You should still be able to use VNC.
In your current AHMI project, just create a new form with simple controls for the room temperature.
Make sure this form's size and StartPosition properties are set the same as the MainForm.
Add the same Modbus driver to this form.
Add a standard button control to the MainForm and use it to show this new form.
This new form, when called, would be covering the MainForm so both of them could be running at the same time.
Something similar to the attached pictures.
For this experiment, I have used: ModbusTCP driver, standard buttons and a BasicLabel control on Page2.
This was the code behind these buttons:
Private currentTemp As Integer
Private Sub btnUP_Click(sender As Object, e As EventArgs) Handles btnUP.Click
currentTemp = CInt(ModbusTCPCom1.Read("40001"))
currentTemp += 1
ModbusTCPCom1.Write("40001", currentTemp)
End Sub
Private Sub btnDOWN_Click(sender As Object, e As EventArgs) Handles btnDOWN.Click
currentTemp = CInt(ModbusTCPCom1.Read("40001"))
currentTemp -= 1
ModbusTCPCom1.Write("40001", currentTemp)
End Sub
The BasicLabel had its PLCAddressValue set to "40001", a prefix "Temp: " and a suffix " °F".
