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CHAPTER 3 FUNCTIONS
3
3.28 Program Cache Memory Auto Recovery Function
3.28 Program Cache Memory Auto Recovery Function
This function is to restore the error location automatically by using data in the program memory, which are stored in the
flash ROM, when the memory check function ( Page 250, Section 3.27) detects an error in the program cache
memory. This function enables the CPU module to continue its operation even if an error such as change of data in the
program cache memory occurs due to noise.Note 3.18
(1) Execution condition
The function is executed when the following conditions are all met.
• The CPU module is in RUN status.
• Data in the program memory match those in the program cache memory.
Note that the function is not executed in the following conditions even though the above conditions are met, and
"RAM ERROR" (error code: 1160) occurs.
• The change of data in the program cache memory was detected while the following operations were being
performed with the CPU module during RUN.
: The auto recovery processing is performed and no error occurs. : An error occurs depending on the condition. ×: An error occurs.
*1 If the change of data is detected while data in the program cache memory are being transferred to the program memory
(while the following window is being displayed on the programming tool), the auto recovery processing is not performed
and an error occurs.
• The change of data in the program cache memory was detected by SFC program.
*2
• The change of data in the program cache memory was detected by the dedicated instruction such as the
S(P). instruction.
*2
• The change of data in the program cache memory was detected by the rise instruction or the fall
instruction.
*2
• The data in the program cache memory was not restored due to the failure of the memory.
*2 The High-speed Universal model QCPU and Universal model Process CPU execute the function when the change of
data in the program cache memory is detected by the corresponding factors above. (Data are automatically recovered
and no error occurs.)
Note 3.18
Before executing the function, check the version of the CPU module used.
( Page 465, Appendix 2)
Operation item
Universal model QCPU with a serial number
(first five digits) of "12121" or earlier
Universal model QCPU with a serial number
(first five digits) of "12122" or later
Online change (ladder mode) ×
*1
Password registration (program files) ×
Program memory batch download ×
*1
Export to ROM format ×
Write to PLC (device comments) ×
*1
Universal
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