The value based search enables you to specify numerical search parameters of one or more process characteristics. It will also enable you to quickly observe all the periods that match the search criteria.
If you are interested in conditions such as shut downs, temperatures below certain thresholds, pressures above a safety limit or valves that are fully open, the value based search will help you rapidly identify and visualize periods in the history of a process during which such events occurred.
Note: The value based search will search through the time period highlighted by the context bar (range selected by using the double slider). Time periods that are filtered out or not yet indexed, are excluded from the search.
How to perform a value based search
- From the search menu, select the value based search icon .
- Select a tag and a corresponding search criterion. Different options are available for analog, discrete and digital tags.
- Add multiple conditions by selecting the plus icon . Up to 10 conditions can be combined.
- By clicking on the logic operator in the value based search, the standard 'AND' operator between the conditions can be replaced by an 'OR' operator.
Note: only one operator can be used over all search conditions. More complicated boolean logic based on combinations of AND / OR / NOT operators are currently not supported. However, filters can often be used to indirectly implement more complex logic.
- Adapt the minimum duration for which the results must match the specified boolean conditions in the 'At least during' field. This parameter may be used to filter out noise (brief spikes that satisfy the specified boolean conditions).
Note: The index resolution setting determines the maximum resolution at which results are available. This implies that with a resolution setting of 1 minute, no results will be found with a duration smaller than 1 minute.
- Press the 'Search' button to start the search.
- Wait for the result list to appear. By default, the results are sorted and grouped on time (see working with the search result list to change the order of the results). Results are also indicated in blue under the context bar.
- Navigate through the results list to find results of interest. Visualize them in the focus chart by clicking a result or add them as additional layers by clicking the add layer icon .
Analog and discrete tags (numeric)
- Boolean conditions: '<, <=, >, >=, !=, =' are available.
- 'Constant': time periods in which the selected measurement is constant. For instance, a setpoint value with option 'Constant' would result in time periods corresponding to constant setpoints.
Digital tags (non-numeric)
- Equality '=': time periods with status equal to selected status.
- 'Constant': time periods in which the selected measurement is constant. For instance, a batch ID with option 'Constant' would result in time periods corresponding to the individual batches.
- 'In set': time periods that represent one of the statuses in a specified set. This option allows to identify periods for different statuses (e.g. product grade) using one search.