Fluke 287-RMS Service Guide

Event recording (or logging)

with a Fluke 287/289

Digital Multimeter

One of the major features of the Fluke
280 Series digital multimeters (DMM) with
TrendCapture is their ability to record
measurement data or “do logging.” This
application note explains what kind of
logging these meters can perform, how
to use the recording feature, and what
information it can provide. This note also
discusses how to use FlukeView
PC software to increase the power of the
Recording feature.

For the balance of this note, we will
refer to the Fluke 289 DMM, although the
information is equally applicable to the
Fluke 287 DMM.

®

Forms

Application Note

Note: This article references features

included in a firmware upgrade to the 289
DMM released in August, 2008. To obtain
the latest firmware version, visit www.
fluke.com/software-downloads. For
a summary of the changes, reference the
end of this document.

Differences between
the Fluke 289 DMM and
a data logger

The Fluke 289 does not do data
logging in the traditional sense.
Typically, the goal of a data log­ger is to sample the input signal
at a rate sufficient to track activ­ity that you might find in the
signal. This often means that it
is desirable to sample the input
as fast as possible so you don’t
miss anything. The problem
with this approach is you need
a large storage place for the fast
data sampling that is taking
place. You can also end up wad­ing through a lot of redundant
data that is considered “normal”
to find the exceptional data (or
lack thereof).

The difference between the
Fluke 289 DMM and a tradi­tional logger is that the DMM,
while sampling internally at a
sub-second rate, records only
significant changes in the read­ings. This technique, called
event recording, requires far
less memory. Still, it does an
effective job of monitoring and
logging data from an input sig­nal, enabling you to detect if
and when the monitored system
is operating abnormally.

The other difference is that
the Fluke 289 DMM can graph
the data onscreen in TrendCap­ture mode, immediately after
the recording session is com­pleted. TrendCapture is a major
enhancement in the 28X family
over the previous logging capa­bility of the 189, which had to
upload each recording session to
software to graph and view the
results. The Fluke 289 uses sim­ilar graphing software (optional)
for detailed analysis, but its abil­ity to graph even rough details
immediately, onscreen, can
be very powerful. In addition,
the 28X can now hold multiple
recording sessions in it’s mem­ory allowing troubleshooters to
get multiple sets of data, possi­bly at different locations, without
having to download each ses­sion as in the past.

Introduction to event
recording

Event recording can be thought
of as an extension of the “Touch
Hold” feature of the original
Fluke 87 DMM. (Touch Hold is
now called “Auto Hold” on the
287/289.) When the Auto Hold
feature is activated, the meter
waits until a period of stability

From the Fluke Digital Library @ www.fluke.com/library

Figure 1.

has been reached, then it beeps
and freezes (holds) a stable
reading on the display for the
user to see. If the input changes
to the point that it is no longer
stable, then becomes stable
again, the meter will beep a
second time and hold a new
reading on the display.

Event recording uses a similar
scheme. When the Fluke 289 is
recording, it is looking for peri­ods of stability. For each stable
or unstable period the meter
logs a start time, the initial
reading, stop time, the maximum
reading, minimum reading (and
the times of their occurrence)
and average reading during
that period. The event recording
feature is designed to store only
enough information to describe
any changes; i.e., events, to the
input signal.

Event recording data

The Fluke 289 excels at record­ing transition events, but while
it has TrendCapture graphing
capability, it does not have the
kind of large graphical display
resolution needed to analyze all
of the event data. This is where
FlukeView Forms software takes
over, allowing you to view the
recorded data in table or graph
form on a PC. An example is
shown in the figure below.

Looking at this data, you can
see that the recording session
started at 1:54:41 PM and ended
at 2:23:47 PM with an elapsed
time of about 29 minutes. You
can also see that the signal
being measured was stable near
119 V for most of the logging
session.

However, there was one
unstable event detected by
the meter during a 1.6-second
period beginning at 2:18 PM.
The graph clearly shows the
switching event that happened
at that time. What is interest­ing about this example is that
the table of data shows only six
“events” needed to be stored
in the meter memory over the
entire 29 minutes of logging
to capture the essence of what
happened.

What this illustration shows is
that, with event recording, only
a very small amount of memory
is needed to store the informa­tion. To capture the same data
using traditional data logging
would require a one-second
sample rate over the entire 29
minutes which would have
produced 1,740 records of data,
yet that level of detail was not
required to detect the problem.

Recording—by the
numbers

Now that we know how the
Fluke 289 records data, let’s
go through the step-by-step
process for recording a desired
signal over time. In this case,
the test will record the signature
of the current drawn by a large
household refrigerator for more
than one day.

The following steps can be
generalized to any recording
situation.

Step 1

Make sure that the battery
indicator in the upper left hand
corner of the Fluke 289 display
shows at least two of the possi­ble four bars, indicating enough
charge is left for a 24-hour oper­ation. For any longer recording
period, or if in doubt, replace the
batteries with fresh new ones.

Step 2

Connect the meter to the
circuit being measured.

In this example, the ac current
was measured by connecting
a current transformer probe to
the mA jacks of the Fluke 289.
That is because the probe output
is 1 mA/A. We then place the
jaws of the probe around the
circuit conductor in the distri­bution panel that is connected
to the breaker dedicated to the
refrigerator. If the DMM function
switch is in any position except
A/mA or μA, the meter will beep
to indicate that the switch must
be in one of these two posi­tions to proceed, and the display
information screen will show
the details. In this case, we
want the A/mA function. The
meter will sense the presence
of the lead in the mA jack, and
select the proper circuit for the
recording.

Note: Although not required in this
case, if a signal normally varies a full
point, you might want to estimate a
maximum current or voltage that you
expect to encounter, and set manual
ranging to the higher range. This will
prevent recording multiple events due
to auto-ranging.

Step 3

Press the Save (F2) softkey
and highlight the Record option
using the navigation arrows.
Then, press the Record (F1)
softkey below the display.

At this point, the Recording
information screen appears.
Note that the bottom line of this
display indicates the battery
condition. If the battery is par­tially discharged, the Battery:
partly empty advisory appears.
See step 1 above.

2 Fluke Corporation Event recording (or logging) with a Fluke 287/289 Digital Multimeter

16

12

8

4

0

00:0009:30 19:00 28:30 37:33

m
A
A
C

1.830 mA AC 01:57:42pm HH:MM

05/30/08 07:03:09pm

06/01/08

08:35 am

x1

16

12

8

4

0

14:36 16:36 18:36 22:3620:36

m
A
A
C

1.944 mAAC 02:21: 01pm HH:MM

05/30/08 07:03:09pm

06/01/08

08:35 am

x3

Important

These next steps (7 through 9) should be
performed immediately after the test is
ended, or when you return to retrieve you
meter, before you explore the data on screen.
This is to make sure you save the recorded
data in a known and easy to recall location.

3 Fluke Corporation Event recording (or logging) with a Fluke 287/289 Digital Multimeter

Step 4

Using the navigation arrows,
highlight Set Duration and
press Edit ( F1). Edit the duration
setting to 07 Days 00 Hrs 00
Min. (We can always manually
stop the recording procedure
earlier if we like.)

Note: Recording duration and sample
interval times may interact — setting
one variable may adjust the other to
fit the recording session within the
available memory.

Step 5

When Duration and Sample
Interval settings have been
changed to desired values, press

OK ( F1) to accept the changes.

Step 6

Press the Start (F2) softkey to
begin recording. You can now
leave the meter unattended.
The 289 will record the current
(amps) used by the refrigerator.

Note: While recording is active (1) the
power button LED will flash on and
off, (2) five minutes after any button
press, the display will turn off to con­serve battery power. Press any button
to turn the display back on, and (3)
the display will show the start time,
the remaining time and number of
recorded interval samples and events.

Step 7

Recording is stopped in three
ways: (1) Automatically when
the recording duration time
has reached, (2) Automatically
when the battery level becomes
critically low or (3) Manually by
pressing the Stop (F4) softkey.
When recording is stopped,
the power button LED will stop

flashing on and off. Note that
once the recording session has
stopped, you cannot resume that
session.

Note: Returning to Stopped Screen
after meter auto powers off: When

recording ends automatically due to
duration time being reached, the dis­play is turned on (if it had been off)
and the meter will power off accord­ing to the Auto Power Off setting in
Instrument Setup (never or N minutes).
If the recording ends due to the bat­tery becoming critically low, the meter
will immediately power down. Turn
the meter back on. If the battery is
showing empty, turn the meter off and
replace the batteries. Turn the meter
back on. The meter will start showing
the display as if you were at the start

of Step 8.

Step 8

Press Save (F2) to bring up the
Save display.

Step 9

Press the +Name (F1) softkey
to select the recording session
name to be associated with this
saved data. In this case, since it
is a recording, you might choose
to highlight Recording and note
that a boxed number appears.
This number is automatically
incremented each time you do a
save using that save name. Note
this saved name (including its
number) so that you can easily
identify the source of the data
in memory after you upload it to
FlukeView Forms. That’s because
you could easily have ten or
more recordings in memory
before you return to a computer.

Step 10

Now, press Save ( F1) one more
time to complete the storage of
the test data in the DMM mem­ory. The display screen will now
show the Start time, the Dura­tion of the test, and the number
of Interval samples and Events
that were stored.

Congratulations!

You have successfully completed
a recording session and saved
the results in the meter. You can
now turn the meter off, or use
it for other purposes until you
choose to transfer your data to a

computer.

Using TrendCapture

You may now safely press the
Trend (F3) softkey to view
the stored results in graphi­cal format. A vertical cursor
will appear in the center of the
TrendCapture display. Using the
navigation keys, you can move
this cursor over areas of interest
in the graph and the value and
time of recording for that value
will appear.

Figure 2. Single refrigeration cycle.

The first thing to note is that
the graph has been scaled to
20 mA. Here’s what’s happening.
The current level was mostly at
about the 2 mA level when the
compressor was running. The 18
mA “spikes” show the momen­tary motor starting current each
time the compressor ran.

The blank gap near the center
of the screen is interesting, so
now we’ll use the TrendCapture
Zoom feature, using the up­down navigation keys, to look at
the detail.

Figure 3. Single cycle, zoomed.

While in Trend mode, the
F3 menu selection changes to
Summary. Press the softkey to
see the session summary data,
including the Start Time and
Duration of the recording and
the number of Interval Samples
and Events recorded. The main
display shows the last recorded
value in the session.

Note: Time scale for Figure 2 and 3 is
elapsed time.