Mitsubishi Electric MELSEC iQ-R Series User Manual page 30

Precautions
When the following conditional expression is true, data is sampled, not with a sequence scan time (ST), but with a sampling
interval (ST').
• Conditional expression
 > 1
(Round up after the decimal point) = (0.4  Number of settings where the high speed sampling is specified - 0.2)  ST [ms]
• Sampling interval
ST' = ST  
Ex.
When there are 20 settings (the total of data logging setting, event logging setting, and report setting) in which the high speed
sampling is specified and the sequence scan time is 3 ms
 = (0.4  20 - 0.2)  3 = 3 (Round up after the decimal point of 2.6)
When  > 1, sampling interval (ST') = 3  3 = 9
Data is sampled, not with a sequence scan time (3 ms), but with the sampling interval (9 ms).
General sampling
This function samples data from the control CPU, other CPU in a multiple CPU configuration, or a CPU module on other
stations.
The sampling interval can be specified in seconds unit (0.1 to 32767) or at the best time possible.
Since general sampling is not synchronized with the control CPU's sequence scan, data inconsistency may
occur. To synchronize the data sampling to the sequence scan, use high speed sampling.
For details on the data inconsistency, refer to the following:
(MELSEC iQ-R High Speed Data Logger Module User's Manual (Startup))
■Timing of data sampling when "Time specification" is specified
Data is sampled at each specified interval.
If the data cannot be sampled at the specified interval, it will be sampled with the time interval required to acquire the data.
Specified interval
■Timing of processing when "Time interval specification" is specified
Samples data at the specified time interval (hour, minute, or second) from exactly midnight everyday, exact hour, or exact
minute.
• Available time units and intervals
Unit
Hour
Minute
Second
Ex.
When the time interval of 30 minutes is specified and power ON at 10:15.
Data is sampled at the intervals of 30 minutes from 10:30.
10:00
Power ON at 10:15
1 FUNCTION
28
1.1 Data Logging Function
Time required to obtain
data
Constant
Interval
1, 2, 3, 4, 6, 8, 12, 24
1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
10:30 11:00
Sampling Sampling
Time required to obtain
data
Specified interval
Constant
Sampling
11:30 12:00
Sampling Sampling
Time required to obtain
data
Specified interval
Constant
Sampling
12:30
Sampling