Mitsubishi 00JCPU User Manual page 330

(2) Setting for memory check
• Select the "Check Program memory" checkbox in the PLC RAS(2) tab of the PLC parameter dialog box.
• Enter a value for "Capacity to be checked at one time".
Setting for program
memory check
Data in the program memories of the CPU modules in the control system and standby system are checked.
If the standby system CPU module is in the backup mode, the data amount to be checked at a time is "1" (256
steps) regardless of setting for "Capacity to be checked at one time".
(3) Execution timing
Data in a memory is checked at the following timing.
• When the CPU module is set from STOP to RUN: All areas in the program memory are checked.
• When END processing is performed: Data are checked at a time by the amount of Capacity to be checked at
one time
(4) Processing time
(a) When the CPU module is set from STOP to RUN
The scan time increases by the processing time shown below.
• Q12PHCPU and Q12PRHCPU: 434ms
• Q25PHCPU and Q25PRHCPU: 882ms
(b) When END processing is performed while the CPU module is in the RUN status
The scan time increases by the processing time shown below.
(Extended scan time) = 3.5
Consider the increase in the scan time when entering a value for "Capacity to be checked at one time" in the
PLC RAS(2) tab of the PLC parameter dialog box.
If the "Capacity to be checked at one time" is set to "4", the processing time is shown below.
3.5 4 256/1024 = 3.5 (ms)
6 - 150
Figure 6.101 PLC RAS(2) tab
256 steps.
(Capacity to be checked at one time)
Setting range
Q12PHCPU, Q12PRHCPU:
1 to 496(256 steps to 124K steps)
Q25PHCPU, Q25PRHCPU:
1 to 1008(256 steps to 252K steps)
256
(ms)
1024