...
Selection of a value type of the historical value. The possible types are shown in the following table.
| Label | Value type |
| Int-Integer | Integer |
| Re-Real | Real |
| Bo-Boolean | Boolean |
Note: Value type may be defined for the archive purpose Calculate archived values by defined statement only.
...
Technological limits are effective only for historical values which are calculated by D2000 Archiv (evaluated and statistical historical values). There are 4 limits defined: VHL, HL, LL and VLL. Limit can be defined either directly – by the value entry into the input field, or its value can be determined by a system object (dynamic limit) – the button right from the input field.
| VHL | Very High Limit - the highest limit |
| HL | High Limit |
| LL | Low Limit |
| VLL | Very Low Limit - the lowest limit |
Values of the individual limits determine the state of the historical value according to its value. The relation value- limits gives six possible states.
| Limit | Object state according to relation Value - Limit |
| Above VHL (object value > VHL) | |
| VHL | |
| Above HL (HL < object value < VHL) | |
| HL | |
| Normal (LL < object value < HL) | |
| LL | |
| Bellow LL (VLL < object value < LL) | |
| VLL | |
| Bellow VLL (object value < VLL) |
As the limits can be dynamic (determined by the object value), a situation when the relation VLL<LL<HL<VHL is not valid (the limits crossing) can occur. The historical value is then in Limit Problem state.
...
Optimisation of old values processing coming from communication (automatically or as a result of TELL command GETOLDVAL) or values of remote tags (as a result of TELL command GETOLDVAL).
If the checkbox is checked, during processing of old value the archive database is queried whether the value is already present there. If it exists, the value is discarded (and recalcs of statistical or calculated archived values which use this primary archive value are not performed either).
Note: Optimisation is useful e.g. for archiving of I/O tags from communication using the protocol IEC62056-21:2002 File I/O. Its communication files contain several historical values (which KOM process sends as old values) and one new value for every I/O tag.
...
- Continuous - continuous (on the fly) calculation. Result values are calculated on the fly and they are automatically available (in dependence on the system load). A disadvantage of the method is a higher demand on the computing power (especially for frequent changes of primary historical values).
- On demand - calculation is executed and result is stored to the archive on demand. The demand can be generated by the action CALCONDEMANDSTAT or the Tell command RECALC).
Note: historical value calculated on demand should not have any depending historical values calculated continuously, because the result would be wrong. - On read - calculation is executed as a result of a read request. An advantage of this method is that values are not stored in the database so they don't occupy any disk space. There is no possibility of re-calculation in case of writing delayed data into the archive. A disadvantage is a necessity to read source data and calculate it for each read demand.
Note: historical value calculated on read should not have any depending historical values calculated continuously or on demand, because the result could be wrong (due to delayed data) or the calculation could be ineffective (multiple calculations of a single on read object if it is used by several other historical values).
...
Note: For archives filled from script, this setting does not directly affect anything - the data has a time stamp with which it was stored from the script. It however affects the calculation of statistics and whether statistics are calculated from the value at the edge of the interval.
| Kotva | ||||
|---|---|---|---|---|
|
...
When archiving into the statistical archive it is possible to use these implemented functions.
| Function | Meaning |
|---|---|
| None | No function. |
| Average * | Arithmetical average of all archive object values. |
| W-Average * | Weighted arithmetical average of all archive object values. |
| Integral | Time integral of historical values. |
| Sum | Sum of archive object values. |
| Maximum | Maximum of archive object values. |
| Minimum | Minimum of archive object values. |
| Count | Number of archive object values. |
| Filter | Applying a filter for value storing into the statistical archive. |
| Increment | Increment between values. Parameter (Compare value) – weight of impulse. The result will be the impulse multiplied by its weight. Weight of 1 will ensure standard behaviour. |
| Delta | Delta between values. Parameter (Compare value) – weight of impulse. The result will be the impulse multiplied by its weight. Weight of 1 will ensure standard behaviour. |
| EcoAvg | Average of the object values within the elapsed time period (Period parameter in Time parameters tab) according the methodology based on flags of individual values entering the statistic. The same purpose is fulfilled by the function %EcoAveR, that is implemented for eval tags. |
| GT Time (>) | The function calculates the time, during which the value of the historical value was greater than the entered constant (Compare value). |
| GE Time (>=) | The function calculates the time, during which the value of the historical value was greater or equal to the entered constant (Compare value). |
| LT Time (<) | The function calculates the time, during which the value of the historical value was lower then the entered constant (Compare value). |
| LE Time (<=) | The function calculates the time, during which the value of the historical value was lower or equal to the entered constant (Compare value). |
| Maximum in time interval | Obsolete - do not use! |
| Minimum in time interval | Obsolete - do not use! |
| Number of local maximums | |
| Number of local minimums | |
| Sum of positive values | Sum of positive values of the historical value. |
| Sum of negative values | Sum of negative values of the historical value. |
| Average of positive values | Arithmetical average of positive values of the historical value. |
| Average of negative values | Arithmetical average of negative values of the historical value. |
| Sum of increments | Sum of increments for given time interval. Parameter (Compare value) – weight of impulse. The result will be the impulse multiplied by its weight. Weight of 1 will ensure standard behaviour. |
| Time slice** | Object value in given time moments. |
| Sample standard deviation | The function calculates the sample standard deviation of all values of the archive object. |
* For non-periodical values we recommend you to use the W-Average (weighted average) function and the Average function for periodical values.
** The function allows recalculation of the historical value if historical values archived primarily have been changed.
...
- Continuous - continuous (on the fly) calculation. Result values are calculated on the fly and they are automatically available (in dependence on the system load). A disadvantage of the method is a higher demand on the computing power (especially for frequent changes of primary historical values).
- On demand - calculation is executed and result is stored to the archive on demand. The demand can be generated by the action CALCONDEMANDSTAT or the Tell command RECALC). Note: historical value calculated on demand should not have any depending historical values calculated continuously, because the result would be wrong.
- On read - calculation is executed as a result of a read request. An advantage of the method is that values are not stored in the database so they don't occupy any disk space. There is no chance of wrong calculation in case of writing delayed data into the archive. A disadvantage is a necessity to read source data and calculate it for each read demand.
Note: historical value calculated on read should not have any depending historical values calculated continuously or on demand, because the result could be wrong (due to delayed data) or the calculation could be ineffective (multiple calculations of a single on read object if it is used by several other historical values).
...