Welcome to our
Before we look
at our Monthly Category discussion, we would like to introduce
Centec, a German company that may very well have products that
will be useful to many NZ companies. Centec fits into both the
product and advanced industrial solutions categories.
next month on Centec
Also an apology
for missing out some DAQ software companies last month. These
other companies are on the bottom of the Logo Matrix above, namely
Azeotech and DasyLab.
month our Product Category focus is:-
PXI, cPCI, VXI, LXI
Software Configurable Instruments
Virtual Instruments from DAQ
DAQ in Test Systems
We have also
Panel + Bench + Handheld Instruments
A total of 29
companies with a huge range of products.
We don't have (Keysight) Agilent
or Tek, but we do have Rigol, GW Instek, Atten, Array, Kinetic
Systems and several more.
Almost all of these companies
produce GPIB, Ethernet or USB Traditional Bench or Rack Instruments
with Instrument drivers software.
PXI, cPCI, VXi,
Back in the late 80s and early
90s these newer technologies arose as a way to build chassis
with many "Instruments on a Card" in a 19" racks.
The idea was that to have a bunch
of Traditional instruments in a Test system was highly redundant,
as they all had their own cases and chasiss, power supplies,
very expensive user front panels with a load of mechanical or
electrical controls and a display.
If all of this redundant stuff
was removed, and only the instrument electronics was kept and
mounted in a single PCB on a standard bus like PXI, huge savings
in space, electricity, costs could be made and compact very specific
test systems down into a multi slot 19' chassis.
"Instruments on a Card"
in PXI format was Test Industry's answert.
The chassis would house multiple
PXI Instruments on a Card and be linked to a Test Computer which
would offer the user interface and the display to all the individual
PXI Instrumentsd. By adding a screen or several screens on the
PC, a composite compact Test instrument could be built, called
a Test Set.
Well it sort of worked, but costs
didn't come down but size of kit did and speed of tests went
up, usually. So big gains for some types of tests.
So choosing between Traditional
and Instruments on a cards is now an essential part of the design
and specing stages for any Test.
This the lowest leave of Test
Instrument and in many cases will suffice. Basically a DAQ product
is used to collect analog or digital data and all the Instrument
like features required are mimiced in software. It works well if it meets requirement
and is very low cost.
Note NI and MCC both have software
to turn low cost DAQ into Strip charts, Scopes, Function Generators
etc with various levels of ability.
I would have expected heaps of
these by now, that is using Smart Phones and Tablets to build
Oscium were first with Spectral
2.4GHZ Instruments. A small plug in instrument front end is conected
to the smart phone's USB port.
MCC and Eagle both have Bluetooth
DAQ. NI is flirting with
WiFi DAQ, but not instruments yet.
The difficulty it seems is in
the software rather than the devices. Building virtual test instruments
in a Smart Phone or a Tablet requires a lot of expertise.
We have included Sheldon once
again. Read their specs for DAQ and DSP. You can build very high
end MHZ spectral instruments on PCi, PCIe or on the end of an
Measurement Studio from NI.
Also VB.net, C, C++, C# tools
Most would use
LabVIEW or Measurement Studio as a start point as they come with
a huge array of instrument drivers for traditional and PXI/VXI
instruments + DAQ
It is very nice
when you turn on a Test rig to see what the AC power level is
and the DC rails being used are there, with out havingto start
the computer and load software just to get some simple readings
on the state of the rig.
you may have to add a function to the test after it is built
and adding a low cost bench, panel meter or instrument may do
the trick, quickly without the need to program
A good quality
DMM or handheld scope, even sometimes calibrators are very useful
to add into a Test system. It makes for quick verifications and
trouble shooting around the rig when setting up and if there
USB DAQ for Test
In NZ we have
noticed a trend that started back in about 2000, when many of
our customer's Test Sites started migrating from PXI and GPIB
Test Rigs and going to USB DAQ for Functional Test. This trend has accelerated
over the years. It started with the large manufacturing companies
first, as they reduced the cost of test. (Also read the next
section on other ways for lowering test costs).
Recently a very
good article was put up a site in Linkedin. Have a read. it discusses
USB DAQ for Test now and into the future. link
NB. That if you are doing full
spec RF testing especially then PXI or GPIB Test Instruments
There is a growing
group of Test engineers who are building Test systems using embedded
technology, like Rabbit boards with ADC, DAC, DIO, Timers and
Encoder and PWM ability all on one board. These can be Ethenetted,
Wified to a PC for Control, DB and Report work.
The only downside is the software
which is home spun using C usually. However if you are good at
this and make reusable code, over the years it gets easier to
build test rigs at a very low cost.
Opinion: If I was a Manager of
a company's Test systems, I would be concerned to allow this
practice to develop as it is very Test Engineer centric and if
they leave or the team disbands, then the future can be very
costly to recover.
Last points on
If you are including Ethernet,
WiFi, Bluetooth, ZigBee in your devices, it is a very very good
idea to by modules that are certified rather than spin your own
with parts then go to the expense of certification.
MasTec has a broad range of Certified
Wirless modules for embedding. This will solve many present and
Also do have a look at this link
Drop ( have a go )
Here is the link,
it may amaze you.
on Quick Drop