Mitsubishi Q00JCPU User Manual page 505

6
FUNCTIONS
(3) Program memory check execution
(a) Process CPU and Redundant CPU
(b) Universal model QCPU
(4) Device memory: At device readProcessing time of memory check
(a) Process CPU and Redundant CPU
(b) Universal model QCPU
Memory check is executed both at "STOP to RUN switching" and "END
processing" during RUN.
• At STOP to RUN switching:Checks all area of the program memory.
• At END processing
The program memory, device memory, and parameters are checked automatically
at the timing below.
1) Program memory
a) Programs: At program execution
b) Parameters:
• At power OFF to ON
• At reset clear
• At STOP to RUN after Write to PLC
1) At STOP to RUN switching
When memory check is executed, STOP to RUN switching delays by the
processing time of memory check shown below.
• Q12PHCPU, Q12PRHCPU:434 ms
• Q25PHCPU, Q25PRHCPU:882 ms
2) At END processing during RUN
If a program memory is checked, the scan time takes longer.
In "PLC RAS(2)" tab in Qn(H) Parameter the dialog box, set the capacity to be
checked at one time in consideration of the increase in scan time.
Calculate increases in scan time by the following expression.
(Increases in scan time) = 3.5
For example, when setting a check capacity 4 in "PLC RAS(2)" tab in Qn(H)
Parameter the dialog box at one time, the processing time will be
3.5 4 256 1024=3.5(ms).
* 1 : Indicates "Capacity to be checked at one time" set in "PLC RAS(2)" tab in the dialog box Qn(H)
Parameter. ( (2) in this section)
It takes no processing time for memory check.
:Checks by the capacity set at "Capacity to be
checked at one time
RAS(2) tab of the PLC parameter dialog box.
(Capacities to be checked at one time)* X 256
X
1024
6.28 Memory Check Function
256 step" in the PLC
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(ms)
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