The Fluke 1502A Tweener (formerly Hart Scientific) 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.
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 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 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.
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.
With our 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 our MET/TEMP II software.
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.
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. (See Calibration Model 1929-X )
Best performance thermometers in their price range
One of Fluke Calibration’s best-selling products is the Tweener thermometer, and there’s a reason. No other company, not one, has a reference thermometer that comes close to the performance and features of the Tweener for anywhere near its price.
|Temperature Range†||−200 °C to 962 °C (−328 °F to 1764 °F)||Any thermistor range|
|Resistance Range||0 Ω to 400 Ω, auto-ranging||0 Ω to 1 MΩ, auto-ranging|
|Probe||Nominal RTPW : 10 Ω to 100 Ω
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
|Steinhart-Hart thermistor polynomial
Callendar-Van Dusen: R0, a, d, and b
(ppm of reading)
|0 Ω to 20 Ω : 0.0005 Ω
20 Ω to 400 Ω : 25 ppm
|0 Ω to 5 KΩ : 0.5 Ω
5 KΩ to 200 KΩ : 100 ppm
200 KΩ to 1 MΩ : 300 ppm
|Temperature Accuracy†||±0.004 °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
|±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||16 °C to 30 °C||13 °C to 33 °C|
|Resistance Resolution||0 Ω to 20 Ω : 0.0001 Ω
20 Ω to 400 Ω : 0.001 Ω
|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||0.001 °C||0.0001 °C|
|Excitation Current||0.5 and 1 mA, user selectable, 2 Hz||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 Fluke Calibration||5615, 5627, 5626, 5628, 5622||5640-44, 5610-65|
|Calibration||ISO 17025-accredited calibration provided|
|†Temperature ranges and accuracy may be limited by the sensor you use.|
|9301||Carrying Case, fits Tweener and 12 in probe|
|2508||Serial Cable Kit|
|1929-2||System Verification, PRT with Readout, Accredited.
Choose two temperature points, extra points at additional cost. Available temperature points are –197 °C, -80 °C , –39 °C, 0.01°C, 30 °C, 157 °C, 232 °C, 300 °C, 420 °C, 500 °C, 660 °C.
|1929-5||System Verification, Thermistor with Readout, Accredited.
Choose two temperature points; extra points at additional cost. Available temperature points are -30 °C, -20 °C, -10 °C, 0 °C, 10 °C, 20 °C, 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C.
|1930||System Calibration, PRT with Readout, Accredited.
Choose PRT temperature range for the calibration. Available temperature ranges are –200 °C to 500 °C, –200 °C to 420 °C, –80 °C to 420 °C, –40 °C to 420 °C, –40 °C to 232 °C, 0 °C to 420 °C.
|1935||System Calibration, Thermistor with Readout, NVLAP-accredited
Choose thermistor temperature range for the calibration. Available temperature ranges are 100 °C span (6 points over span), 60 °C span (7 points over span), 100 °C span (11 points over span).
|Papers / Articles|
|Making the Right Choice for Your Temperature Readout|