Fluke 1551A, 1552 Specifications

1551A Ex/1552A Ex

Intrinsically Safe

“Stik” Thermometer

The new “gold standard”

of industrial temperature

calibration

Designed

to go where

you work

Finally, a digital substitute

for your mercury-in-glass

thermometers! Accurate

and repeatable to ± 0.05 °C

over its full range, the

1551A/1552A “Stik”

Thermometer is the new

“gold standard” of industrial

temperature calibration.

Whether working outdoors

in environments where

potentially explosive gases

may be present or on the

floor of a processing plant,

the intrinsically-safe, battery-

operated, portable reference

thermometer is designed to

go where you work.

Features at a glance

Accuracy of ± 0.05 °C (± 0.09 °F)

•

over full range

Intrinsically safe (ATEX and

•

IECEx compliant)

Two models to choose from

•

(-50 °C to 160 °C or -80 °C to 300 °C)

User-configurable temperature

•

trend/stability indicator

2 2

Display temperature in °C or °F

•

Optional data logging to internal memory

•

300-hour battery life

•

Percent battery-life and low-battery indicator

•

NVLAP-accredited, NIST-traceable calibration

•

included

Thermometer probe and digital
readout combined into one unit

The stainless steel probe and digital readout are
fixed together and calibrated as a system. The
accuracy specification is easy to understand since
it includes all uncertainty components, including
drift, for up to one year
display rotates 90° making it easy to read from
any angle. A user-configurable stability/trend
indicator lets you know when your temperature is
stable enough to record an accurate measurement.
A user-settable auto-off function extends typical
battery life to three hundred hours. A low-battery
indicator and stop-measure function prevent
erroneous measurements from being made due to
low battery life. A simple three-point calibration
function allows you to easily and accurately
calibrate the “Stik” Thermometer. Data logging to
internal memory of up to 10,000 time-stamped
measurements is optionally available.

1

. The large backlit LCD

Why calibrate process
temperature sensors?

Because temperature greatly effects the
accuracy of a volumetric measurement, process
manufacturers of chemical, pharmaceutical, food or
petroleum products require accurate temperature
measurements—especially for processes where
quality or custody transfer are regulated by
government agencies. Since all temperature
sensors are subject to drift with time, regular
calibration or verification against a reliable
reference thermometer is required. Finding a
reference thermometer that is accurate, repeatable
and robust, however, can be challenging.

What’s wrong with my
reference thermometer?

Industrial reference thermometers available
on the market today, such as mercury-in-glass
thermometers (or “ASTM thermometers”) and
portable electronic thermometers are useful, but
both come with inherent problems. Although
accurate and repeatable, mercury thermometers are
fragile. The risk of a mercury spill poses potential
hazards to the environment and to the health of
personnel. Many of the United States and European
Union countries have already banned their use in
industrial applications. Some organizations have
replaced their mercury thermometers with more
durable portable electronic thermometers, only to
discover that the RTD probes lack the repeatability
and dependability required of a legitimate
reference thermometer.

The best alternative to
mercury thermometers

The Fluke “Stik” Thermometer is accurate, stable
and durable, making it the best alternative to
mercury thermometers and existing electronic
thermometers. The thin-film RTD sensor
incorporates the same characteristics of other
premium reference thermometers designed by
Hart Scientific, but it is more robust and less
susceptible to drift. Accuracy and repeatability,
however, are not sacrificed for improved durability.
Using a glass-stem mercury- or spirit-filled
thermometer at different immersion depths, or
at significantly different ambient temperatures
from which it was calibrated, may require the
application of emergent-stem corrections that can
be tedious but necessary to calculate an accurate
measurement. This isn’t required with the “Stik”
Thermometer. The sensor of the 1551A Ex
requires a minimum immersion depth of only
7 cm (2.8 in), with no appreciable effect on the
measured temperature due to heat loss through
stem conduction.
Some digital thermometers can become less
accurate when used outside a narrow range of
ambient temperatures. This isn’t the case for
the “Stik” Thermometer. Your measurement
remains accurate in ambient temperatures
from -10 °C to 50 °C (14 °F to 122 °F).
With a superior probe design combined
with electronic functions that assist
accurate measurement, the “Stik”
Thermometer surpasses the
capabilities of other digital
thermometers and is
the perfect substitute
for your mercury
thermometers.

1

In order to minimize sensor
drift, the probe should
always be protected
from mechanical shock.

3