User`s manual

10 - 5
10.1 Scan Time
10.1.3 Factors that increase the scan time
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CPU MODULE PROCESSING TIME
10.1.3 Factors that increase the scan time
When the following functions or operations are performed, this will increase the scan time
of the CPU module.
When executing any of them, make sure to allow for the processing time (the value given
in this section to the value calculated in Section 10.1.2).
(1) Online change executed in ladder mode
The scan time increases by the value indicated in Table10.5 after online change.
(2) Functions that increase scan time
The scan time also increases by use of the following functions.
• System monitor
• General data processing
(3) Salf-diagnostics executed in certain cycle
The CPU module has the salf-diagnostics processing in a certain cycle (10ms)
regardless of the scan.
Therfore, scan time changes due to processing time for salf-dingnostics processing in
a certain cycle.
When scan time calculated from calculating formula in Section 10.1.1 is 15ms,
change of scan time due to sale-diagnostics processing in a certain cycle is shown in
Diagram 10.2.
Table10.5 Increased time when online change is in ladder mode
CPU module model name
Allocate memory for online change
No change Re-setting
QS001CPU Max. 1.7ms Max. 36ms
Table10.6 Processing time for salf-diagnostics in a certain cycle
CPU module model name Processing time
QS001CPU 0.2 to 3.0ms