iphist:index
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iphist:index [2021/06/25 15:52] – [IPHist - IPHist replication] su | iphist:index [2021/08/16 12:15] – [System Requirements] 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===== | ||
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+ | ===== 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 == | ||
+ | |||
+ | 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 == | ||
+ | |||
+ | Groups the raw data for a tag into buckets using the specified sample interval and computes the percentage of raw samples in each bucket that have a quality flag set to " | ||
+ | |||
+ | == PERCENTGOOD == | ||
+ | Groups the raw data for a tag into buckets using the specified sample interval and computes the percentage of raw samples in each bucket that have a quality flag set to " | ||
- | =====Historical Vs. Snapshot===== | + | == RANGE == |
+ | Groups the raw data for a tag into buckets using the specified sample interval and returns the absolute difference between the first and last raw samples in each bucket. | ||
- | =====Functions and Aggregations===== | + | == STDDEV |
- | ==== SNAPSHOT ==== | + | Groups the raw data for a tag into buckets using the specified sample interval and returns the standard deviation for each bucket. |
- | Snapshot queries are used to request the current value of an instrument (or instruments). For example, you might have a digital thermometer that you can poll to find out what the current temperature is. When you perform a snapshot query, you don't need to specify any parameters other than the names of the instruments that you want to poll. | + | == TAVG == |
- | ==== AVG ==== | + | Calculates a time-based rolling average for a tag. |
- | Returns the average value at interavals defined by the query interval ie adds up all values and returns the average | + | == VARIANCE |
- | ==== MIN ==== | + | |
- | Returns | + | Groups |
- | note, with the two filters applied - there is no loss in resolution of the minimum value, that minimum is still recorded | + | |
- | ==== MAX ==== | + | |
- | Returns the maximum value for each interval - as above this is the maximum observed value in that interval | ||
- | ==== STDDEV | + | ==== Annotations |
- | Returns the standard deviation of the values | + | IP Historian allows annotations to be recorded against tags at specific points |
- | ==== INTERP ==== | ||
- | returns an interpolated value for the exact time of the interval (taking the value recorded before and after the interval) - if interp is used at a simliar rate to the original data samples then it tends to return the same values that were recorded (within a reasonable tolerance as defined by exception and compression) if this is called at a resolution that is lower than that, it may miss maximums, and minimums | + | ==== Specifying Query Time Ranges |
- | ==== PLOT ==== | + | |
- | Plot is used to draw applicable graphs | + | As part of the Data Core data connectivity layer, IP Historian can accept query time ranges specified |
+ | ===== Archiving Model ===== | ||
+ | IP Historian supports multiple indexing models depending on the requirements of the data being recorded: | ||
- | ==== RAW ==== | + | * "One Big Index" - optimised for constant or infrequently-changing values. |
+ | * "Index per Day/ | ||
- | A raw query returns the unprocessed | + | When recording process |
- | 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. | ||
+ | ===== Backing Up ===== | ||
- | =====Specifying Date-Ranges===== | + | Indexes can be backed up and restored on another IP Historian instance. |
- | Historical data queries will expect a date-range. | ||
- | For '' | + | ===== System Requirements ===== |
- | Relative values can be specified using '' | + | See [[app_store_connect:system_requirements|See App Store Connect System Requirements]]. |
- | =====Archiving Model===== | + | |
- | IPHist supports | + | However, note the system requirements should be adjusted for the particular use-case of the historian. If you intend to support historization of large data volumes and intensive data queries, a more powerful spec is required. Please consult with the Intelligent Plant support team for detailed guidance. |
- | A Single index for all data (recommended for constants, or values that change infrequently) | + | ===== Configuration Best Practice |
- | 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, | + | Details to follow. |
- | =====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