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Editing settings for variables

Requirement

You have opened a variable for editing in the parameter list.

Description

The properties of a variable can be defined.

  • Unit
    You can either accept the transferred unit or specify your own unit.
  • Acquisition category:
    Here you determine how the value is acquired and stored. The acquisition category is linked directly to an aggregation function. As soon as you use the variable in a widget, the respective aggregation function is automatically selected:
    *Process value (ProcessValue) => aggregation function: Average
    • Power value (Power) ⇒ aggregation function: Average *Consumption value (Energy) ⇒ aggregation function: Sum
    • Flow value (Flow) ⇒ aggregation function: Average *Quantity value (Amount) ⇒ aggregation function: Sum
    • Count value (Counter) ⇒ aggregation function: Counter
      When you select the acquisition category "Counter", you can define additional settings for each counter used.
      Additional information on the counting method of the individual counters can be found here: "Counter" acquisition category
    • Status value (State)
  • "The value is aggregated" function
    If the value is not aggregated, the values are continuously (actual values) transferred to the platform when the value changes. The currently transferred value is valid until the next value is transferred to the platform. When the value is aggregated, the value is always valid for the last cycle, for example, 15 minutes.
    You can find additional information on the aggregation functions here: Aggregation functions

Data gaps

Data gaps occur, for example, when the connection to the network is interrupted. No data is transferred from the plant during the interruption.

When you have activated the "The value is aggregated" function and are using an acquisition category with the "Sum" aggregation function, data gaps will distort the final result.

Procedure

To extend the declaration of a variable, follow these steps:

  1. In the parameter list, open a variable for editing.
  2. Select the desired properties.
    In addition to the acquisition category, the data type of the variable is displayed.
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Filtering variable values

If variables are assigned values that do not reflect reality, e.g. 0 (zero) in the event of a temporary connection failure, calculations and graphical representations are displayed in a distorted manner.

Enable filtering to discard any values that are not to be included into calculations. This is only possible on variables, not on KPIs.

Currently there are multiple filtering methods available:

  1. Min-Max
    Filtering is based on a lower and upper limit. Values that are above or below will be discarded.
  2. Static Delta
    The static delta filters out the value that is not in the calculated window. The window is the sum/difference of the previous valid value and the configured positive/negative delta.
  3. Counter
    All values with a higher difference between two values are discarded.

Interpolation of variable values

If data points are missing in a time series of values, you can have them replaced.

For replacement you need to fill out the acquisition category of a variable. To do so, choose an acquisition cycle at the top of variable configuration.

Currently there are multiple filtering methods available:

  1. Linear Interpolation
    Missing values are filled based on a linear interpolation using the boundary values.
  2. Cubic Spline
    Missing values are filled based on a spline interpolation using the boundary values.
  3. Last used
    The last available value will be used to fill the gaps.
  4. Replacement value
    The entered value will be used as replacement value.

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