As of Asset Framework 2016,
we can capture child Event Frames with the analysis service.
Child Event Frames are useful when you need to send
escalating notifications or perform in-depth
analysis for past events. To create the
parent child Event Frame hierarchy, we'll
utilize multiple start triggers and differing severities.
For example,
as a process engineer, I know when my temperature
in my press reaches a threshold I'm in the heating phase. I'd
like to capture every time I'm heating my equipment, so that I can
optimize the process. Additionally,
I know that if my process gets too hot,
something is wrong. I'd like to highlight the times that my asset may be
overheated.
In PI System Explorer, I'm concerned
with my Houston press 5, specifically the internal
temperature. To begin capturing my Event
Frames, I'll go the analysis tab.
I'll create a new
analysis and I can give it a
name.
Next I will select my
analysis type. In this case it will be Event Frame
Generation. After I select
Event Frame Generation, the Event Frame template drop down will
appear. This was created earlier and it
shows the different attributes that I'd like to capture for each
Event Frame created. In my case, I created one called
Process.
Now I'm ready to create my start triggers.
The first start trigger I'll make is when
my process goes into the heating phase. In that case,
it's when the process goes above 36
degrees. Because the value that I care about is an
attribute, I'll enclose it in single
quotes.
This start trigger is almost complete. I will give it a
severity of information because this describes my
heating phase.
To
create my second start trigger, I'll click on the bottom and add a new
start trigger. This start trigger
will show when my asset has entered an over heating phase.
In my case, it's when the internal temperature is over
53 degrees.
For severity here, I will make it
as critical as this will disturb my process
and may ruin the final result.
It is important to note that I don't
need an end trigger in this situation.
Once all of my start triggers are no longer true, which means
that my process goes below 36
degrees, my Event Frame will close. Additionally, it's
worth noting that my start triggers do not need to be
based off of the same variable. I can use
different tags values and different process values in
order to control how my Event Frames and child Event
Frames will ultimately be created. The
last piece is looking at how my Event
Frame is scheduled. I will leave this scheduled as
event triggered. That means anytime
that my internal temperature
updates, I will check to see if I need to enter the Event
Frame. To make this Event Frame active, I'll need to check in my
changes.
Once checked in, I'll
wait to see the green checkmark appear next to my
heating process.
Now that I have the green checkmark, I know
that I'm collecting data and I'll create events if my
process goes above 36 degrees and a critical
event if it goes above
53. Let's see how the events were created as
I take a look at my process. I will begin my
marking the two threshold that create both information and critical
child Event Frames. We can see that once a
process went above 36
degrees, the yellow line, I'm creating an
information child event. Once it crosses the red line,
we can see that I'm creating a critical child Event Frame.
When it drops down below the red line, I'll create
another information child Event Frame. It
goes above the red line to create a critical Event Frame
and it finishes with creating one last information
Event Frame. All of this is contained in the parent Event
Frame. Let's take a look at PI System Explorer
and how we can view our Event Frames. To
view my Event Frames, I will go on the left
to the Event Frames tab.
I can right
click and do a new search.
And I will take a look for the specific
Event Frame that I was showing in my process
before.
I'll select
the Event Frame template
and my element was the Houston
Press 5.
I'll make sure to uncheck
all descendants. All descents will treat child
Event Frames as if they were parents. In this case I only
want to search for the parent Event Frame. At the top
right, I'll hit search.
And let's take a look for our Event
Frame.
As you see here, we started the same that we expected.
We had an information Event
Frame, later a critical Event Frame
followed by information, critical and
lastly information before the processor
returned below 36 degrees and exited the heating phase.
If I take a look at the severity, that matches up
completely. It's important to
note that the severity of the parent
Event Frame will always be the highest severity of any of
its children. Even though we started and ended with information
Event Frames, the severity is marked as critical because we had
at least one instance of a critical
event. Let's take a look at how the effective trigger is
determined to see which child events we will
create. The effective trigger is what will
determine which child event is created. The highest
severity that is true will always be the effective
trigger. If you have the same
severity for multiple start triggers, then the first that
appears in the list that is true at the time will be the
effective trigger. Let's look at a few
scenarios. In the process example that I showed
before, we went from information to critical to begin our
Event Frame. This is the situation
here, however the low severity trigger actually overlaps the high
severity. The parent event includes the total
time that any of the start triggers were
active. The child events that are created
are based off of the highest severity trigger because that becomes the
effective trigger once it is true.
Let's see the example from going from high to
low. Again, the resulting child
events follow the highest severity trigger because
that continues to be our effective trigger.
In the case
that a low severity trigger is in the span of a
high severity trigger, we do not
create the parent child Event Frame hierarchy. This only
creates one Event Frame.
In this last example, we see
when we have this same severity. In this
case, only when the effective trigger changes is
when we create a different child
event.
By using multiple start triggers with differing severities,
we were able to create the parent child Event Frame
hierarchy that we desired to have a better
insight into our process. And now if we ever want to do more
analysis later on, we have the exact
times that are processed deviated or over heated.
We also explored the different behaviors the effective
trigger will take and that determines your child Event Frames.