//==============================================================================================
/// <summary>
/// calculates the max scan rate based on the method type calculation and channel count
/// </summary>
/// <param name="device">the daq device</param>
/// <returns>max rate base on current configuration</returns>
//==============================================================================================
public static double CalculateMaxAiScanRate(DaqDevice device)
{
double deviceMaxRate;
double deviceMaxThruput;
double deviceMaxBurstRate;
double deviceMaxBurstThruput;
double maxRate = 0;
int channelCount = 0;
string xferMode;
string sampleRateCalculationMethod;
string msg;
string textResponse;
ErrorCodes msgError;
// test if the queue component is supported by the device...
msgError = device.SendMessageDirect(Messages.AIQUEUE_COUNT_QUERY);
if (msgError == ErrorCodes.NoErrors)
{
// get the response...
textResponse = MessageTranslator.GetPropertyValue(device.DriverInterface.ReadStringDirect());
// convert to int...
if (!PlatformParser.TryParse(textResponse, out channelCount))
{
// alert the developer...
System.Diagnostics.Debug.Assert(false, "RateCalulator.CalculateMaxAiScanRate: The channel count could not be parsed");
// use a default value...
channelCount = 1;
}
}
if (channelCount == 0)
{
int lowChannel;
int highChannel;
// get the low channel number...
device.SendMessageDirect(Messages.AISCAN_LOWCHAN_QUERY);
// get the reponse...
textResponse = MessageTranslator.GetPropertyValue(device.DriverInterface.ReadStringDirect());
if (!PlatformParser.TryParse(textResponse, out lowChannel))
{
// alert the developer...
System.Diagnostics.Debug.Assert(false, "RateCalulator.CalculateMaxAiScanRate: The low channel could not be parsed");
// use a default value...
lowChannel = 0;
}
// get the high channel number...
device.SendMessageDirect(Messages.AISCAN_HIGHCHAN_QUERY);
// get the reponse...
textResponse = MessageTranslator.GetPropertyValue(device.DriverInterface.ReadStringDirect());
if (!PlatformParser.TryParse(textResponse, out highChannel))
{
// alert the developer...
System.Diagnostics.Debug.Assert(false, "RateCalulator.CalculateMaxAiScanRate: The high channel could not be parsed");
// use a default value...
highChannel = 0;
}
channelCount = highChannel - lowChannel + 1;
}
// get the transfer mode...
device.SendMessageDirect(Messages.AISCAN_XFRMODE_QUERY);
// get the response...
xferMode = MessageTranslator.GetPropertyValue(device.DriverInterface.ReadStringDirect());
// get the scan rate calculation method...
sampleRateCalculationMethod = device.GetDevCapsString("AISCAN:SCANRATECALC", true);
switch (sampleRateCalculationMethod)
{
// multiplexed...
case (PropertyValues.METHOD1):
{
if (xferMode == PropertyValues.BURSTIO)
{
// get the max burst rate...
deviceMaxBurstRate = device.GetDevCapsValue("AISCAN:MAXBURSTRATE");
// calculate the max rate...
if (channelCount > 0)
{
maxRate = deviceMaxBurstRate / channelCount;
}
else
{
maxRate = deviceMaxBurstRate;
}
}
else
{
// get the max scan rate...
deviceMaxRate = device.GetDevCapsValue("AISCAN:MAXSCANRATE");
// calculate the max rate...
if (channelCount > 0)
{
maxRate = deviceMaxRate / channelCount;
}
else
{
maxRate = deviceMaxRate;
}
}
break;
}
// simultaneous...
case (PropertyValues.METHOD2):
{
if (xferMode == PropertyValues.BURSTIO)
{
// get the max burst thruput...
deviceMaxBurstThruput = device.GetDevCapsValue("AISCAN:MAXBURSTTHRUPUT");
// get the max burst rate...
deviceMaxBurstRate = device.GetDevCapsValue("AISCAN:MAXBURSTRATE");
// calculate the max rate...
if (channelCount > 0)
{
maxRate = Math.Min(deviceMaxBurstThruput / channelCount, deviceMaxBurstRate);
}
else
{
maxRate = deviceMaxBurstThruput;
}
}
else
{
// get the max scan thruput...
deviceMaxThruput = device.GetDevCapsValue("AISCAN:MAXSCANTHRUPUT");
// get the max scan rate...
deviceMaxRate = device.GetDevCapsValue("AISCAN:MAXSCANRATE");
// calculate the max rate...
if (channelCount > 0)
{
maxRate = Math.Min(deviceMaxThruput / channelCount, deviceMaxRate);
}
else
{
maxRate = deviceMaxThruput;
}
}
break;
}
// multiplexed - 2408 series
case (PropertyValues.METHOD3):
{
double sum = 0.0;
double dataRate;
for (int i = 0; i < channelCount; i++)
{
msg = Messages.AIQUEUE_DATARATE_QUERY;
msg = msg.Replace("*", i.ToString());
device.SendMessageDirect(msg);
textResponse = MessageTranslator.GetPropertyValue(device.DriverInterface.ReadStringDirect());
if (PlatformParser.TryParse(textResponse, out dataRate))
{
// get the data rate value...
dataRate = device.SendMessage(msg).ToValue();
}
else
{
// alert the developer...
System.Diagnostics.Debug.Assert(false, "RateCalulator.CalculateMaxAiScanRate: The data rate could not be parsed");
// use a default value...
dataRate = 100;
}
sum += (1.0 / dataRate) + 0.000640;
}
maxRate = 1.0 / sum;
break;
}
default:
{
System.Diagnostics.Debug.Assert(false, String.Format("{0} is not supported by GetMaxAiScanRate()", sampleRateCalculationMethod));
break;
}
}
// truncate to two decimal digits...
#if WindowsCE
maxRate = (double)((int)maxRate);
#else
maxRate = Math.Truncate(maxRate);
#endif
// save the caculated rate...
device.Ai.CalculatedMaxSampleRate = maxRate;
// query the rate...
device.SendMessageDirect(Messages.AISCAN_RATE_QUERY);
// read the current value...
string response = MessageTranslator.GetPropertyValue(device.DriverInterface.ReadStringDirect());
// try and convert the value...
double currentRate = Double.NaN;
// parse the value...
if (PlatformParser.TryParse(response, out currentRate))
{
// construct the set rate message...
msg = Messages.AISCAN_RATE;
// inject the max rate value...
msg = msg.Replace("#", maxRate.ToString());
// set the rate...
device.SendMessageDirect(msg);
// query the rate...
device.SendMessageDirect(Messages.AISCAN_RATE_QUERY);
// read the value...
response = MessageTranslator.GetPropertyValue(device.DriverInterface.ReadStringDirect());
double actualMaxRate = Double.NaN;
if (PlatformParser.TryParse(response, out actualMaxRate))
{
double returnedRate = actualMaxRate;
// was the value returned rounded up?...
while (returnedRate > maxRate)
{
// decrease it...
actualMaxRate = Math.Round(actualMaxRate - device.Ai.RateCalculatorDecrementCount, 2);
msg = Messages.AISCAN_RATE;
msg = msg.Replace("#", actualMaxRate.ToString());
// update the rate...
device.SendMessageDirect(msg);
// query the rate...
device.SendMessageDirect(Messages.AISCAN_RATE_QUERY);
// read the value...
response = MessageTranslator.GetPropertyValue(device.DriverInterface.ReadStringDirect());
if (!PlatformParser.TryParse(response, out returnedRate))
{
// alert developers...
System.Diagnostics.Debug.Assert(!Double.IsNaN(currentRate), "RateCalculator.GetMaxAiScanRate: The max rate could not be converted to a double");
}
}
// set the actual max rate...
maxRate = actualMaxRate;
// save the actual max rate...
device.Ai.ActualDeviceMaxSampleRate = maxRate;
// restore the rate...
msg = Messages.AISCAN_RATE;
// is it the device max rate?...
if (currentRate == device.Ai.ActualDeviceMaxSampleRate)
{
// use the calculated max rate...
msg = msg.Replace("#", device.Ai.CalculatedMaxSampleRate.ToString());
}
else
{
// use the current rate...
msg = msg.Replace("#", currentRate.ToString());
}
// set the rate...
device.SendMessageDirect(msg);
}
else
{
// alert developers...
System.Diagnostics.Debug.Assert(!Double.IsNaN(currentRate), "RateCalculator.GetMaxAiScanRate: The max rate could not be converted to a double");
}
}
else
{
// alert developers...
System.Diagnostics.Debug.Assert(!Double.IsNaN(currentRate), "RateCalculator.GetMaxAiScanRate: The rate could not be converted to a double");
}
return maxRate;
}
//===================================================================================================
/// <summary>
/// Calculates the delta t between samples per channel
/// </summary>
/// <param name="device"></param>
/// <returns></returns>
//===================================================================================================
public static double GetSampleDt(DaqDevice device)
{
double sampleRate;
int channelCount = 0;
if (device.SendMessage(Messages.AISCAN_STATUS_QUERY).ToString().Contains(PropertyValues.IDLE))
{
try
{
// test if the queue component is supported by the device...
channelCount = (int)device.SendMessage(Messages.AIQUEUE_COUNT_QUERY).ToValue();
ErrorCodes e = device.SendMessageDirect("XYZ");
}
catch (Exception)
{
// no queue component support...
int lowChannel = (int)device.SendMessage(Messages.AISCAN_LOWCHAN_QUERY).ToValue();
int highChannel = (int)device.SendMessage(Messages.AISCAN_HIGHCHAN_QUERY).ToValue();
channelCount = highChannel - lowChannel + 1;
}
// get the current sample rate setting...
sampleRate = device.SendMessage(Messages.AISCAN_RATE_QUERY).ToValue();
// calculate the sample dt...
m_sampleDt = 1.0 / sampleRate;
}
return m_sampleDt;
}
//=============================================================================
/// <summary>
/// Gets setup parameters
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
//=============================================================================
private void OnSetupButtonClicked(object sender, EventArgs e)
{
LogData = false;
LogFile = String.Empty;
Notes = String.Empty;
SetupDialog.ShowDialog();
if (SetupDialog.DaqDevice != null)
{
if (SetupDialog.SupportsTemperature)
{
string msg;
DaqDevice = SetupDialog.DaqDevice;
DeviceName = SetupDialog.DeviceName.Split(new char[] { ':' })[0];
DeviceSerno = SetupDialog.DeviceName.Split(new char[] { ':' })[2];
TcType = SetupDialog.TcType;
Channel = SetupDialog.Channel;
// try setting the channel mode if it's programmable
try
{
msg = "AI{*}:CHMODE=#";
msg = msg.Replace("*", Channel);
msg = msg.Replace("#", SetupDialog.ChannelMode);
DaqDevice.SendMessage(msg);
}
catch (Exception)
{
try
{
msg = "AI:CHMODE=#";
msg = msg.Replace("#", SetupDialog.ChannelMode);
DaqDevice.SendMessage(msg);
}
catch (Exception)
{
}
}
// set the sensor type for the selected channel
msg = "AI{*}:SENSOR=TC/#";
msg = msg.Replace("*", Channel);
msg = msg.Replace("#", TcType);
SendDeviceMessage(msg);
SelectedUnits = SetupDialog.Units;
SamplePeriod = SetupDialog.SamplePeriod;
LogData = SetupDialog.LogData;
Notes = SetupDialog.Description;
yLabel.Text = SelectedUnits;
if (LogData)
{
LogFile = SetupDialog.LogFile;
Notes = SetupDialog.Description;
}
startButton.Enabled = true;
stopButton.Enabled = true;
}
}
}