Trend Indicator Image

Note: For information on overriding default configuration settings, refer to Modify configuration settings.

Trend Indicator Image allows a client application to subscribe via PubSub to the virtual field TrendIndicatorImage.FileName. This field contains the name of the image representing the short-term trend direction of an analog value when compared against certain pre-defined ranges. If the value passes a certain threshold, the backend publishes an image to TrendIndicatorImage.FileName that graphically portrays the change.

The trendIndicatorImageSet table in the RealTime database (RTDB) defines the association between field names and the set of images to use for the different ranges.

The trendIndicatorImageSet table contains the following increase and decrease threshold fields:

• IncreaseThresholds[0-1].Value

• DecreaseThresholds[0-1].Value

For increase thresholds, the system considers the threshold surpassed if the value in the field is greater than the threshold value. For decrease thresholds, the system considers the threshold surpassed if the value in the field falls below the threshold value.

In the event that no threshold is reached, the system uses the NormalRangeImage field.

The %DNADataRoot%/Realtime/config/Settings/RealTime_TrendIndicatorInputFields.json file defines the fields that can be used as the value for this feature. Any field in an analog or rate table that is defined in the RTDB schema as a float data type can be configured as allowed input fields for the Trend Indicator Image calculation. RealTime services must be restarted to apply any changes to this configuration file.

The following fields are pre-configured to be used by the Trend Indicator Image feature:

• analog

  • hilow.rocval

  • TrendIndicator.Value

• rate

  • hilo.rocval

  • TrendIndicator.Value