How do I a pulse measurement using an SMU?

[markshancock]

I have a PXIe-4139 and I want to make a pulsed current measurement.

I will be creating a program to run this test and I will be using nidcpower to interface to the SMU (I have version 20.7)/

I found several documents describing how to configure the various parameters but I don't see how to initiate the pulse.

I want to do this under SW control not using a HW trigger.

[santo_13]

In that case, just the Initiate should fire the pulse.

[markshancock]

Cool, I will try that.

Thanks

[markshancock]

I think I found it.  In order to generate a pulse, you need to use the new (v 21.0) Pulse Trigger

[markshancock]

I configured the SW pulse trigger and I am still not able to generate a pulst

[OmarMejia]

Hello markshancock,

Have you tried using one of the examples installed with NI-DCPower?

https://www.ni.com/docs/en-US/bundle/ni-dcpower-21.0-help/page/ni_dc_power_supplies_help/ni-dcpower_...

C:\Users\Public\Documents\National Instruments\NI-DCPower\Examples\DotNET 4.5\Pulsing\Single point\Pulse Current\cs

our pulse current examples should have what you need to get started, if not, please do reach out again.

thanks,

[markshancock]

The driver I am updating is older and uses the .c api.  Is there an example for creating a pulse using the c api?
One big question I have is the difference between the two sets of methods (one with and one without "WithChannels")
Ex: 

niDCPower_ConfigureSourceMode(ViSession vi,ViInt32 sourceMode);

niDCPower_ConfigureSourceModeWithChannels(ViSession vi,ViConstString channelName,ViInt32 sourceMode);

The 1.6 v did not have the WithChannels methods (except for InitializeWithChannels).

[kirsch]

There is no C example, but the ADE bindings for all the other languages map very very well to C, you should be able to translate it.

> One big question I have is the difference between the two sets of methods (one with and one without "WithChannels")

NI-DCPower's overall operating model was changed recently. You opt-in by opening your session using niDCPower_InitializeWithIndependentChannels(). This is the default in LabVIEW and the preferred way of using NI-DCPower.

What does "Independent Channels" give you? The ability to control the state of the channels independently when in a multi-channel session. For example, instead of calling niDCPower_Initiate(vi) which acts on all the channels in the session, you can call niDCPower_InitiateWithChannels(vi, "0-3") to initiate that subset. It also allows multi-intrument sessions - that is, sessions that span channels across multiple SMUs.

I hope that explains the difference.

[markshancock]

@kirsch,

      The SW example I used was C# PulseVoltage.

dcPowerSession.Source.Mode = DCPowerSourceMode.SinglePoint;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.Output.Function = DCPowerSourceOutputFunction.PulseVoltage;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.PulseVoltage.VoltageLevel = PulseVoltageLevel;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.PulseVoltage.VoltageLevelRange = PulseVoltageLevelRange;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.PulseVoltage.BiasCurrentLimit = BiasCurrentLimit;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.PulseVoltage.CurrentLimit = PulseCurrentLimit;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.PulseVoltage.CurrentLimitRange = PulseCurrentLimitRange;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.PulseVoltage.BiasVoltageLevel = BiasVoltageLevel;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.PulseOnTime = PulseOnTime;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.PulseOffTime = PulseOffTime;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.PulseBiasDelay = PulseBiasDelay;
dcPowerSession.Outputs[FullyQualifiedChannelName].Source.SourceDelay = SourceDelay;
dcPowerSession.Outputs[FullyQualifiedChannelName].Measurement.ConfigureApertureTime(ApertureTime, DCPowerMeasureApertureTimeUnits.Seconds);
//Initiate the device to start generation and acquisition.
dcPowerSession.Control.Initiate();

I added log statements to record the calls I am making to niDCPower_32.dll

16:50:01,837 Abort[0], Rtn=0
16:50:01,837 Set property[0,OutputFunction] to value=1049, Rtn=0
16:50:01,867 Get property[0,OutputFunction] returned value=1049, Rtn=0
16:50:01,887 ConfigPulseVoltageRange[0]=3.6, Rtn=0
16:50:01,897 ConfigPulseVoltage[0]=3, Rtn=0
16:50:01,917 ConfigPulseBiasCurrentLimit[0]=0.01, Rtn=0
16:50:01,937 ConfigPulseCurrentLimitRange[0]=0.1, Rtn=0
16:50:01,957 ConfigPulseCurrentLimit[0]=0.01, Rtn=0
16:50:01,977 ConfigPulseBiasVoltage[0]=0, Rtn=0
16:50:01,997 Set property[0,PulseOnTime] to value=0.1, Rtn=0
16:50:02,017 Set property[0,PulseOffTime] to value=0.1, Rtn=0
16:50:02,037 Set property[0,PulseBiasDelay] to value=0.0001, Rtn=0
16:50:02,057 ConfigSoftwarePulseTrigger[0], Rtn=0
16:50:04,088 Set property[0,OutputEnabled] to value=True, Rtn=0
16:50:04,088 Set property[0,OutputConnected] to value=True, Rtn=0
16:50:04,098 Initiate[0], Rtn=0
16:50:04,138 SendSoftwareTrigger=1053, Rtn=0
16:50:05,339 Abort[0], Rtn=0

The [0] indicates the call is made on channel '0' using a "...WithChannels" call.  Ex:

public int Initiate(string Channel)
{
   int pInvokeResult = PInvoke.InitiateWithChannels(this._handle, Channel);
   log.DebugFormat("Initiate[{0}], Rtn={1}", Channel, pInvokeResult);
   PInvoke.TestForError(this._handle, pInvokeResult);
   return pInvokeResult;
}

I have the SMU attached to a PXIe-5160 and I am capturing the output waveform.

To confirm the setup, I generated a pulse in SW by running the SMU in VoltageMode and changing the output voltage.

That worked fine so I know the setup is correct.

Note: I setup the digitizer and start the acquisition in the gap around 16:50:03 

When I run my pulse code, this is what I get. No pulse

I don't see much difference between the calls I make and my inference from the C# example

[markshancock]

Note: I tried the code without the ConfigSoftwarePulseTrigger and SendSoftwareTrigger and I get the same result.