public static MeasurementResults MeasureSupplyIV(NIDCPower supplyHandle, string channelNames = "")
{
MeasurementResults results;
DCPowerMeasurementWhen measureMode = supplyHandle.Measurement.Configuration.MeasureWhen;
int samplesToFetch = supplyHandle.Outputs[channelNames].Measurement.RecordLength;
supplyHandle.Control.Initiate();
switch (measureMode)
{
case DCPowerMeasurementWhen.OnMeasureTrigger:
case DCPowerMeasurementWhen.AutomaticallyAfterSourceComplete:
DCPowerFetchResult fetchResult = supplyHandle.Measurement.Fetch(channelNames, new PrecisionTimeSpan(1), samplesToFetch);
results.Voltage_V = fetchResult.VoltageMeasurements;
results.Current_A = fetchResult.CurrentMeasurements;
break;
case DCPowerMeasurementWhen.OnDemand:
default:
DCPowerMeasureResult measureResult = supplyHandle.Measurement.Measure(channelNames);
results.Voltage_V = measureResult.VoltageMeasurements;
results.Current_A = measureResult.CurrentMeasurements;
break;
}
supplyHandle.Control.Abort();
//Calculate power
results.Power_W = new double[results.Voltage_V.Length];
for (int i = 0; i < results.Voltage_V.Length; i++)
{
results.Power_W[i] = results.Voltage_V[i] * results.Current_A[i];
}
return(results);
}
public static void TurnSupplyOnOrOff(NIDCPower supplyHandle, SupplyPowerMode powerMode, string channelNames = "")
{
switch (powerMode)
{
case SupplyPowerMode.PowerOn:
try
{
supplyHandle.Outputs[channelNames].Source.Output.Enabled = true;
//Initiate sourcing and wait until the output settles
supplyHandle.Control.Initiate();
supplyHandle.Events.SourceCompleteEvent.WaitForEvent(new PrecisionTimeSpan(1));
supplyHandle.Control.Abort();
//Despite the fact that we have aborted, sourcing continues until output is disabled.
//We abort because we do not wish to make measurements until requested.
}
catch (Exception e)
{
//Safety; disable output on any error
supplyHandle.Outputs[channelNames].Source.Output.Enabled = false;
supplyHandle.Control.Abort();
throw e;
}
break;
case SupplyPowerMode.PowerOff:
//To disable output, hardware needs to be in the running state.
//Initiate, disable, then abort.
supplyHandle.Control.Initiate();
supplyHandle.Outputs[channelNames].Source.Output.Enabled = false;
supplyHandle.Control.Abort();
break;
}
}
public static void ConfigureSupply(NIDCPower supplyHandle, SupplyConfiguration supplyConfig, string channelNames = "")
{
supplyHandle.Source.Mode = DCPowerSourceMode.SinglePoint;
supplyHandle.Outputs[channelNames].Source.Output.Function = supplyConfig.OutputFunction;
supplyHandle.Outputs[channelNames].Source.TransientResponse = supplyConfig.TransientResponseMode;
switch (supplyConfig.OutputFunction)
{
case DCPowerSourceOutputFunction.DCVoltage:
supplyHandle.Outputs[channelNames].Source.Voltage.CurrentLimitAutorange = DCPowerSourceCurrentLimitAutorange.On;
supplyHandle.Outputs[channelNames].Source.Voltage.VoltageLevelAutorange = DCPowerSourceVoltageLevelAutorange.On;
supplyHandle.Outputs[channelNames].Source.Voltage.VoltageLevel = supplyConfig.VoltageLevel_V;
supplyHandle.Outputs[channelNames].Source.Voltage.CurrentLimit = supplyConfig.CurrentLimit_A;
break;
case DCPowerSourceOutputFunction.DCCurrent:
supplyHandle.Outputs[channelNames].Source.Current.CurrentLevelAutorange = DCPowerSourceCurrentLevelAutorange.On;
supplyHandle.Outputs[channelNames].Source.Current.VoltageLimitAutorange = DCPowerSourceVoltageLimitAutorange.On;
supplyHandle.Outputs[channelNames].Source.Current.CurrentLevel = supplyConfig.CurrentLevel_A;
supplyHandle.Outputs[channelNames].Source.Current.VoltageLimit = supplyConfig.VoltageLimit_V;
break;
default:
throw new NotImplementedException("Pulse voltage/current is not implemented.");
}
if (supplyConfig.TransientResponseMode == DCPowerSourceTransientResponse.Custom)
{
switch (supplyConfig.OutputFunction)
{
case DCPowerSourceOutputFunction.DCVoltage:
supplyHandle.Outputs[channelNames].Source.CustomTransientResponse.Voltage.CompensationFrequency =
supplyConfig.CustomTransientConfig.CompensationFrequency;
supplyHandle.Outputs[channelNames].Source.CustomTransientResponse.Voltage.GainBandwidth =
supplyConfig.CustomTransientConfig.GainBandwidth;
supplyHandle.Outputs[channelNames].Source.CustomTransientResponse.Voltage.PoleZeroRatio =
supplyConfig.CustomTransientConfig.PoleZeroRatio;
break;
case DCPowerSourceOutputFunction.DCCurrent:
supplyHandle.Outputs[channelNames].Source.CustomTransientResponse.Current.CompensationFrequency =
supplyConfig.CustomTransientConfig.CompensationFrequency;
supplyHandle.Outputs[channelNames].Source.CustomTransientResponse.Current.GainBandwidth =
supplyConfig.CustomTransientConfig.GainBandwidth;
supplyHandle.Outputs[channelNames].Source.CustomTransientResponse.Current.PoleZeroRatio =
supplyConfig.CustomTransientConfig.PoleZeroRatio;
break;
}
}
}
public static void ConfigureMeasurement(NIDCPower supplyHandle, MeasurementConfiguration measConfig, string channelNames = "")
{
//On demand mode does not allow for multiple records to be acquired, so we need to validate the configuration given to this function.
if (measConfig.MeasureWhenMode == DCPowerMeasurementWhen.OnDemand &&
measConfig.MeasurementMode == MeasurementModeConfiguration.Record)
{
throw new ArgumentException("On Demand measurements can only be configured for a single measurement mode",
"MeasurementMode, MeasureWhenMode");
}
supplyHandle.Measurement.Configuration.MeasureWhen = measConfig.MeasureWhenMode;
supplyHandle.Measurement.Configuration.IsRecordLengthFinite = true;
if (measConfig.MeasureWhenMode == DCPowerMeasurementWhen.OnMeasureTrigger)
{
supplyHandle.Triggers.MeasureTrigger.DigitalEdge.Configure(
DCPowerDigitalEdgeMeasureTriggerInputTerminal.FromString(measConfig.MeasurementTriggerTerminal), DCPowerTriggerEdge.Rising);
}
supplyHandle.Outputs[channelNames].Measurement.Sense = measConfig.SenseMode;
int recordLength;
double apertureTime;
/*Single Point: Acquire a single measurement averaged over the duration of the Measurement Time
* Record: Acquire samples at the maximum sampling rate of the supply for the total duration of Measurement Time. */
switch (measConfig.MeasurementMode)
{
case MeasurementModeConfiguration.Record:
//Set the aperture time to the minimum value and read it back. This sets the "sample rate".
//Then, we calculate how many records we need to acquire at that sample rate to get the requested measurement time.
supplyHandle.Outputs[channelNames].Measurement.ApertureTime = 0;
double minApertureTime = supplyHandle.Outputs[channelNames].Measurement.ApertureTime; //dt (Seconds per Sample)
recordLength = (int)Math.Ceiling(measConfig.MeasurementTime_s / minApertureTime) + 1; // (Time_s)/(dt S/s) = #of samples
apertureTime = minApertureTime;
break;
case MeasurementModeConfiguration.SinglePoint:
default:
//Acquire a single record that is the average measurement over Measurement Time
apertureTime = measConfig.MeasurementTime_s;
recordLength = 1;
break;
}
supplyHandle.Outputs[channelNames].Measurement.ApertureTimeUnits = DCPowerMeasureApertureTimeUnits.Seconds;
supplyHandle.Outputs[channelNames].Measurement.ApertureTime = apertureTime;
supplyHandle.Outputs[channelNames].Measurement.RecordLength = recordLength;
}
static void Main()
{
string channelNames = "0";
NIDCPower dcPower = new NIDCPower("4139", channelNames, false);
// Configure instrument settings
SupplyConfiguration supplyConfig = SupplyConfiguration.GetDefault();
supplyConfig.OutputFunction = DCPowerSourceOutputFunction.DCVoltage;
supplyConfig.VoltageLevel_V = 3;
supplyConfig.CurrentLevel_A = 1;
ConfigureSupply(dcPower, supplyConfig, channelNames);
// Configure measurement related parameters
MeasurementConfiguration measConfig = new MeasurementConfiguration
{
MeasureWhenMode = DCPowerMeasurementWhen.AutomaticallyAfterSourceComplete,
SenseMode = DCPowerMeasurementSense.Remote,
// A MeasurementMode of "Record" acquires multiple smaples over the requested measurement
// time at the supply's maximum sampling rate. "Single Point" will take a single measurement
// over that duration and average the power and current results.
MeasurementMode = MeasurementModeConfiguration.Record,
MeasurementTime_s = 2e-3,
MeasurementTriggerTerminal = "PXI_Trig0"
};
ConfigureMeasurement(dcPower, measConfig, channelNames);
TurnSupplyOnOrOff(dcPower, SupplyPowerMode.PowerOn, channelNames);
MeasurementResults results = MeasureSupplyIV(dcPower, channelNames);
// Calculate the average of the acquired results
results = Utilities.CalculateAverageIV(results);
Console.WriteLine($"The average voltage measured was {results.Voltage_V[0]} with a current of {results.Current_A[0]}");
Console.WriteLine("Press any key to turn off the supply and exit the program.");
Console.ReadKey();
TurnSupplyOnOrOff(dcPower, SupplyPowerMode.PowerOff, channelNames);
CloseSupply(dcPower, channelNames);
}
/// <summary>
/// This example illustrates how to use the NI-DCPower APIs to configure the SMU and measure the results.
/// </summary>
static void Main()
{
string channelNames = "0";
NIDCPower dcPower = new NIDCPower("4139", channelNames, false);
// Configure instrument settings
SupplyConfiguration supplyConfig = SupplyConfiguration.GetDefault();
supplyConfig.OutputFunction = DCPowerSourceOutputFunction.DCVoltage;
supplyConfig.VoltageLevel_V = 3;
supplyConfig.CurrentLevel_A = 0.001;
supplyConfig.VoltageLimit_V = 3;
supplyConfig.CurrentLimit_A = 0.001;
ConfigureSupply(dcPower, supplyConfig, channelNames);
// Configure measurement related parameters
MeasurementConfiguration measConfig = MeasurementConfiguration.GetDefault();
measConfig.MeasureWhenMode = DCPowerMeasurementWhen.AutomaticallyAfterSourceComplete;
measConfig.MeasurementTime_s = 2e-3;
ConfigureMeasurement(dcPower, measConfig, channelNames);
TurnSupplyOnOrOff(dcPower, SupplyPowerMode.PowerOn, channelNames);
MeasurementResults results = MeasureSupplyIV(dcPower, channelNames);
// Calculate the average of the acquired results
results = Utilities.CalculateAverageIV(results);
Console.WriteLine($"The average voltage measured was {results.Voltage_V[0]} with a current of {results.Current_A[0]}");
Console.WriteLine("Press any key to turn off the supply and exit the program.");
Console.ReadKey();
TurnSupplyOnOrOff(dcPower, SupplyPowerMode.PowerOff, channelNames);
CloseSupply(dcPower);
}
static void Main()
{
string channelNames = "0";
NIDCPower dcPower = new NIDCPower("4139", channelNames, false);
SupplyConfiguration supplyConfig = new SupplyConfiguration();
supplyConfig.SetDefaults();
supplyConfig.OutputFunction = DCPowerSourceOutputFunction.DCVoltage;
supplyConfig.VoltageLevel_V = 3;
supplyConfig.CurrentLevel_A = 1;
supplyConfig.TransientResponseMode = DCPowerSourceTransientResponse.Fast;
ConfigureSupply(dcPower, supplyConfig, channelNames);
MeasurementConfiguration measConfig = new MeasurementConfiguration
{
MeasureWhenMode = DCPowerMeasurementWhen.AutomaticallyAfterSourceComplete,
SenseMode = DCPowerMeasurementSense.Remote,
MeasurementMode = MeasurementConfiguration.MeasurementModeConfiguration.SinglePoint,
MeasurementTime_s = 2e-3,
MeasurementTriggerTerminal = "PXI_Trig0"
};
ConfigureMeasurement(dcPower, measConfig, channelNames);
TurnSupplyOnOrOff(dcPower, SupplyPowerMode.PowerOn, channelNames);
MeasurementResults results = MeasureSupplyIV(dcPower, channelNames);
results = Utilities.CalculateAverageIV(results, 3);
TurnSupplyOnOrOff(dcPower, SupplyPowerMode.PowerOff, channelNames);
CloseSupply(dcPower, channelNames);
}
public static void CloseSupply(NIDCPower supplyHandle, string channelNames = "")
{
//Quickly ensures all outputs are disabled and resets the device
supplyHandle.Utility.Disable();
supplyHandle.Close();
}
