
Communication with Intelligent Function Module
6.2 Constant scan
(1) Definition of Constant Scan
The scan time differs because the processing time differs depending on whether the
instruction, which is used in the sequence program, is executed or not.
Constant scan is a function to execute the sequence program repeatedly while
maintaining the scan time at a constant time.
(2) Applications of constant scan
I/O refresh is performed before sequence program execution.
Using the constant scan function, the I/O refresh intervals can be made constant if the
sequence program execution time varies.Note1
Note1
Scan time when constant scan is not used
Scan time when constant scan setting is set to 7 ms
Scan time when constant scan is set to 10 ms during multiple program execution
Note6.1
Figure 6.1 Constant scan operation
Basic
Note6.1
Since the Basic model QCPU cannot execute multiple programs, it is not necessary to be
conscious of the scan time taken for execution of multiple programs.
Basic
Note6.1
END
5ms
0 END 0
END 0 END 0
6ms
5ms
Sequence program
END processing
END
5ms
0
END
0
2ms 6ms
END
0
1ms
5ms
END
0
2ms
7ms7ms 7ms
Sequence program
END processing
Waiting time
8ms 2ms
10ms
9ms 1ms
10ms
Sequence program A
Sequence program B
Sequence program C
END processing
Waiting time

Mitsubishi Q00CPU Specifications

General

Brand	Mitsubishi
Model	Q00CPU
Category	Controller
Language	English