Checking Number Of Erasures On Standard Rom - Mitsubishi MELSEC-Q Series User Manual

5
SETTINGS AND PROCEDURES BEFORE OPERATION

5.9 Checking Number of Erasures on Standard ROM

The standard ROM built in the C Controller module is used to store various parameters
and user programs.
Since a flash ROM is used as the standard ROM, it has a limit on the number of writes
(life).
When writing data to the standard ROM on a regular basis, it is necessary to take into
account the life of the standard ROM.
This section explains the life of the standard ROM and how to check its writing frequency.
(1) Standard ROM life
(2) Confirmation of standard ROM writing frequency
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- 52 5.9 Checking Number of Erasures on Standard ROM
Data can be written to the same area of the standard ROM to the limit of 100,000
times.
The following shows the standard ROM life (reference value) in the case where files
are copied (written) every day.
Standard ROM life (days) = 600000/total size of files copied one day (MB)
* 1 When the file size is 512 or less bytes, regard it as 512 bytes for calculation.
The frequency of writing to the standard ROM can be confirmed by obtaining the
maximum number of standard ROM erasures from the user program using the
following function.
Include the following function in the user program so that the standard ROM life can
be estimated.
• Obtain the number of erasures by pllnfo[7] of the QBF_ReadStausEx function.
• If the value returned by the above function exceeds 100,000, the writing speed to
the standard ROM will decrease, or writing to the standard ROM will be
terminated with an error, for example.
Also, if the value returned by the above function exceeds 100,000, the event
history is registered. (
When the number of erasures exceeds 100,000 times, replace the C Controller
module.
POINT
Do not write data from the user program to any file in the standard ROM.
When writing data to a file from the user program, use the file in the
CompactFlash card.
Section 9.2.3)
*1