Fluke Calibration 1504-156
Tweener Thermometer Readout for High Accuracy Thermistor Probes

  • Tweener for reading high accuracy thermistor probes
  • Battery packs available
  • Best price/performance package
  • Compatible Probes Sold Separately
Click for larger image of the Fluke Calibration 1504-156 Tweener Thermometer Readout for High Accuracy Thermistor ProbesClick for larger image
Fluke Calibration 1504-156 Shown
Product Information
Datasheet 99 KB PDF
Manual 419 KB PDF
PDF HelpPDF Help

1504 Tweener Thermistor Readout

If you need more accuracy in a limited temperature range, the Model 1504 Tweener gives it to you as a thermistor readout. Thermistors are less fragile than PRTs and less likely to be impacted by mechanical shock. Thermistors are more sensitive to temperature, have faster response times, and come in many shapes for different applications.

Typical accuracy of a 1504 is ±0.002 °C with a resolution of 0.0001 °C.

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 1504 accurately measures the resistance of the probe and then converts the resistance to a temperature value using its built-in algorithms.

For convenience, the 1504 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 1504 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 1504. 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 Fluke Calibration's 9320A Battery Pack. Our 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 1504 
Temperature Range  Any thermistor range
Resistance Range  0 Ω to 1 MΩ, auto-ranging
Probe  Thermistors
Characterizations  Steinhart-Hart thermistor polynomial
Callendar-Van Dusen: R0, a, d, and b
Resistance Accuracy
(ppm of reading) 
0 Ω to 5 KΩ: 0.5 Ω
5 KΩ to 200 KΩ: 100 ppm
200 KΩ to 1 MΩ: 300 ppm
Temperature Accuracy  ±0.002 °C at 0 °C
±0.002 °C at 25 °C
±0.004 °C at 50 °C
±0.010 °C at 75 °C
±0.020 °C at 100 °C
(Using 10 KΩ thermistor sensor, a=0.04. Does not include probe uncertainty or characterization errors.)
Operating Temperature Range  13°C to 33°C 
Resistance Resolution  0 Ω to 10 KΩ: 0.01 Ω
10 KΩ to 100 KΩ: 0.1 Ω
100 KΩ to 1 MΩ: 1 Ω
Temperature Resolution  0.0001°C 
Excitation Current  2 and 10 μA, automatically selected
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
(Sold Separately)
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 Now Price
MFR ID: 1648966
Fluke Calibration 1504-156 Tweener Thermometer Readout for High Accuracy Thermistor Probes Buy Now $2,675.00
Related Products
MFR ID: 1648927
Fluke Calibration 1502A-156 Tweener Thermometer Readout for RTD, PRT, or SPRT Type Probes Buy Now $2,685.00
Included Accessories
  • 1 - User Manual
  • 1 - Power Cord
  • 1 - Probe Connector*
*Optional Probe must be purchased separately
Battery Pack must be purchased separately
Optional Accessories
MFR ID: 1650686
Fluke Calibration 2505 Connector, Spare DIN, 5 pin for 1502-4 Buy Now Sale $90.00
(Reg. $100.00)
9301 Protek 9301 1Ch. Synth. Function/Arbitrary Wave Form Generator Buy Now
MFR ID: 1658732
Fluke Calibration 9934-M LogWare Software, 1-chan, Multi User Buy Now Sale $657.00
(Reg. $730.00)
MFR ID: 1658744
Fluke Calibration 9934-S LogWare Software, 1-chan, Single User Buy Now Sale $346.50
(Reg. $385.00)
MFR ID: 1652473
Fluke Calibration 5610-6-B Probe, Thermistor 1/8 in. x 6 in. SST Buy Now Sale $859.50
(Reg. $955.00)
MFR ID: 1652506
Fluke Calibration 5610-6-G Secondary Reference Thermistor Stainless Steel Probe, 6-inch, Gold Pins Buy Now Sale $859.50
(Reg. $955.00)
MFR ID: 1652550
Fluke Calibration 5610-6-S Secondary Reference Thermistor Stainless Steel Probe, 6-inch, Spade Lugs Buy Now Sale $859.50
(Reg. $955.00)
MFR ID: 1652592
Fluke Calibration 5610-9-G Secondary Reference Thermistor Stainless Steel Probe, 9-inch, Gold Pins Buy Now Sale $859.50
(Reg. $955.00)
MFR ID: 1652646
Fluke Calibration 5610-9-S Secondary Reference Thermistor Stainless Steel Probe, 9-inch, Spade Lugs Buy Now Sale $859.50
(Reg. $955.00)