AFData.PlotValuesAsync Method
- Last UpdatedNov 18, 2025
- 4 minute read
- PI System
- AF SDK 2024 R2
- Developer
Retrieves values over the specified time range suitable for plotting over the number of intervals (typically represents pixels).
Namespace: OSIsoft.AF.Data
Assembly: OSIsoft.AFSDK (in OSIsoft.AFSDK.dll) Version: 3.1.1.1182
Syntax
public Task<AFValues> PlotValuesAsync( AFTimeRange timeRange, int intervals, UOM desiredUOM, CancellationToken cancellationToken = default )
Public Function PlotValuesAsync ( timeRange As AFTimeRange, intervals As Integer, desiredUOM As UOM, Optional cancellationToken As CancellationToken = Nothing ) As Task(Of AFValues) Dim instance As AFData Dim timeRange As AFTimeRange Dim intervals As Integer Dim desiredUOM As UOM Dim cancellationToken As CancellationToken Dim returnValue As Task(Of AFValues) returnValue = instance.PlotValuesAsync(timeRange, intervals, desiredUOM, cancellationToken)
public: Task<AFValues^>^ PlotValuesAsync( AFTimeRange timeRange, int intervals, UOM^ desiredUOM, CancellationToken cancellationToken = CancellationToken() )
member PlotValuesAsync : timeRange : AFTimeRange * intervals : int * desiredUOM : UOM * ?cancellationToken : CancellationToken (* Defaults: let _cancellationToken = defaultArg cancellationToken new CancellationToken() *) -> Task<AFValues>
Parameters
- timeRange
- Type: OSIsoft.AF.TimeAFTimeRange
The bounding time range for the plot values request. - intervals
- Type: SystemInt32
The number of intervals to plot over. Typically, this would be the number of horizontal pixels in the trend. - desiredUOM
- Type: OSIsoft.AF.UnitsOfMeasureUOM
The desired unit of measure for the returned value. If , then the value is returned in the unit of measure specified by the associated attribute's DefaultUOM property. - cancellationToken (Optional)
- Type: System.ThreadingCancellationToken
A cancellation token used to abort processing before completion. Passing the default CancellationToken.None will run to completion or until the PIConnectionInfo.OperationTimeOut period elapses.
Return Value
Type: TaskAFValuesReturns a task whose result is an AFValues collection with values that will produce the most accurate plot over the time range while minimizing the amount of data returned.
Exceptions
| Exception | Condition |
|---|---|
| AggregateException | Asynchronous methods throw AggregateException on failure which will contain one or more exceptions containing the failure. |
Remarks
| This method, property, or class is not available in the legacy .NET 3.5 version of the SDK. |
| You must have ReadData security rights to read a data value. |
| This call might use a background task to complete some of its work. See the Threading Overview for some matters to consider when execution transitions to another thread. |
| Asynchronous data calls in AF SDK attempt to do as much work as possible asynchronously. If no work can be done asynchronously, then the SupportedDataMethods will report that asynchronous calls are not supported. If an attribute uses a Formula or other calculated data reference has any input that supports asynchronous calls, then the attribute will support asynchronous calls. When making an asynchronous data call, input data will be acquired asynchronously when possible or synchronously otherwise. Data calls that require partitioning across versions will always fall back to synchronous calls. |
| Impersonation of AF SDK asynchronous calls relies on the .NET framework's built-in support for flowing execution context across asynchronous points. When making these calls while impersonating, the thread or runtime must be configured to propagate the impersonation across these asynchronous points (see the SecurityContext documentation for details). |