In ProcessBook Version 3,
there was a new hybrid
introduced -- a hybrid type of Trend called the
XY Plot, and in the XY Plot,
instead of having Time on the Horizontal
Scale, what you have is another
Tag's Value. So, you are not comparing a
Tag's Values over time, you are
comparing a -- one Tag's Values to another Tag's Values,
and hopefully you are comparing them
at reasonably close intervals.
And, we will show you what we mean by that. If you click on
Draw and XY Plot, you will notice
that the cursor changes
to very -- something very similar to the Trend Object.
I will draw on my little square here.
And this looks very much like the Trend
Control, with a few small differences.
First, let's go to the Tag Search, and in this case,
I have two tags on my
system that are Sine Waves.
They are Sinusoid and SinusoidU,
the difference being that SinusoidU is
based on UTC, and Sinusoid
is based on my, my
current location as my offset from UTC.
And, the difference in the tags in Plot Area
is that in the XY Plot there is a radio button
And we have to tell the system
which tag to use for the X Axis. Now, you can
compare it to multiple tags. I could have five
tags listed here. Whichever tag
had the radio button checked would be the one that
is the base for the comparison, or the
X Axis, the tag's that's along the bottom.
And what we need to do is determine the re... data
retrieval methods for each one of these tags. So, for the X,
X Axis Tag on the bottom, we could
either use an interpolated method or use a recorded method.
Interpolated will get Values
over a certain period of time. Let's, let's do
Now minus two hours. And it will get those
Values every ten minutes, and you can put any,
any Value in here you want. If you want a little
greater interval, you can do that. And, for
the additional tags, you will notice when I click on the
tag that's not checked with a radio button,
the data retrieval method switches to the Y Tags, and
these I have many choices. I can either use the same
interpolated or recorded choices, or I
can choose to synchronize or match my data
to the, the other tag's data.
I am going to use Synchronize which will
use the same timestamps that we used
for the original tag.
Again, I am going to use my Now minus two hours, and Now
for my Flat Time Interval of five minutes.
And, over in the Scale, we have the same Options
that we had for the Trend Object.
And, the Plot Title I can call
my
Scatter Plot. That's very often what they are called.
And, when we click OK, we can see
that we get a Trend Object
that, instead of Trending Tags Values
over time, we are Trending Tags
Values against one another. And you can see,
if I mouse over one of the Values, you can
see the, the intersection, the, the Value
of SinusoidU vs the Value of Sinusoid. So,
my Value of SinusoidU is
my Y Axis, and my
Value for Sinusoid, which in this case is 98.542,
is the, is along the
X Axis. And, up at the top,
you can see the coefficient
is Negative
.8789. Closer you are
to One is the, the stronger
correlation. Now, the only differing in the
Display Format and the
Plot Format, really, the, the most important disp... difference
is this last and next to last Marker Color.
If you uncheck Match Trace, you can set
individual colors for the last
color and next-to-last, which kind of makes it interesting
because then you can see
where, which direction things are going. And in this case,
my last Marker Color was bright red and my
next-to-last was a littler darker red. So you can see
that we are moving along this Trend in
a certain progression. And you can sort of see which
end of the Trend or which, which way you are going, so
that's [inaudible] of the XY Plot.