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6.28 Memory Check Function
6
FUNCTIONS
(b) Universal model QCPU
The data in the executing program memory is checked automatically whether to
match the based data (user program data) at the time they were written into the
program memory of the CPU module.
If the data in the executing program memory does not match the based data, a
stop error, RAM ERROR (error code:1160), occurs.
As for the device memory, if the data cannot be read as devices, a stop error,
RAM ERROR (error code:1161), occurs.
(2) Setting for executing memory check
(a) Process CPU and Redundant CPU
When executing memory check, check the check box for "Check Program
memory" and set the "Capacity to be checked at one time" in the PLC RAS(2) tab
of the PLC parameter dialog box.
Q12PRHCPU and Q25PRHCPU can check program memory by setting "Check
Program memory" on the both control system CPU module and standby system
CPU module.
However, on standby system CPU module, which is the back up mode for the
other one, the program memory must be checked by the fixed "1(256 steps)"
regardless of setting for a capacity to be checked at one time.
(b) Universal model QCPU
No setting is required neither for program memory check nor device memory
check.
Figure 6.124 PLC RAS(2) settings screen
Setting for when
checking a
program
memory
Q12PHCPU,Q12PRHCPU:1 496
(256 steps to 124k steps)
Q25PHCPU,Q25PRHCPU:1 1008
(256 steps to 252k steps)
Setting range
