Today we're gonna look at what a DAQ is and how you can use one to make quick
temperature measurements. Hi I'm Daniel Bogdanoff and today we're going to take
a quick look at how to make temperature measurements with a data acquisition
system also known as a DAQ. A DAQ system is a general measurement system and they
can measure temperature and some electrical parameters like voltage,
current, resistance, capacitance and more. They may or may not have a built in
source and a built-in DMM to make these measurements easier. If a DAQ does have a
source it's generally a low power source for basic measurement requirements. So in
many DAQ setups you'll need to complement the system by including DC
power supplies, arbitrary waveform generators, or RF and microwave signal
generators. These allow you to provide DC biasing or test signals to your device
under test. Today though we're going to keep it simple and use just the DAQ to
measure a few thermistors on my temperature cube and see how the fan
impacts the system temperature. This is a pretty common test that you might have
to run on your devices. We're using a DAQ 970A and a DAQ M901A multiplexer
module. The DAQ is wired to the temperature cube and can measure the
temperature with its built-in thermistor temperature sensors. We're also using a
USB cable to connect the DAQ to my laptop and using the BenchVue DAQ software to
control it. We're just using a basic temperature cube but a setup similar to
this gets used all the time in the wild. This type of setup could be used to
measure more than just temperature, DAQs can measure all kinds of
electrical characteristics and are often used to test things like AC to DC power
converters, battery packs, medical devices and radio communication devices. So there
are three main steps to making a temperature measurement. First we need to
connect and configure our setup. In this case we're going to use the DAC M901A
modules channels 101, 102, and 103 which are wired to the temperature keeps
thermistor is T1, T2, and T3. Then we're going to open up BenchVue and make sure
we're connected and ready to configure our DAQ. With a modern DAQ, you can set
up, collect and analyze data in a single piece of software. Now that it's
connected we'll go to step 2, setting up our test. In BenchVue, I'm going to set up
the temperature channels in an easy spreadsheet format. We're using 10
Kohm thermistors so I'm going to set each channel to the appropriate setting.
Now that we're set u,p we can run it. I'm going to hit start in BenchVue, and I'm
gonna switch over to my graphics setup so I can watch it running . We can hear my
relays clicking and I'm going to turn my system on. We'll be able to see the
temperatures start to rise as my system runs without any fan. We're gonna give it
a second and turn on the fan and see what happens.
Since our graph has gone off screen I'm gonna go ahead and auto scale in BenchVue
and I'm going to turn on my system's fan. We should now see the
temperature start to drop. You can see the fans had a pretty big impact on our
temperature so for today's purposes that is plenty of information for us. Once
we've run our test, we can move to step 3: exporting and analyzing data. I'd like to
get it in an Excel format but you can also see that BenchVue is providing some
basic analysis for me. So I want to do some post process analysis in Excel so
I'm gonna hit export all and you can see it gives me a couple file options. We're
going to choose excel and export here and it's gonna automatically save that to an
excel file and open that up in the Explorer. When I go to open this up, you
can see it has all of my test information here and when I scroll down
I have all of my data. I should point out that DAQs generally have a memory limit
when running tests. This one can store 100k readings into
its internal non-volatile memory meaning you can power cycle it and not lose your
readings but when connected to bench view it can use the PC's memory to store
up to 1 million readings. So those are the three main steps to making
measurements with a DAQ. Connect everything together, set up your test
procedure and analyze your data. In this case we looked at a simple temperature
measurement to see what impact our fan had in our system but like I said DAQs
can measure so much more. They can be used to monitor and optimize battery
consumption, they can be used to monitor power converters, monitor efficiency of
solar power panels and it can even be used to perform fatigue testing and
mechanical components with strain measurement capabilities. And it can
perform over-voltage and overcurrent measurements with built-in alarm
triggers, so you can trigger alerts if something goes wrong.
For more about DAQs check out the free ebook: For Things to Consider When Using
a DAQ as a Data Logger. There's a link for that in the description. How are you
using DAQs in your test setup? Let us know in the comments. Make sure to LIKE and
subscribe and check out the description for more info on the DAQ70S and BenchVue.
I'm Daniel Bogdanoff, thanks for watching and I'll see you next time.