5616 Secondary Reference PRT





5616 Secondary Reference PRT

The temperature range of the 5616 covers –200 °C to 420 °C, and its high-purity platinum element and durability make it great for calibrating in the lab or in the field. When choosing a reference with a platinum element, there are two things you want to look at carefully: the short-term repeatability and the long-term drift. When PRTs are thermally cycled over their temperature range as they would be during a calibration, their resistance at the triple point of water can move up and down within an expected range. Fluke Calibration defines this range (called “short-term repeatability) as the repeatability at the triple point of water during three thermal cycles. 5616s are among the best performing in their class with short-term repeatability better than ± 0.010 °C (± 0.004 °C is typical). In addition, the 5616’s drift is ± 0.007 °C at the triple point of water when exposed up to its maximum temperature (420 °C) for 100 hours. These specifications are given at k=2 and therefore include a 95 % confidence level.

The 5616’s sealed ¬INCONEL® 600 sheath is 298 mm (11.75 in) long and 6.35 mm (0.250 in) in diameter. The probe’s PTFE-jacketed cable is made of silver plated copper that ends with four-wire leads, which eliminate the effects of lead-wire resistance on measurements. Use the 5616 with Fluke Calibration’s 1523/1524 Handheld Reference Thermometer, 1560 Black Stack, 1529 Chub-E4, or 1502A Tweener thermometer readouts.

Each sensor comes with a manufacturer’s report of calibration. The report includes the expanded uncertainty (k=2) at seven calibration temperature points, ITS-90 calibration coefficients, and a temperature vs. resistance table presented in 1 °C increments. Compare the 5616 to other Secondary Reference PRTs. You’ll like its price, but you’ll love its performance.


Durable, accurate sensor for use in the factory, field or lab

  • Temperature range: –200 °C to 420 °C
  • Excellent stability: ± 10 mK
  • Calibrated accuracy ± 0.011 °C at 0 °C
  • Reference-grade platinum sensing element
  • NIST-traceable calibration included

You won’t find another NIST-traceable reference temperature sensor that matches the accuracy and temperature range of the 5616 for the same price.

The 5616-12 is a 100-ohm platinum resistance thermometer (PRT) with excellent short-term repeatability and comes with an unaccredited NIST-traceable calibration.



Parameter Value
Temperature range −200 °C to 420 °C
Nominal resistance at 0.01 °C 100 Ω ± 0.5 Ω
Temperature coefficient 0.003925 Ω/Ω/°C nominal
Calibrated Accuracy[1] (k=2)
± 0.012 °C at −200 °C
± 0.011 °C at 0 °C
± 0.028 °C at 420 °C
Short-term repeatability[2] ± 0.007 °C at 0.010 °C
Drift[3] ± 0.007 °C at 0.010 °C
Hysteresis ± 0.010 °C maximum
Sensor length 50.8 mm (2.0 in)
Sensor location
9.5 mm ± 3.2 mm from tip (0.375 in ± 0.125 in)
Sheath diameter tolerance ± 0.08 mm (± 0.003 in)
Sheath material INCONEL® 600
Minimum insulation resistance 500 MΩ at 23 °C
Transition junction temperature range[4] −50 °C to 150 °C (see footnote)
Minimum immersion length[5]
(< 5 mK error)
102 mm (4.0 in)
Maximum immersion length 254 mm (10 in)
Response time[5] 8 seconds typical
Self heating (in 0 °C bath) 60 mΩ/°C
Lead-wire cable type
PTFE-jacketed cable, PTFE insulated conductors, 24 AWG stranded, silver plated copper
Lead-wire length 182.9 cm ± 2.5 cm (72.0 in ± 1.0 in)
Lead-wire temperature range −50 °C to 150 °C
Calibration NIST-traceable calibration

Calibration Uncertainty

 Temperature Expanded
Uncertainty (k=2)
−197 °C 0.012 °C
−80 °C 0.012 °C
−38 °C 0.011 °C
0 °C 0.009 °C
156 °C 0.011 °C
230 °C 0.013 °C
420 °C 0.021 °C
Note  : Laboratories may periodically reevaluate their uncertainties. Calibration uncertainties depend on the calibration process, the standards used, and the instrument performance.

[1]  Includes calibration uncertainty and 100 hr drift.
[2]  Three thermal cycles from min to max temp, includes hysteresis, 95 % confidence (k=2)
[3]  After 100 hrs at max temp, 95 % confidence (k=2)
[4]  Temperatures outside this range will cause irreparable damage. For best performance, transition junction should not be too hot to touch.
[5]  Per ASTM E 644

Models and Accessories

Model Name Description
5616-12-X Secondary Reference PRT, 6.35 mm x 298 mm 0.250 x 11.75 in), –200 °C to 420 °C
(Calibration traceable to NIST standards included. Not RoHS compliant.)
X = termination. Specify “A” (INFO-CON for 914X), “B” (bare wire), “D” (5-pin DIN for Tweener Thermometers), “G” (gold pins), “I” (INFO-CON for 1521 or 1522), “J” (banana plugs), “L” (mini spade lugs), “M” (mini banana plugs), “P” (INFO-CON for 1523 or 1524), or “S” (spade lugs).

Accessories common to all models  :

Accessory Description
2601 Probe Carrying Case, Plastic 

Knowledge and Information

Product Manuals
application/pdf icon 5616 Platinum Resistance Thermometer User’s Guide (English) (113.04 KB)
Application Notes
application/pdf icon Establishment of a Secondary Temperature Calibration Laboratory (3.09 MB)
application/pdf icon How to Calibrate an RTD or Platinum Resistance Thermometer (PRT) (652.16 KB)
application/pdf icon Temperature measurement and calibration: What every instrument technician should know (1.65 MB)
application/pdf icon Why Use a Triple Point of Water? (1.19 MB)
application/pdf icon Does Immersion Depth Really Matter? (745.44 KB)
Papers / Articles
application/pdf icon Fixed Points for Secondary Level and Industrial Calibration (496.68 KB)
application/pdf icon Fixed Points for Secondary Level Calibrations (560.12 KB)
I Just Got My Probe Recalibrated, Now What?
Platinum Resistance Thermometers (PRT)
application/pdf icon Using a Mini Triple Point of Water System to Improve Reliability in a Temperature Calibration Laboratory (177.86 KB)