Hart Scientific 1502A (1502) Tweener Thermometer
for RTD, PRT, and Thermistor Sensors

One of Hart's best-selling products is the Tweener thermometer, and
there's a reason. No other company, not one, has a thermometer that
comes close to the performance and features of the Tweener for anywhere
near its price.

Model 1502A PRT Readout

The Model 1502A Tweener features accuracy up to +/-0.006°C
(the Model 1504 is even more accurate, up to +/-0.003°C). In addition,
it reads both 100-ohm and 25-ohm probes, has a resolution of 0.001°C
across its entire range and is the smallest unit in the industry. It also has
an optional battery pack for completely portable operation.

Each Tweener is programmable to match any probe's constants for maximum
linearity and accuracy. All probe constants and coefficients are programmed
through simple, front-panel keystrokes. Temperature is displayed in °C, °F, K,
or resistance in ohms.

The 1502A accurately measures the resistance of the probe and then converts
the resistance to a temperature value using its built-in algorithms.

For convenience, the 1502A reads the common industrial grade IEC-751 or “385”
ALPHA RTD without any programming. Enter the actual R0 and ALPHA
of the individual probe for increased accuracy. For maximum accuracy,
use the ITS-90 formulas. The Tweener accepts the subranges 4 and 6
through 11.

ITS-90 formulas reside in its firmware. If your probe has been calibrated for any
of the subranges of the ITS-90, you simply enter the coefficients directly into the
Tweener.

Each thermometer comes complete with an RS-232 interface for automation of
temperature data collection, calibrations, or process control functions.
An IEEE-488 interface is available as an option.

The 1502A is calibrated digitally using the front-panel buttons. You never have
to open the box to calibrate it. This calibration protocol further reduces the cost
of the 1502A. It goes where you go and works the way you want it to.

Want more? There are two more Tweeners for specific applications, including
the Model 1503 High Temperature PRT Readout and the Model
1504 Thermistor Readout.

With our Model 9934 Logware, all three Tweener models may be used for
real-time data acquisition. Collect data and analyze it graphically or statistically.
Additionally, Tweeners may be used as reference thermometers with our
MET/TEMP II software.

If you want freedom from AC power in the field or on the plant floor,
order Model 2502 and we'll install a DC power board in your Tweener.
Then you can connect your own 12-volt DC power or order Hart's 9313
Battery Pack. Our battery gives you three to eight hours between charges.
It includes a charger and a nylon pouch with a belt clip.