Read a network variable using measurement studio

[Dhomfray]

I can read a network variable when it has changed by using the following code Public Class Form1 Private WithEvents SS_ThermoRec_Delay As NetworkVariableSubscriber(Of Double) SS_ThermoRec_Delay = New NetworkVariableSubscriber(Of Double)("\\192.168.10.2\SS_Real Time Variable Library\SS_ThermoRec_Delay") SS_ThermoRec_Delay.Connect() Private Sub SS_Pulse_Type_Data_Updated(ByVal sender As System.Object, ByVal e As NationalInstruments.NetworkVariable.DataUpdatedEventArgs(Of Int32)) Handles SS_Pulse_Type.DataUpdated SS_txtPulseType.Text = e.Data.GetValue End Sub End Class I appreciate I am being dumb but how do I just read a network variable I would like to say Variable 1 = Variable 2 * SS_ThermoRec_Delay.Value What is the call to get the data. I would preferably not use bindings cheers

[Dhomfray]

I can read a network variable when it has changed by using the following code

Public Class Form1

Private WithEvents SS_ThermoRec_Delay As NetworkVariableSubscriber(Of Double)

SS_ThermoRec_Delay = New NetworkVariableSubscriber(Of Double)("\\192.168.10.2\SS_Real Time Variable Library\SS_ThermoRec_Delay")

SS_ThermoRec_Delay.Connect()

Private Sub SS_Pulse_Type_Data_Updated(ByVal sender As System.Object, ByVal e As NationalInstruments.NetworkVariable.DataUpdatedEventArgs(Of Int32)) Handles SS_Pulse_Type.DataUpdated SS_txtPulseType.Text = e.Data.GetValue

End Sub

End Class

I appreciate I am being dumb but how do I just read a network variable I would like to say

Variable 1 = Variable 2 * SS_ThermoRec_Delay.Value

What is the call to get the data. I would preferably not use bindings cheers

[nickb]

Hello -

Instead of using a NetworkVariableSubscriber object, you should create a NetworkVariableReader object.  Then you can get your data by calling reader.ReadData();

For more information, take a look at the OnDemandReader example located at:

<MeasurementStudio_version>\DotNET\Examples\NetworkVariable\Basic\vb\OnDemandReader

NickB

National Instruments

[Dhomfray]

Thanks for that

So I can use the variables for event as well as read them I have made a subscriber and a reader as I have tried the following code and had some issues:

Public Class Form1
	Private WithEvents SS_ThermoRec_Delay As NetworkVariableReader(Of Double)
	SS_ThermoRec_Delay = New NetworkVariableReader(Of Double)("\\192.168.10.2\SS_Real Time Variable Library\SS_ThermoRec_Delay")
	SS_ThermoRec_Delay.Connect()

	Private Sub SS_ThermoRec_Delay_Reader_Data_Updated(ByVal sender As System.Object, ByVal e As NationalInstruments.NetworkVariable.DataUpdatedEventArgs(Of Int32)) Handles SS_ThermoRec_Delay_Reader.DataUpdated
             SS_ThermoRec_Delay_Reader.Text = e.Data.GetValue
	End Sub
End Class

It doesn’t like the Handles SS_Pulse_Type.DataUpdated – it says Event ‘DataUpdated’ cannot be found

What I have therefore done is have a subscriber and a reader pointing at the same variable

Public Class Form1
	Private WithEvents SS_ThermoRec_Delay_Reader As NetworkVariableReader(Of Double)
	SS_ThermoRec_Delay_Reader = New NetworkVariableReader(Of Double)("\\192.168.10.2\SS_Real Time Variable Library\SS_ThermoRec_Delay")
	SS_ThermoRec_Delay_Reader.Connect()

	Private WithEvents SS_ThermoRec_Delay_Subscriber As NetworkVariableSubscriber(Of Double)
	SS_ThermoRec_Delay_Subscriber = New NetworkVariableSubscriber(Of Double)("\\192.168.10.2\SS_Real Time Variable Library\SS_ThermoRec_Delay")
	SS_ThermoRec_Delay_Subscriber.Connect()


	Private Sub SS_ThermoRec_Delay_Subscriber_Data_Updated(ByVal sender As System.Object, ByVal e As NationalInstruments.NetworkVariable.DataUpdatedEventArgs(Of Int32)) Handles SS_ThermoRec_Delay_Subscriber.DataUpdated
             SS_ThermoRec_Delay.Text = e.Data.GetValue
	End Sub
End Class

My problem is now I am still having trouble reading these pesky variables. I am trying the following code

Dim myVar As Double
myVar = SS_ThermoRec_Delay_Reader.ReadData

 I get the wiggly blue line under SS_ThermoRec_Delay_Reader.ReadData with the message ‘Value of type ‘NationalInstruments.NetworkVariableData(of Double)’ cannot be converted to ‘Double’.’

Anyone now how do a simple read? Any actual code would be appreciated

Thanks oh clever people

[nickb]

Hello -

Were you able to find the example I pointed you to?  It is actual code that shows exactly how to get the actual data from the object returned by ReadData.  Not only that, but there are many other examples there that should help you with the subscriber you're creating as well.

ReadData returns an object of type NetworkVariableData(of TValue).  To get the actual data of the variable, you must call GetValue on the NetworkVariableData(of TValue) object.

NickB

National Instruments