Access to the SD memory card
If data logging is performed with a small setting of the data collection interval/timing or with a large number of records to be
collected, access (read/write) to the SD memory card occurs so frequently that a delay occurs in completing the access. To
avoid such a delay, use the following workarounds:
• Increase the data collection interval/timing.
• Reduce the number of data records to be collected.
• Lower the frequency of file switching.
Changing the operating status of the CPU module
The operating state of the CPU module should not be changed until the completion of the following operations and
registrations:
• Save of the data in the internal buffer by changing the state of the CPU module from RUN to STOP or instructing the CPU
Module Logging Configuration Tool to stop or suspend the CPU module
• Registering multiple data logging sessions' settings
• Registering data logging settings with any unused folders remaining in the storage memory
*1 Data logging settings are also registered when the CPU module is stopped and run.
• To shorten the time required to register multiple data logging sessions' settings, reduce the number of data
logging sessions.
• To shorten the time required to register data logging settings with any unused folders remaining in the
storage memory, delete the unused folders before registration.
File Operation during Execution of Data Logging
Describes file operation during execution of data logging.
Target file
File
operation
Data logging setting file
Write
Delete
Initialize
Folder delete
Data Logging File
Write
Delete
Folder delete
Initialize
About remote operation
When remote RUN is performed while the data logging function is in the following execution status, the remote RUN may fail.
In that case, wait for a while and retry remote RUN. If remote RUN still cannot be executed, check whether remote RUN is
acceptable and retry remote RUN.
Execution state of data logging function
Data saving into memory card in progress
Registration of the data logging setting from CPU Module Logging
Configuration Tool in progress
RUN operation through switching operation or the RUN contact
During execution of data logging, when the status of the CPU module is switched from STOP to RUN with the RUN/STOP/
RESET switch, or when remote STOP to RUN operation of the RUN contact, it may take time to return to the RUN state.
*1
Operation
During execution of data logging, it is not possible to write or the delete data logging setting file being used.
During execution of data logging, it is not possible to initialize the memory storing the data logging setting file
being executed.
Folders cannot be deleted from the $MELPRJ$ folder in which the data logging setting file is stored.
During execution of data logging, it is not possible to write or delete data, or delete folders corresponding to
the data logging setting file being used.
During execution of data logging, it is not possible to initialize the memory storing the data logging setting file
being executed.
The situation to accept remote RUN
No special relay (Data logging data saving into memory card in progress) is on.
The special relay (data logging preparation) and the special relay (data logging start)
corresponding to the setting number of the data logging setting, which is being
registered in the way shown in the left column, are on.
19.14 Precautions to Take When Using the Data Logging Function
*1
19 DATA LOGGING FUNCTION
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