Actions
Forum Thread Details
  • State Not Answered
  • Replies 5 replies
  • Subscribers 480 subscribers
  • Views 526 views
  • Users 0 members are here
Related

Embedded Design Testing

Former Member

Hi,

 

I hope this discussion is in the right group but here goes...

 

I have recently started using Perl on my PC to auotmattically test serial features of my embedded designs. It works really well, but the designs do not just have serial I/O, but have Analogue and Digital I/O, which means I cannot test the whole design.

 

Thinking about solving the problem, I though the same Perl test program could also talk to a 'Smart' Test Harness in addition to the serial communication direct to the embedded design under test. It would be a good project to do, a micro with I/O interface circuits, some kind of serial software interface that would allow for control the I/O. But I do not have time, and I am sure other people do this kind think.

 

I know about the NI equipment and Labview, but that would be overkill for my applications.

 

What do others in this group use for their automated testing of their designs? Is there an a relative inexpensive device that would fit my needs?

  • 0

    Hello Ross,

     

    You don't specify you digital and analogue interfaces in enough detail to give more than a general answer.

     

    I usually find that custom made test boards are necessary for all but the most simple or standard interfaces. If you are not too bothered about speed than you can sometimes use a cheap (TTi ? or even cheaper Far Eastern) programmable power supply to stimulate inputs and a DMM for measuring. You usually end up needing multiplexers on both.

     

    There are plenty of cheap interfaces about (eg LabJack U12 for £95) gives you some analogue and digital IO but the resolution and speed are nothing special.

     

    Almost anything will be cheaper (to buy) than NI and LabView but they claim it pays for itself in speed of development and performance - they do have some LabJack like parts which are not insanely pricey which might be worth checking if you already use their software.

     

    Michael Kellett

  • 0

    You may want to consider off the shelf I/O modules used for PLC's and other factory automation.  You get to pick and choose your I/O in a modular format.   There are DIN rail mount modules, and plug-in carrier modules.  Take a look at:

     

    http://www.newark.com/process-control-timers-counters_accessories

  • 0

    Hi Ross,

     

    Before you can adequately test your device, you need to define your testing requirements.  I cannot tell you about the number of projects I was tossed into where they only budgeted the development effort and not the test effort.  If you are going to do quality work, you need to assess and budget for both.

     

    In many respects, your testing rig will need more work than your device.  Why?  Because you have to verify and validate your test rig before you can adequately test your device.  I know it sounds a little wierd, but when you sit down and look at the problem, you will find that your testing rig might well be more expensive to build than your actual device.

     

    Once you document what your test rig needs to include, then you can look for off the shelf components that fit your needs.  Once you reach a stable configuration, you then need to assess what additional testing items you need to verify that your test rig works.

     

    I could go on, but I think I have made my point about the importance of understanding your testing needs and the care you must take to do it right.

    After all, if your test rig is faulty, then your device will contain errors as well.  Proper testing is just as important as the development process.

     

    If you spend the time in testing, you will end up with happy customers.  Otherwise, you may find that they seek out others to do their next job.

     

    Just a thought,

    DAB

  • 0

    Thanks Michael & DAB for your replys,

     

    The LabJack looks like it is what I am after, and there is even a Perl module for it image

     

    DAB:

     

    We already have a number of test rigs for production testing and yes it does take a lot longer than one expects to make one. Also the importance of having a golden device to test the test rig against.

     

    I was after something more for software acceptance testing and in particular specific application testing.  So having something that is more versatile is an advantage.

     

    Sorry I was not more clear in my initial question.

     

    Ross

  • 0 in reply to Former Member

    Hi Ross,

     

    No problem.  As you can tell from my post, testing issues is one of my hot buttons.

    You are correct that you can take some off the shelf hardware and build up some very simple testing generators.  I have done this type of simple testing on a lot of devices.  As long as you just need some simple signals to trigger events, it is perfectly adequate.

     

    It would be nice if someone could start an open hardware testing rig with simple outputs.  You could easily do most of these with an Arduino or other inexpensive MCU.  All you need is to build up some hardware circuits to widen the range of interfaces you need to drive and you would have a simple and easy to program test generator.

     

    Just a thought,

    DAB