Application Note

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Application Note

Event recording (or logging)

with a Fluke 287/289

Digital Multimeter

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

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

Forms

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.

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 log-

ger is to sample the input signal

at a rate sufficient to track activ-

ity 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 wad-

ing 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 tradi-

tional logger is that the DMM,

while sampling internally at a

sub-second rate, records only

significant changes in the read-

ings. This technique, called

event recording, requires far

less memory. Still, it does an

effective job of monitoring and

logging data from an input sig-

nal, 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 TrendCap-

ture mode, immediately after

the recording session is com-

pleted. TrendCapture is a major

enhancement in the 28X family

over the previous logging capa-

bility of the 189, which had to

upload each recording session to

software to graph and view the

results. The Fluke 289 uses sim-

ilar graphing software (optional)

for detailed analysis, but its abil-

ity to graph even rough details

immediately, onscreen, can

be very powerful. In addition,

the 28X can now hold multiple

recording sessions in it’s mem-

ory allowing troubleshooters to

get multiple sets of data, possi-

bly at different locations, without

having to download each ses-

sion 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

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.

Summary of content (7 pages)

PAGE 1
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® Forms PC software to increase the power of the Recording feature.
PAGE 2
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.
PAGE 3
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.
PAGE 4
Use TrendCapture immediately after recording to do a brief inspection of the recorded data for any suspicious events that might suggest further testing. You can also use it later, in conjunction with the Summary screen, to evaluate or identify multiple saved files in the meter if you didn’t note the saved session name at the time of recording. Remember: TrendCapture can only be used to review recorded data—either the session just completed or a saved data file—it cannot graph in real-time.
PAGE 5
Figure 7. near midnight on Thursday morning. First, the running current was near 5 amps, and then the following cycle lasted for much longer than normal. What we have discovered is the occasional defrost cycle that is a feature of this refrigerator. The 5 amp portion is the operation of the defrost heater, and the longer next cycle is an extended compressor run to remove the excess heat. Zoom choices as well as many other options affecting the graph (Figure 7.
PAGE 6
Figure 10. Session names are available in several categories and use self-incrementing numbers for each session in a selected type. The meter can record four session types: Measurement, Min Max, Peak, and Recording. You can store sessions in any one of the Name categories you choose, although it’s generally a good idea to use the Measurement name category for individual measurement saves and the Recording name for long logging sessions, just to keep things organized.
PAGE 7
Firmware updates to Fluke 287/289 Digital Multimeters The internal programs of these meters are stored in flash memory. As a result, Fluke can now offer product updates and improvements from time to time. This sidebar summarizes new additions to the Fluke 289/287 firmware with version 1.1. Where applicable, these feature changes have already been incorporated into the main body of this application note. The updated firmware may be downloaded from the Fluke website at www. fluke.