6
FUNCTIONS
6.2 Constant scan
6 - 7
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
(a) Setting time condition
As the constant scan time, set a value that satisfies the following relational
expression.
If the sequence program scan time is longer than the constant scan setting time,
the CPU module detects PRG. TIME OVER (error code: 5010).
In this case, the constant scan setting is ignored and the sequence program is
executed based on its scan time.
If the sequence program scan time is longer than the WDT setting time, the CPU
module detects a WDT error.
In this case, the program execution is stopped.
(WDT Set Time) > (Constant Scan Set Time)
> (Sequence Program maximum Scan Time)
Figure 6.3 Operation when the Scan Time is longer than the Constant Scan
0
1 2
3
4 1 2
3
4
00
1
END 0END
2
3
4 1 2
3
4
0END 0END
3.5ms 0.5ms
4ms 4ms
3.5ms 3.4ms 0.6ms
4ms
5.3ms
5
ms
0.5ms
Scan where the constant scan is not normal
Constant scan setting
Constant
scan
Sequence
program
(Setting time: 4ms)