The Sum algorithm calculates the total value of the good quality raw values in the sample. The result of the sum algorithm has a timestamp that matches the start time of the sample.
A point with historic enabled has the following values and time stamps:
|
Timestamp |
Raw Historic Value |
|---|---|
|
13:01:00 |
20.11 |
|
13:01:10 |
20.62 |
|
13:01:20 |
20.78 |
|
13:01:30 |
21.02 |
|
13:01:40 |
21.65 |
|
13:01:50 |
21.21 |
A Trend is configured to show the point’s historic data graphically. A processed historic trace is configured to use the Sum algorithm. The trace has an Interval setting of 1M (1 minute), which means that at the start of every minute, ClearSCADA calculates the sum value using the raw historic values in the 1 minute sample (which starts from the beginning of the minute).
At 13:01, ClearSCADA has to calculate the sum value. To do this, it adds up the good quality raw historic values in the period 13:01:00 to 13:01:59. The result is the sum value (the sum total) and in this case, it is 46.61.
On the trace, the 46.61 value is plotted at 13:01 on the X-axis (13:01 being the start time of the sample).
Further Information