6
FUNCTIONS
6.28 Memory Check Function
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6.28 Memory Check Function
The memory check function checks whether the memory contents are not modified due to
excessive electric noise.
Memories targeted for memory check depend on each CPU module. Table6.59 shows the
target memories.
Note90
:Checked, :Not
checked
(1) Memory check function overview for each CPU module
(a) Process CPU and Redundant CPU
The data in the executing program memory is checked whether to match the
based data such as user programs and parameters at the time they was written
into the program memory of the CPU module both at STOP to RUN switching and
at END processing. (
(3) in this section.)
If the data in the executing program memory does not match the based data, the
CPU determines that the data in the program memory has been modified and a
stop error, RAM ERROR (error code:1106), occurs.
Note90
Table6.61 Parameter item list
CPU model name
Target memory
Program memory
Device memory
Process CPU
Redundant CPU
Universal model QCPU
Figure 6.123 Program memory check function overview for Process CPU and Redundant CPU
Basic
Note6.88
High
Performance
The Basic model QCPU and High Performance model QCPU do not support the memory check
function.
Basic
High
Performance
Specified steps
Specified steps
Specified steps
Specified steps
Program memory
Based data
Check
Repeated execution
Q12PHCPU,
Q12PRHCPU
Q25PHCPU,
Q25PRHCPU
:124k steps
:252k steps
END 0
END 0
END 0
END 0
Execution of program memory check1)
Execution of program memory check2)
Execution of program memory check3)
Execution of program memory check n)
Scan time
Program memory check
A mount of time required for checking
program memory
