FEATURE TEST & MEASUREMENT Oscilloscope automation advanced by .NET
Joe Evangelista at Keysight Technologies illustrates how .NET technology implemented by an oscilloscope vendor in their digital transmitter compliance test product is offering valuable measurement science that is easily accessible via the automation code
A
n oscilloscope vendor incorporating more measurement science into their
product offerings may be an active member of standards bodies such as PCI Express, SATA, JEDEC and the USB-IF. The active participation in these standards enables vendors to help define test specifications which are intended to ensure interoperability of devices supporting a particular standard. Once the test requirements are defined, the oscilloscope vendor can implement the various measurements defined per the standard and add it to their oscilloscope software offering. Users can now access a standard test suite of software enabled by .NET technology for qualifying their device compliance to a particular data communication standard. The software platform should also enable
full remote control access. The oscilloscope vendor assumes responsibility for interpreting the test specifications of a standard, and is tasked with developing the measurement software suite and providing technical support. Figure 1 is an example of a software suite that exposes the available tests defined in the DDR4 computer memory standard. The customer selects the tests of interest and the appropriate measurements and algorithms are implemented by the oscilloscope vendor’s automated software. It is important to look for an oscilloscope vendor that provides the same look and feel for all their standards-based measurement software. A DDR4 software test package should have the same look and feel as one for PCI Express thus increasing the efficiency and productivity of the end user. A complete software suite for testing to a data communication standard should produce data in easily readable form such as the example in Figure 2. An HTML report including screen shots where applicable for all tests executed with pass/fail/margin information creates great value to the customer and engineering teams. A software framework built on .NET technology allows the automation engineer to access all the features in the oscilloscope vendor’s measurement software designed for a data communications standard. Moreover, it enables engineers to hook into asynchronous runtime events in order to integrate automation of supporting instruments, for example by programmatically responding to the message prompt, “Change the power supply
14 JULY/AUGUST 2015 | ELECTRONICS
pFW.Remote") from
Keysight.Infiniium.AppFW.Remote import *
output to 1V and click ‘OK’ to continue”. These events no longer need time- consuming manual intervention. The following example in Python shows
how the use of a .NET assembly can provide a perfect level of abstraction to the automation engineer without burdening the engineer with the details of setting up test conditions, managing test flow and ultimately measured data management.
Figure 1:
Test Selection Menu from a DDR4 Memory Device Compliance Software Suite
Required to connect to the oscilloscope via an Ethernet connection for access to the methods and proprieties exposed in the .NET assemblies. remoteObj =
RemoteAteUtilities.GetRemoteAte("192.1 68.1.107") remoteApp = IRemoteAte(remoteObj) The object named remoteApp can now access all the features of the particular measurement software suite for the selected data communication standard as if it was being done interactively from the GUI of the test suite. The following illustrates the code needed by the automation engineer to create a new project analogous to performing File- >New Project from the GUI of the measurement software suite.
remoteApp.NewProject(True) A critical piece of documentation for
efficient use of the .NET assembly is a complete and up-to-date help file from the oscilloscope vendor. An excerpt from a help file below defines what options are available when creating an HTML report. The options are implemented in the above Python example. ExportHtmlOptions PropertiesKeysight DigitalTestApps Remote Interface for .NET The ExportHtmlOptions type exposes the following members. Properties Name Description BasePath
Path to save report to. A subdirectory named after ReportName will be created. OverwriteExisting
Set this property to true to overwrite an existing report with the same name at the specified location. ReportName Name of report to generate. Better still are in-GUI tips, which answer questions such as, “Which automation command clicks this checkbox?”. Customers will continue to look to
Microsoft’s Common Language Runtime
engine enables easy loading of a .NET assembly from a variety of programming languages such as Visual Basic, C#, C++ as well as graphical programming languages such as Keysight’s VeePro and NI’s LabWindows and LabView. In
addition.NET technology can be extended to cover a broad range of automation tasks including controlling environmental chambers, communication to the device under test, switch matrices and of course other instruments beyond an oscilloscope. import clr
clr.AddReference("
Keysight.Infiniium.Ap
Figure 2:
Sample HTML report generated by DDR4 Memory Device Compliance Software Suite
oscilloscope vendors to provide an oscilloscope as a measurement system which includes connectivity solutions to their device such as probes, measurement software suites that address the various data communication standards, and a high level abstraction of the measurement software suite - thus enabling automation engineers to easily control the execution of the measurement software suite from their internal automation software.
Keysight Technologies
www.keysight.com 0800 1189 276855
/ ELECTRONICS
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