Latest IVI Class Step Types in TestStand

[David_Jackson]

IVI instrument classes have recently been defined for RF Signal Generator, Spectrum Analyzer and Power Meter. There are IVI drivers for these classes available for download from the Instrument Driver network. However, TestStand3 does no contain step types for accessing these drivers. Does anyone know when NI plans to add support for these to TestStand? Has anyone created step types for these classes, or have an example of how to do this?

[Scott_Richardson]

David -
You are correct in that TestStand 3.0 does not include any new step types for the newest IVI class drivers. NI still supports and contributes to the IVI Foundation and TestStand may add the new IVI class step types in the future but such step types are not currently in development. One option that you may want to consider is to use your preferred development environment, such as LabVIEW, CVI or Visual Studio, to write code modules that talk directly to the IVI class layer. Also, there is an application note on creating configurable step types if you are interested in developing own IVI step types for these classes,
Creating Configurable Test S
teps in TestStand. Lastly, the source code for the IVI step types is available so additional step types for the other classes could be developed separately if written in MSVB, but the underlying code that talks to the new class layers would have to be developed from the ground up.

Hope this helps.
Scott Richardson (NI)

[David_Jackson]

Thanks for your advice Scott. It would be good to be able to create the additional step types and I have looked at the source code in the \Components\NI\StepTypes\IVISteps directory to see what is involved. I could create the VB class modules, forms and code but am unsure how to build the dll. There are several VB projects (TsIviStep and TSIviSFP) and also a C++ workspace (TsIviStepTypes). The workspace seems to be the only way to build the TsIviStepType.dll used as the automation server. I'm wondering are there any examples (or tutorials) available on how to build this, or alternatively any wizards that would help? I can't find any information on the NI web site about this as it is difficult to know how o go about this without some advice.

[Scott_Richardson]

David -
There is no documentation on the low-level workings of the TestStand IVI step types. As with many of the step types that have source code, it is available as examples of developing a step type in various languages.

The additional work to add the a new class to the TestStand IVI step types is not small, that is why to date we have not done it. The amount of work could be divided into the following areas:
* Update the TsIviStepTypes to add the new class to the enumeration.
* Create the new step type definition (subproperty structure) based on the IVI spec.
* Upcate the TSIviStep and TSIviSFP code to allow you to edit and perform the work to process the expressions and initiate the various IVI class operations.
* Add low level
IVI class layer logic to talk to the IVI class driver. This piece was previously done in a VB ActiveX control written by the Measurement Studio group in NI.

The last two items are the biggest and they would take some time. That is why I was suggesting creating specific Action steps that call into custom code modules to talk to IVI directly, that is, no edit dialog box, no SFP, etc.

Scott Richardson (NI)

[David_Jackson]

Thanks again Scott. I was beginning to grasp the enormity of the task - thanks for putting it in perspective. I like the TestStand IVI step types as they provide a graphical interface to instrumentation, as well as the ability to control instruments interactively. I guess the new IVI step types will be available in the future? In the meantime we shall probably use the IVI step types currently available with a combination of custom step types that we'll create to call the other classes as you suggest. Is there anyway of being kept up to date on NI's progress in developing the new IVI Step Types?

[Scott_Richardson]

David -
As with many products that we develop, we typically do not discuss if and when specific features will be available. It keeps us developers from getting into trouble. Our beta programs offer the best option for an early look at new features. Best of luck with your applications.

Sincerely,
Scott Richardson (NI)