Application Note

Application Note
Everyday troubleshooting
with the Fluke 116 DMM
Johns doesn’t always have
access to the specs (or models
numbers) of the equipment he
works on in advance of arriv-
ing at the job site, so he can’t
always check what the voltages
should be. The meter’s ability to
auto-range saves him the time
and hassles of trying different
settings.
When set to Min/Max, the
Fluke 116 can lock in on the
numbers as they change faster
than the naked eye. This allows
him to focus on making a safe
measurement, instead of direct-
ing all of his attention to the
readout.
Johns also uses the tempera-
ture function of the 116. The
temperature probe allows Johns
to diagnose thermal issues in
running PCs. He reads the CPU
and RAM surface temperatures
while the PC is running appli-
cations (normally this is done
in the system’s BIOS, which can
only be accessed before the PC
boots up).
Success stories
Timeplex rack
This Timeplex Data/Voice
Network Exchange Unit was
located in a telcom switch-
ing office in Huntington Beach,
CA. The rack had two banks
of Pioneer Magnetics power
supplies, with two power
supplies in each bank. I had
to replace one in each bank.
Robert I. Johns is the sole
proprietor of ONSITE PC Assis-
tance. A network administra-
tor, Johns works on mostly low
voltage equipment for home
offices and small-to-medium
sized businesses and subcon-
tracts on a variety of larger jobs.
In 2006, Johns started
researching new multime-
ters. Price and reliability were
important to him, but so were
size, resolution, battery life,
Min/Max, auto-ranging, and
temperature. He chose the Fluke
116 DMM (see specifications on
page 3).
As an independent contrac-
tor, Johns negotiates hourly
rates and minimum charges for
service calls. Since his ability to
resolve issues quickly increases
his average hourly rate, it’s
important to save as much time
as possible at every stop. Using
the Fluke 116 has helped him
identify root causes, and in
most cases, it prevents him from
having to take things apart.
Feature background
“Most of the readings I take are
in the lower voltage ranges,
so I needed a high resolution
meter,” says Johns. However:
“The digital readout on the first
meter I bought was limited to
only hundreths. I wasted a lot
of time by doing that.”
Now, he says, “The features
of the 116 that I really love are
the automatic ranging, the abil-
ity to record minimum, and the
positive/secure connection of
the probes to the unit.”
Testing
Functions
Case
Study
Profile: Robert I. Johns, ONSITE PC
Assistance
Tool: Fluke 116 HVAC Multimeter with
temperature and microamps
Measurements: Low voltage,
auto-ranging, min/max, temperature
F r o m t h e F l u k e D i g i t a l L i b r a r y @ w w w . f l u k e . c o m / l i b r a r y