iphist:index
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iphist:index [2021/06/25 15:52] – [IPHist - IPHist replication] su | iphist:index [2021/06/28 08:29] – [Archiving Model] su | ||
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===== Introduction ===== | ===== Introduction ===== | ||
- | Intelligent Plant' | + | Intelligent Plant' |
+ | |||
+ | For many data sources (such as Modbus, MQTT, and more), it is possible | ||
+ | |||
+ | Additionally, | ||
- | eg. Modbus, OPC, MQTT, etc.. The majority of data can all be automatically recorded and mostly filtered with default exception and compression rules. | ||
=====How Historians Work - Exception and Compression===== | =====How Historians Work - Exception and Compression===== | ||
Line 17: | Line 21: | ||
+ | ===== Data Query Types ===== | ||
+ | |||
+ | IP Historian supports a number of different types of data queries. | ||
+ | |||
+ | ==== Snapshot ==== | ||
+ | |||
+ | Snapshot queries return the current values of the tags polled. | ||
+ | |||
+ | |||
+ | ==== Raw ==== | ||
+ | |||
+ | A raw query returns the unprocessed data for a tag i.e. the actual data points persisted in the historian' | ||
+ | |||
+ | Raw queries are generally not advised as they are likely to return a bulky result-set that may well be cropped by size constraints. In the majority of cases, a plot or aggregated data query can return a data set that is acceptable for the task at hand. | ||
+ | |||
+ | |||
+ | ==== Plot ==== | ||
+ | |||
+ | Plot queries return a best-fit data set for a given query time range and level of granularity, | ||
+ | |||
+ | |||
+ | ==== Values-at-Times ==== | ||
+ | |||
+ | A values-at-times query is used to retrieve the value of a tag at specified points in time. IP Historian will return the closest raw value at or before each specified sample time. | ||
+ | |||
+ | |||
+ | ==== Aggregated ==== | ||
+ | |||
+ | Aggregated queries can be used to perform ad hoc processing and filtering of raw historical data based on a query time range and sample interval. IP Historian supports a number of aggregation functions, as described below: | ||
+ | |||
+ | == ANNOTATIONCOUNT == | ||
+ | |||
+ | Groups the raw data for a tag into buckets using the specified sample interval and returns the number of annotations defined on a tag in each bucket. | ||
+ | |||
+ | == AVG == | ||
+ | |||
+ | Groups the raw data for a tag into buckets using the specified sample interval and computes the mean value of a tag in each bucket. | ||
+ | |||
+ | == COUNT == | ||
+ | |||
+ | Groups the raw data for a tag into buckets using the specified sample interval and returns the number of raw samples in each bucket. | ||
+ | |||
+ | == DELTA == | ||
+ | |||
+ | Groups the raw data for a tag into buckets using the specified sample interval and returns the signed difference between the first and last raw samples in each bucket. | ||
+ | |||
+ | == INTERP == | ||
+ | |||
+ | Groups the raw data for a tag into buckets using the specified sample interval and interpolates a value at each bucket start and/or end time using the values from the previous and current buckets. | ||
+ | |||
+ | == MIN == | ||
+ | |||
+ | Groups the raw data for a tag into buckets using the specified sample interval and returns the minimum value from each bucket. Note that the original raw samples are returned, so the values are the " | ||
+ | == MAX == | ||
- | =====Historical Vs. Snapshot===== | + | Groups the raw data for a tag into buckets using the specified sample interval and returns the maximum value from each bucket. Note that the original raw samples are returned, so the values are the " |
+ | == PERCENTBAD == | ||
- | =====Functions | + | Groups the raw data for a tag into buckets using the specified sample interval |
- | ==== SNAPSHOT ==== | + | == PERCENTGOOD |
- | Snapshot queries are used to request | + | Groups |
- | ==== AVG ==== | + | == RANGE == |
- | Returns | + | Groups |
- | ==== MIN ==== | + | |
- | Returns the minimum value for each interval (the lowest value observed in that time) | + | == STDDEV |
- | note, with the two filters applied - there is no loss in resolution of the minimum value, that minimum is still recorded and delivered. | + | |
- | ==== MAX ==== | + | |
- | Returns | + | Groups |
- | ==== STDDEV ==== | + | == TAVG == |
- | Returns the standard deviation of the values in each interval | + | Calculates a time-based rolling average for a tag. |
- | ==== INTERP ==== | + | == VARIANCE |
- | returns an interpolated value for the exact time of the interval | + | Groups the raw data for a tag into buckets using the specified sample |
- | ==== PLOT ==== | + | |
- | Plot is used to draw applicable graphs of data with minimal data exchange and loss of data. for any interval the maximum and minimum value will be retained, along with the shape of the values that were recorded as far as can be done with the interval passed. | ||
+ | ==== Annotations ==== | ||
+ | IP Historian allows annotations to be recorded against tags at specific points in time. Annotations can be used to track or highlight events a tag value exceeding an operating limit, an action taken as part of a workflow, and so on. | ||
- | ==== RAW ==== | + | ==== Specifying Query Time Ranges |
- | A raw query returns | + | As part of the Data Core data connectivity layer, IP Historian can accept query time ranges specified |
- | Raw queries are generally not advised as they are likely to return a bulky result-set that may well be cropped by size constraints. If connecting to a Process Data Historian, it is far more efficient to request “Get Processed Data” with an “INTERP” function instead. | ||
+ | ===== Archiving Model ===== | ||
- | =====Specifying Date-Ranges===== | + | IP Historian supports multiple indexing models depending on the requirements of the data being recorded: |
- | Historical | + | * "One Big Index" - optimised for constant or infrequently-changing values. |
+ | * "Index per Day/ | ||
- | For '' | + | When recording process data, we normally recommend "Index per Month" as the optimal indexing period. |
- | Relative values can be specified using '' | ||
- | =====Archiving Model===== | ||
- | IPHist supports | + | ===== Backing Up ===== |
- | A Single index for all data (recommended for constants, or values that change infrequently) | + | Indexes can be backed up and restored on another IP Historian instance. |
- | An index per year, month, etc.. | + | |
- | we normally recommend index per month as the indexing period for process data. | + | |
- | =====Backing Up===== | + | |
- | Indexes can be backed up and restored on another IPHist instance, | ||
- | =====System Requirements===== | ||
+ | ===== System Requirements ===== | ||
- | =====Licensing===== | ||
+ | ===== Licensing ===== | ||
- | IPHist instances that are connected | + | When connecting IP Historian |
- | The free 1000 tag license | + | |
- | Instances | + | IP Historian deployments |
iphist/index.txt · Last modified: 2022/08/29 12:05 by su