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====== Script Tags ======

Script Tags provide a highly configurable way to define calculation and event raising tags.

Script tags can be written in:

  * C#
  * FLEE (Fast Lightweight Expression Evaluation) - [[https://github.com/mparlak/Flee/wiki/Examples|more info]]


===== Script Tag Templates =====

A number of pre-configured script tags exist to perform the following functions:



==== Calculations ====

  * **Accumulator Calculator** \\ Calculates the accumulated result of a monitored process tag for a given period (e.g. a day).

  * **Aggregation Calculator** \\ Periodically calculate an aggregation of a process tag.

  * **Average Calculator** \\ Periodically calculates the average value of a process tag.

  * **Delta Calculator** \\ Calculates the delta between the value of two input tags.

  * **Delta with Offset Calculator** \\ Calculates the delta between the value of two input tags, then applies an offset.

  * **Energy Based Availability Calculator** \\ Energy-Based Availability (EBA) is the ratio of actual to expected energy production.

  * **Gas Velocity Calculator** \\ Calculates gas velocity using flow rate and pressure.

  * **Normalized Deviation Calculation** \\ Calculates the normalized deviation of a process value.

  * **Ratio Calculator** \\ Calculates the ratio and between two input tags.

  * **Time Based Availability Calculator** \\ Time-Based Availability (TBA) is an energy expression denoting the ratio of a time-period (e.g. a day) when power is available. It does not discriminate the cause of downtime (e.g. a deliberate stop for maintenance, no/low wind conditions).

  * **Time Based Delta Calculator** \\ Monitors the rate of change of a process tag over a time period.

  * **Turbine Status** \\ A turbine has three basic power-production states: 1. Power; 2. No Wind; 3. No Power.

  * **Turbulence Intensity Calculator** \\ Turbulence Intensity (TI) is a measurement of wind speed turbulence. It is the ratio of wind speed StdDev to Mean.

  * **Turbulence Intensity Forecast Calculator** \\ Turbulence Intensity Forecast (TI) is an measurement of wind speed turbulence derived from forecasted Wind and Gust Speed (rather than observed wind speed variance).

  * **Unit Converter** \\ Convert process value from one unit to another.

==== Sensor Quality Checks ==== 

  * **Bad Data Detection** \\ Data quality check that raises alert if monitored tag returns NaN or has a 'bad' status. 

  * **Channel Deviation Detection** \\ Checks for deviation in output from a sensor with two data channels. An alert indicates that one or both of the channels is unreliable. The method is to regularly compare Channel A and Channel B and check if difference is within acceptable instrument error tolerance. Default configuration is to check 24hr average difference 4 times per day.

  * **Flatline Detection** \\ Script tag that checks for flatlining data (i.e. process tags where the tag may be updating regularly, but the sensor value is not changing).

  * **Frozen Signal Detection** \\ Script tag that periodically ensures that newer values are being received for a tag.



==== Process Data Alerts ==== 

  * **Equipment Running Status Monitor** \\ Monitors the running status of a piece of equipment and triggers and resets events when the status changes. 

  * **Fleeting Excursion Monitor** \\ Script tag template for monitoring sensors such as acoustic sand probes that can generate fleeting excursions.

  * **Hi/Lo Limit Monitor** \\ Performs a Hi/Lo limit monitor check.

  * **Limit Monitor** \\ Script tag that periodically monitors a process tag value against a limit using MIN/MAX aggregated data. \\ //Use the FleetingExcursionMonitor template if you require a high degree of accuracy.//

  * **Limit Monitor 1 Precondition** \\ Limit monitor that will only trigger or reset an excursion event if a precondition tag value check is met.

  * **Limit Monitor 2 Precondition** \\ Limit monitor that will only trigger or reset an excursion event if two precondition tag value checks are met.

  * **Limit Monitor 3 Precondition** \\ Limit monitor that will only trigger or reset an excursion event if three precondition tag value checks are met.

  * **Logic Gate Alert** \\ An alert that can be used to summarise the status of multiple alerts using an AND or OR operator. 

  * **Time Based Delta Monitor** \\ Monitors the rate of change of a process tag over a time period.

  * **Value Change Monitor** \\ Monitors a tag and emits an event every time the value of the tag changes.


==== Troubleshooting ====

The Data Core Admin UI shows information related to the processing of an individual Script Tag via the "Info" and "Additional Properties" icons.

{{ :data_core:scripttags-00.png?400 |}}

The Data Core API also exposes information related to all Script Tags for a data source.

  * [DataCoreAdminUrl]/datacore/api/diagnostics/scripting/[dataSourceName]