Fluke Calibration 1502A
Thermometer Readouts for RTD, PRT, & Thermistor Sensors

  • Two Tweeners to choose from-reading PRTs or thermistors
  • Battery packs available
  • Best price/performance package

One of Hart's best-selling products is the Tweener thermometer, and there's a reason. No other company has a thermometer that comes close to the performance and features of the Tweener for anywhere near its price.

1502A Tweener PRT Readout

The 1502A Tweener features accuracy up to ±0.006°C (the 1504 is even more accurate, up to ±0.002°C). In addition, it reads 100-ohm, 25-ohm, and 10-ohm probes, has a resolution of 0.001°C across its entire range, and is the smallest unit in its class. It also has an optional battery pack for completely portable operation.

    Fluke Calibration 1502A Thermometer Readouts for RTD, PRT, & Thermistor SensorsClick for larger image
1502A Shown
Product Information
Datasheet 99 KB
Ordering Info Jump to Product Models, Prices, Accessories, and Ordering Information
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Each Tweener is programmable to match a 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 1502-A-156 accurately measures the resistance of the probe and then converts the resistance to a temperature value using its built-in algorithms.

For convenience, the 1502A156 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 the Tweener's firmware. If your probe has been calibrated for any of the above subranges of the ITS-90, you simply enter the coefficients directly into your 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.


With 9934 LogWare, both 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 MET/TEMP II software.

Battery pack

Want to take your Tweener on the road? Order Hart's 9320A Battery Pack. The battery gives you 36 hours between charges, allowing you to take your work wherever you need.

Calibration choices

Each Tweener and its accompanying probe (sold separately) have their own individual calibration reports. Overall system error can be calculated from the individual errors, rendering the added cost of system data unnecessary. However, for those requiring it, system data is available at two or more temperatures of your choice.

Specifications 1502A 
Temperature Range  -200°C to 962°C
(-328°F to 1764°F) 
Resistance Range  0W to 400W, auto-ranging 
Probe  Nominal RTPW: 10W to 100W RTD, PRT, or SPRT 
Characterizations  ITS-90 subranges
4, 6, 7, 8, 9, 10, and 11
IPTS-68: R0, a, d, a4,
and c4
Callendar-Van Dusen: R0, a, d, and b 
Resistance Accuracy
(ppm of reading) 
0W to 20W: 0.0005W
20W to 400W: 25 ppm 
Temperature Accuracy  ±0.004°C at -100°C
±0.006°C at 0°C
±0.009°C at 100°C
±0.012°C at 200°C
±0.018°C at 400°C
±0.024°C at 600°C
Operating Temperature Range  16°C to 30°C 
Resistance Resolution  0W to 20W: 0.0001W
20W to 400W: 0.001W 
Temperature Resolution  0.001°C 
Excitation Current  0.5 and 1 mA, user selectable, 2 Hz 
Measurement Period  1 second 
Digital Filter  Exponential, 0 to 60 seconds time constant (user selectable) 
Probe Connection  4-wire with shield, 5-pin DIN connector 
Communications  RS-232 serial standard
IEEE-488 (GPIB) optional 
Display  8-digit, 7-segment, yellow-green LED; 0.5-inch-high characters 
Power  115 VAC (±10 %), 50/60 Hz, 1 A, nominal
230 VAC (±10 %), 50/60 Hz, 1 A, nominal, specify 
Size (HxWxD)  61 x 143 x 181mm (2.4 x 5.6 x 7.1 in) 
Weight  1.0 kg (2.2 lb.) 
Probes from Hart 5615, 5627, 5626, 5628, 5622
Calibration  Accredited NIST-traceable calibration provided 
†Temperature ranges and accuracy may be limited by the sensor you use. 
Ordering Information
Model Description Buy Online Price
MFR ID: 1648927
Fluke Calibration 1502A-156 Tweener Thermometer Buy Now $2,605.00
Optional Accessories
MFR ID: 1650686
Fluke Calibration 2505 Connector, Spare DIN, 5 pin for 1502-4 Buy Now $95.00
9301 Fluke Calibration 9301 Case, Rugged Carrying Buy Now Sale $310.50
(Reg. $345.00)
MFR ID: 1658732
Fluke Calibration 9934-M LogWare Software, 1-chan, Multi User Buy Now Sale $643.50
(Reg. $715.00)
MFR ID: 1658744
Fluke Calibration 9934-S LogWare Software, 1-chan, Single User Buy Now Sale $337.50
(Reg. $375.00)