Sampling Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

1.6

Sampling Function

This function samples target data from a CPU module.
• To sample data in each sequence scan, a CPU module supporting the sequence scan synchronization
sampling function is required.
• Data sampling in each sequence scan of a C intelligent function module is a best effort function. Since the
processing time varies depending on the setting and the status of other devices, this function may not
perform at the set sampling interval. Run the system by fully verifying the processing time of each function
when constructing it.
Data sampling in sequence scan
This function samples target data by synchronizing with a sequence scan from a control CPU module by using the sequence
scan synchronization sampling function of a control CPU module.
It also transfers device values to a C intelligent function module at the END processing of each scan in a control CPU module,
then stores them in the temporary area in the module. The device values stored in the temporary area can be acquired with a
C intelligent function module dedicated function.
For the sequence scan synchronization sampling function, refer to the following:
MELSEC iQ-R CPU Module User's Manual (Application)
Timing of data sampling in each sequence scan
Target data is sampled for each sequence scan time of a CPU module.
When a CPU module is stopped, target data is not sampled.
Sequence scan time
Step 0 END
END processing
Sampling
At the time of data sampling in each sequence scan, scan time increases due to transfer from a CPU module to a C intelligent
function module.
For the influence on the sequence scan time, refer to the following:
MELSEC iQ-R CPU Module User's Manual (Application)
Temporary area at the time of data sampling
When executing the C intelligent function module dedicated function (CITL_SetCollectData), the temporary area is reserved
in the memory with the following formula.
• Temporary area size: Number of retainable records  (Header information size + (Number of sampled points  2 bytes))
The size of the temporary area varies depending on the number of sampling points and the number of retainable records.
*1 A record refers to data to be sampled in one sequence scan.
When executing the C intelligent function module dedicated function (CITL_SetCollectData) again, the temporary area for the
previous settings is released, and the one calculated with new settings is reserved. To release the temporary area only,
specify NULL for the storage destination for data set in the data sampling in each sequence scan setting (plSetData) of the C
intelligent function module dedicated function (CITL_SetCollectData).
Sequence scan time Sequence scan time
0 END 0
END processing END processing
Sampling
Sequence scan time
END 0 END
END processing
Sampling Sampling
Sequence scan time
0 END
END processing
Sampling
1 FUNCTION
1.6 Sampling Function
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