The measuring junction of both the 5649 and the 5650 is encased in a 0.25-inch (6.35 mm) alumina sheath that can be ordered in lengths of 20 or 25 inches (50.8 or 63.5 cm) to fit the specific requirements of your application. A reference, or “cold," junction may also be ordered. The reference junction uses a stainless steel sheath and is 8.25 inches long (21 cm) by 0.188 inches in diameter (4.8 mm). The thin diameter minimizes the immersion depth needed, but the extra length ensures you can get all the immersion you like.

Special tin-plated, solid-copper connecting wires with ultra-low EMF properties are used to help retain the integrity of your measurement junction where the probe attaches to your micro voltmeter or Hart Black Stack.

Each probe comes from a spool of wire that has been sample tested using fixed-point standards to ensure uncertainties less than 0.5 °C up to 1100 °C. From 1100 °C to 1450 °C, the uncertainty increases linearly to 3.0°C. If you need greater accuracy, order an individual calibration with fixed-point standards to reduce uncertainties to ± 0.15 °C up to 962°C, ± 0.25 °C up to 1100 °C, and increasing linearly to ± 2.0 °C at 1450 °C.

The probe assembly can be easily disassembled for performing your own bare-wire calibrations