Handheld Thermometers
Models 1521 and 1522
Read PRTs/RTDs to ±0.025°C and thermistors to ±0.005°C
Model 1522 stores multiple data sets totaling 10,000 readings
INFO-CON connector allows interchangeable use of calibrated probes
INFO-CON eliminates errors from programming probe data
With the Super-Thermometer, Black
Stack, and Tweener thermometers, Hart
established itself as the clear product
leader for thermometer readouts. Our
pattern of offering more power and more
versatility for less money is indisputable.
Now we underline that fact by introducing the two most powerful handheld thermometers in the world.
The Models 1521 and 1522 are the
first standards thermometers to fit into a
battery-powered handheld package.
They’re as accurate as ±0.005°C! You’ll
only find this level of accuracy in large
desktop units that cost three times more.
It’s no wonder we call the 1521 the Little
Lord Kelvin of thermometry.
Fitting easily into your hand and
weighing only 1 pound (0.4 kg), these
thermometers can go anywhere. And
when they get there, you can have total
confidence in the accuracy of your measurements. The 1522 has the power of a
full data logger, with memory to hold
10,000 readings.
The 1521 and 1522 read both Pt-25
and Pt-100 RTDs as well as thermistors.
PRTs and RTDs, with their wide temperature ranges and stabilities, have long
been favored as temperature standards.
From –200°C to 100°C, the 1521 reads
PRTs accurately to ±0.025°C. Even at
800°C these are high-precision readouts,
accurate to ±0.1°C.
Ultra-stable thermistors offer excellent stability and even greater accuracies
over a more narrow range—typically
from about –10°C to 110°C. At temperatures below 50°C, these Handheld Thermometers read thermistors to ±0.005°C.
Accuracy at 100°C is ±0.02°C.
While a small number of handheld
thermometers on the market offer 0.01°
resolution, they fail to provide the accuracy necessary for the last digit to be
meaningful. Hart’s Handheld Thermometers let you select resolution from 0.1°
to 0.001° and offer the accuracy to support even 0.001° resolution.
Of course, the 1521 and 1522 let you
match the exact resistance versus temperature characteristics of an individually calibrated probe. This is true
standards thermometry. Hart’s Handheld
Thermometers read ITS-90, CallendarVan Dusen, or Steinhart-Hart coefficients for maximum system accuracy.
Models 1521 and 1522
Tells your 1521/1522 whether it’s connected
to an RTD or thermistor. No need to tell your
readout what to do.
Allows you to change probes easily. Simply plug in the new
probe and the 1521 is “married” to it with all the relevant data.
tected interchangeability function and
your thermometer will read only the
probe you specify.
Forget entering calibration constants
yourself, and don’t worry about the mistakes that can so easily occur during that
process. You don’t even need to select
your sensor type. It’s all stored in the
INFO-CON. Simply plug in your probe
Model 1521 and 1522 Handheld Thermometers make excellent reference thermometers for field calibrations.
and you’re ready to take readings. It
doesn’t get any easier.
Information is loaded into the memory of the INFO-CON by Hart when you
purchase a probe or have a probe
recalibrated by Hart. Alternatively, you
may load your own information into an
INFO-CON through the Handheld Thermometer or from the serial port of your
PC with the optional download adapter.
The adapter includes Model 9972 software, which provides an easy-to-use
Windows interface to guide you through
the loading process.
If you’d like to use a Hart Handheld
Thermometer with probes you already
own, no problem! Spare connectors are
available. They connect easily to your
probes, and you can program them
Model 1521 LLK
The 1521 uses a menu system for convenient access to all functions. Calibration and sensor programming functions
are password protected to help prevent
unauthorized access.
“Min” and “Max” functions store the
lowest and highest readings since the last
reset. The “Hold” function freezes and
stores the current reading (up to six may
be stored) for later recall. And the
“Delta” function computes the difference between the current reading and a
Tells your 1521/1522 the serial number and recall
date of the attached probe so you never have to
worry about using a probe that is overdue for
INFO-CON Connectors
Probes attach to the 1521 and 1522
using Hart’s new “INFO-CON” connector. The INFO-CON (partially based on
U.S. Patent 5,857,777) allows you to
change the probes you use without requiring you to reprogram your readout.
A memory chip in the INFO-CON stores
all the critical information about your
probe, including its serial number, recall
date, and calibration constants.
When you connect your probe, the
1521 automatically recognizes whether
you’re using an RTD or thermistor and
downloads the calibration constants and
type of conversion specific to your
probe. It also checks the recall date
stored in the INFO-CON to verify it has
not expired. To dedicate a single probe to
your readout, disable the password-pro-
Stores (in a memory chip) the characterization constants for your RTD or thermistor so there’s no need
to enter them manually or download them from a PC.
These are real algorithms, not approximating conversion methods or electronic
look-up tables. If you want to use common industrial curves, RTDs can be read
using the common DIN 43760 (IEC 751)
curve and thermistors can be read using
the YSI 400 curve.
LogWare software can be used to graphically and statistically analyze data logged to the Model 1522 LLL.
LogWare can also turn either Handheld Thermometer into a real-time datalogger.
reference value, which may be recorded
at any time.
Each thermometer comes complete
with rechargeable nickel-metal-hydride
batteries, an AC adapter/charger, an RS232 cable for connecting to your PC, and
a spare INFO-CON connector. Every
unit also includes a NIST-traceable calibration with actual resistance measurements for your individual meter at 10
points—4 representing typical RTD values and 6 representing typical thermistor
A wide variety of standards-quality
probes are available from Hart in many
different shapes, sizes, and price ranges.
On pages 64 to 75 you’ll find PRTs as accurate as ±0.010°C and thermistors as
accurate as ±0.001°C. The uncertainty of
your probe should be added to the uncertainty of the meter to compute total system uncertainty.
Model 1522 LLL
The Model 1522 has all the power and
great features of the 1521 plus the ability
to log data. Two data acquisition modes
are included.
In “Auto Logging” mode, the 1522
can store up to 10,000 measurements at
user-selected intervals, including the
value, unit of measure, date, and time of
each measurement. If you need more
than one data set, stop recording anytime
and record as many sets as you like up to
a total of 10,000 values. Once the 10,000
value limit is reached, recording stops, so
data is never lost unless you tell the 1522
to clear its log.
The 1522 also holds as many as 25
data labels in its memory so that each set
of data can be uniquely tagged. Simply
select one of the 25 labels you’ve created
before recording data. This label is then
recorded with each measurement.
In “Demand Logging” mode, up to
100 individual measurements can be recorded, each one tagged with one of the
25 data labels. Whether you need a lot of
measurements from one source or single
measurements from many sources, the
1522 is a powerful data recording tool.
With Hart’s Model 9934 LogWare
software (see page 85), data management is easy. Data sets gathered remotely through the 1522 can be easily
downloaded to a PC either as a single file
or as individual files for each data set.
Link the LLL to your PC through a serial
cable or its IrDA port either as ASCII or
binary files. View the data, graph it, or
apply alarms. With LogWare you can record data in real time either from a 1522
or 1521 Thermometer.
One company consistently delivers
powerful metrology products that make
your life easier. Ask other companies
about their handheld thermometers. Ask
them about their thermometers that are
accurate to within a few millikelvin and
that record data at the touch of a button.
Then ask them to give it all to you in one
package. Hart Scientific does—at a
price you’ll love. Call us today and get
the most powerful handheld thermometers in the world.
Technical Tip
Calibrate PRTs over Their Useful Range
Most people use their platinum resistance thermometers over a temperature range that is smaller than the total
operable range published by the
instrument’s manufacturer. When
recalibrating a PRT, select the calibration range based on the intended use
rather than on the manufacturer’s maximum range specifications. This will
save you money because calibrations
over a wider span usually require more
temperature points and therefore cost
more. It will also reduce the wear and
tear on your probe and result in better
measurements since PRTs are generally more stable when used over a narrow range.
Models 1521 and 1522
Handheld Thermometer
Sensor Type
Handheld Logging
Temperature Range
Includes 1522 Thermometer, 9934-S
LogWare, 2374 Dongle
for IR Communication,
and 9318 Case
LogWare, Single Channel, Single User
LogWare, Single Channel, Multi User
Spare RS-232 Cable
Adapter, INFO-CON to
spade lug
Dongle for IR
Mini Thermal Printer, includes power supply,
battery pack, paper,
adapter, cable
Paper, 2375 Printer
Soft Carrying Case,
Hard Carrying Case, fits
1521/1522 and a 12”
Probe Carrying Case
Battery Pack,
0Ω to 500 KΩ
Steinhart-Hart thermistor
polynomial, YSI 400 (2252 ohms)
Temperature Accuracy
(meter only)
–200°C to 100°C: ±0.025°C
100°C to 400°C: ±0.05°C
400°C to 800°C: ±0.1°C
800°C to 962°C: ±0.15°C
0°C to 50°C: ±0.005°C
50°C to 75°C: ±0.01°C
75°C to 100°C: ±0.02°C
0.5 mA
5 µA
Excitation Current
0°C to 40°C
Temperature Resolution
1 second
Measurement Period
1- to 60-second exponential filter
Digital Filter
INFO-CON Connector
RS-232 (Model 1522 also includes infrared interface)
Stores 6 readings in “Hold” mode
Logs 10,000 readings in “Auto
Logging” mode; logs 100 readings
in “Demand Logging” mode.
Memory holds up to 25 data
labels that may be attached to
Demand Log readings or Auto
Log data sets.
6-digit, 7-segment LCD with 16x1 alphanumeric
Rechargeable nickel-metal-hydride batteries (AC adapter included)
7.75" H x 4.2" W x 1.5" D (20 x 11 x 4 cm)
1 lb. (0.4 kg)
Probes from Hart
Contact Hart for a wide variety of precision PRTs and thermistors
10-point, NIST-traceable resistance calibration provided
See our calibration and data acquisition software packages on page 78.
The Model 9318 Hard Carrying Case protects your
Handheld Thermometer, a probe, and all your accessories.
–50°C to 150°C
ITS-90, IEC-751 (DIN “385”),
Callendar-Van Dusen
–200°C to 962°C
0Ω to 400Ω
Probe Connection
Resistance Range
Operating Range
INFO-CON Download
Adapter (with Model
9972 Software)
Pt 25 to Pt 100
Randy still has his first chart
recorder. It’s a wind-up unit
he got for Christmas when he
was five.
Ordering Information