Hi.
I'm Bill Griffith, an Application Engineer with Keysight Technologies.
And today we're going to look at the data logger feature which is built into our IntegraVision
Power Analyzer.
The data logging feature is used to capture all the numerical measurements from the IntegraVision
Power Analyzer and right into a USB stick.
We can set both the interval at which the measurements are written to the USB stick
as well as the duration.
Let's go ahead and take a look at the data logger feature now.
So the first thing you'll notice with our data logger is you can create your own file
name.
You can choose to have that file name incremented or you can turn off the increment feature
which overwrites the existing data logger file.
Next we can go ahead and set both the interval which can be as fast as 50 milliseconds or
we can change that and make it as long as 24 hours.
I'm going to select 200 milliseconds.
By selecting 200 milliseconds or higher, we actually get some additional measurements.
We get the total harmonic distortion measurements as well as efficiency measurement log to our
data file.
Our duration can be as short as one second or as long as 365 days.
I'm going to choose 60 seconds.
Now that we have our data logger set up we'll go ahead and start.
And as you can see it's starting to capture data and we have about 50 seconds remaining
on our data logging.
What we're measuring is we're measuring the dynamic power of an inverter.
So we have 12 volts applied to the input so we'll log both the input voltage as well as
the current and measure its power and we'll also look at the output which is 120 volts
AC.
We'll measure both the voltage and the current of our inverter which is driving a lamp.
Okay, our data logger is complete so we'll go ahead and pull out our USB stick which
has a CSV file on it and we'll take a look at it on the PC.
I've opened our CSV file in Excel so you can look at the file.
The first thing I'm going to do is, I'm going to change the numerical format so it's just
easier for me to read so just using Excel to pick a format instead of the scientific
notation.
So the first thing you'll notice is our data is written as rows for each of our intervals
and each row is time stamped so they are separated by 200 milliseconds so you can see each of
the rows.
Then each column represents a different measurement that is captured.
So as you can see there are quite a few measurements captured for each channel.
I'm going to skip to the end to look at the efficiency measurement
and I'm going to go ahead and select the efficiency measurements for over time and go ahead and
graph those.
So I'm going to go ahead and insert a graph.
And as you can see the efficiency varies and this is about a 10 second duration that the
efficiency varies for.
So it's bouncing between 88.7 and 87.80 so something's going on with our inverter if
the efficiency is changing over time.
So we can look at some further data to see where that's coming from and since efficiency
is our channel two power divided by our channel one power, we can look at that power real
quickly.
There are lots of measurements made for each channel so we'll take our power in watts.
And if we look at this one real quick, plot it, you can see that the power is pretty consistent.
It's just a little noise in there and again we're driving a desk lamp with it so that
makes sense so that the variation in efficiency is really not coming from the output power.
So if we look back further in our data and find our power for channel one, select the
data for our power going into our inverter and plot it, sure enough we see the same look
to the wave form as we saw in our efficiency so clearly something is happening on the input
which is changing the output efficiency.
And if we were to listen to our inverter, we can actually hear a small fan that turns
on every 10 seconds.
And that's what we're seeing is as that fan turns on, it takes more power.
The inverter takes more power and then the fan turns off and then the inverter takes
less power making it more efficient.
So that's really what's causing the difference in efficiency.
So we're able to use our data logging feature to find out how this inverter is changing
over time so it's kind of a neat feature.
So that was a quick look at our data logging feature, a very powerful feature.
All the measurements that were taken are using continuous wave form analysis.
In addition to that, the measurements are gapless between the intervals we had set.
So again, a very powerful feature for measuring data over time.
I hope you appreciate it.
Thanks for watching.