public SampleMaster3000ViewModel(string niDeviceAddresss)
        {
            try
            {
                _niInterface = new NiInterface(niDeviceAddresss, Properties.Settings.Default.SampleFrequency, 10);
                _niInterface.CompletedSamples += _niInterface_CompletedSamples;

                _readValueTimer = new DispatcherTimer(DispatcherPriority.Normal, Application.Current.Dispatcher) { Interval = TimeSpan.FromMilliseconds(100) };
                _readValueTimer.Tick += _readValueTimer_Tick;
                _readValueTimer.Start();

                DeviceStarted = Visibility.Visible;

                _syncCtx = SynchronizationContext.Current;

                Directory.CreateDirectory(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) +
                                          "\\KCF Technologies\\Gauss Master");

                SampleFrequency = Properties.Settings.Default.SampleFrequency.ToString();
            }
            catch (Exception ex)
            {
                MainWindow.ShowError(ex.Message, true);
            }
        }
        public GaussMeter3000ViewModel(string comPort, string niDeviceAddresss)
        {
            try
            {
                _sc = new GaussSerialComms(comPort);
                _sc.StringReceived += _sc_StringReceived;
                _sc.DeviceStarted += _sc_DeviceStarted;
                _sc.ChangedChannel += _sc_ChangedChannel;

                _niInterface = new NiInterface(niDeviceAddresss, Convert.ToInt32(Properties.Settings.Default.SampleFrequency), 2);
                _niInterface.CompletedSamples += _niInterface_CompletedSamples;

                _currentChannel = GaussMeterChannelEnum.Unknown;

                DeviceStarted = Visibility.Hidden;
                ResetDevice = Visibility.Visible;

                _syncCtx = SynchronizationContext.Current;

                Directory.CreateDirectory(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) +
                                          "\\KCF Technologies\\Gauss Master");

                SampleFrequency = Properties.Settings.Default.SampleFrequency;
            }
            catch (Exception ex)
            {
                MainWindow.ShowError(ex.Message, true);
            }
        }