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Customer Solutions

TestStand Solves Test Executive Problems at TANDBERGTelevision

Author(s):

Dr. Michael Miles, Auric Solutions Ltd

Industry:

Consumer Goods

Product:

LabVIEW, NI TestStand

The Challenge:

Creating a new test executive that provides greater performance and flexibility while being easy and more economical to support, distribute, and upgrade.

The Solution:

Creating separate operator interfaces for production and diagnostic testing by customising the LabVIEW examples supplied with TestStand, and implementing an appropriate scheme for sequence execution handling, user login, and report generation by customising the TestStand process model and callback sequences.


Introduction
TANDBERG Television designs and manufactures professional-quality digital broadcast encoding and decoding products in Hamphire, U.K. Currently, they use a third-party LabVIEW test executive for core products, and their own LabVIEW test software for some board-level functional testing.
In a demanding manufacturing test environment, the existing diversity of test software has become increasingly difficult to support and adapt for an ever-increasing number of products and models. The current third-party test executive software has demonstrated a number of significant problems:

  • Uses outdated LabVIEW Test Executive 4.0
  • Requires high fee per license
  • Calls only LabVIEW 4.1 test modules
  • Runs only under Windows 95
  • Cannot link directly with LabVIEW for source code editing
  • Loads sequences into memory slowly for every execution
  • Includes inefficient and error-prone sequence editor
  • Features limited options for conditional execution and debugging

TANDBERG bases all other test software developed internally on an even older version of the LabVIEW test executive. They must also edit the software at the source code level and recompile it into an executable each time they add a new product or model.

Now, with the advent of National Instruments TestStand, TANDBERG Television can at least realise their goal of building around a common, off-the-shelf test executive. To this end, they contracted Auric Solutions to conduct all TestStand customisation and operator interface development. Auric Solutions customised the TestStand process model and callback sequences responsible for sequence execution, user login, and report generation, and created two separate operator interfaces - one for simple production testing, the other for advanced diagnostic testing. Auric conducted test development using the full development TestStand Sequence Editor.

The TestStand Process Model
With the TestStand process model, you can customise the sequence execution report generation. TANDBERG Television customised the process model to include:

  • Test Single UUT entry point sequence created to test a single Unit Under Test (UUT), and replaces the existing Test UUT sequence
  • Test reports saved into two locations (one for backup) under file names that include the UUT model number, serial number, and test result
  • Custom test report header including logo and additional information
  • Test certificate generation for good units

We changed user login to allow four password-protected user levels and a separate user name.

Subsequence Execution
For the more complex products from TANDBERG Television, a top-level sequence calls several subsequences that perform different tasks such as video, audio, and data testing. We can rerun each subsequence immediately on failure, error, or termination. To enhance subsequence execution, we took steps that include:

  • Creation of a new Sequence Call step type containing loop, pre, substep, and post-expressions
  • Detection of failure, error, or termination in the Cleanup group
  • Display of a dialogue window that prompts the operator to repeat, continue, or abort execution, or view the recent failures or errors

Simplified Operator Interface for Production Testing
The most common form of testing conducted at TANDBERG Television is final unit functional test. The key tasks performed by the operators are login, select the UUT (by model number), press the Start button, respond to manual prompts and tests during execution, and then print the test report and/or certificate. For this purpose, we created a very simplified interface that provides these functions and also displays run-time information, access to configuration options, and basic system and user information, including a help file. We use tabbed pages to keep the number of visible controls and indicators to a minimum. We can easily customise the colour, text, and internal actions of the six main function buttons on each page by editing a text file. The panel is 640 x 480 pixels in size and is clear even on the integrated 6.4 inch screen of the PXI-1020.

Advanced Operator Interface for Diagnostic Testing
We use the diagnostic interface, shown above, for fault isolation and repair purposes. It closely resembles the standard LabVIEW operator interface supplied with TestStand, but has the additional features of UUT model number selection for easy sequence retrieval, subsequence file opening, and useful debugging and execution functions accessible on the front panel as well as from the menu bar. The execution display window that appears during testing has changed only cosmetically from the original standard interface.

The Key Benefits
The primary benefits from changing to a TestStand test executive are a considerably more powerful, flexible, and economical software platform. Test operators benefit from the easy-to-use interfaces, and test development engineers benefit from a far more productive development environment. We have successfully addressed all shortcomings of the existing test software.

We can now further customise the operator interfaces, written using LabVIEW, as required by TANDBERG Television - they can now control, modify, and support all aspects of the new software, with full access to all LabVIEW source code. Because of the flexibility of TestStand, we can easily modify the execution behaviour of sequences and steps by editing variables and properties, rather than complex source code. With the upgrade to TestStand and the latest version of LabVIEW, we have formalised procedures for developing and releasing test programs (VIs) and sequences.

TANDBERG Television has gained the ability to create, duplicate, and distribute run-time installations at a substantially lower cost. Using National Instruments products directly, rather than through a third-party, means direct access to TestStand technical support and training, and a reliable upgrade path.

For more information, contact:

Dr. Miles

Auric Solutions Ltd

3 Panton Close

Emsworth, Hamphire PO10 7WX, U.K.

Tel/Fax: +44 (0) 1243 389 712

E-fax: +44 (0) 870 134 0365

E-mail info@auricsolutions.com

Web www.auricsolutions.com

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361730A-01.pdf

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