Mitsubishi MELSEC Q series User Manual page 76

(3) Holding and clearing the data logging setting
The data logging setting registered to the CPU module is latched. Even if the CPU module is powered off and on
or is reset, the data logging can be performed again with registered setting data. However, the data logging status
is cleared when the storage destination is an SD memory card and any of the following conditions is met. Write
the setting data again.
• The CPU module is powered off and on or is reset with the SD memory card removed.
• When the CPU module change function with SD memory card is used, the CPU module is powered off and
on or is reset with no setting data stored in the SD memory card. (If the SD memory card after replacement
contains setting data, registration is performed with the data.)
(4) Availability of data logging
Data logging can be executed through another station or a serial communication module on the network.
For the same setting number, however, simultaneous execution by multiple routes is not allowed.
(5) Execution of data logging
Once data logging is started, it can be executed only with the memory where the setting file of the currently
executing data logging is stored. (A data logging setting file stored in a different memory cannot be used.)
(6) Start operation after stop of trigger logging
When data logging is restarted after stop or temporary stop of data logging before completing trigger logging,
data are collected from the initial status before the trigger.
(7) When data logging registration failed
If a part of multiple data logging settings fails to be registered, successfully registered data loggings only will be
executed. Note that, however, registration by auto logging is different in operation.
( Page 78, Section 7.2 (2))
(8) Sampling interval setting in "Sampling"
When "Time specification" is set for the sampling interval in "Sampling", sampling is executed as interrupt
processing. Therefore, scan time will be extended and a watchdog timer error may occur in the following cases.
• Short sampling interval and many data logging executions per scan
• Large volume of data to be sampled, and long data logging processing time
(9) Checking the sampling interval
Depending on the accuracy of the clock, some errors may be observed in the information output to the "Date"
column. Check the sampling intervals with the information output to the "Sampling interval" column. For the
accuracy of the clock, refer to the following.
User's Manual (Hardware Design, Maintenance and Inspection) for the CPU module used
(10)When a file register is specified
When a file register is specified in "Device specification" in "Sampling" or "Trigger", do not change the block
numbers and file name of the file register after registration of the data logging. Doing so may disable normal
collection of logging results.
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