2
Introduction
2.1
General
The Platinum Resistance Thermometers (PRT) model 5623A is designed to be
a secondary standard interpolating instrument converting temperature to resis-
tance. The 5623A assembly design allows for exposure to very cold tempera-
ture (–200°C) and is an ideal reference for verification, monitoring or
calibrating control sensors in located in freezers or incubators. The 5623A may
also be used as a temperature standard for calibration of industrial sensors. The
PRT is used with a readout device to detect temperature changes or actual tem-
perature. The 5623A covers the range from –200°C to 156°C. Standard length
is 6 inches. Custom lengths are available on request.
2.2
Recalibration
The recalibration of the 5623A PRT should be scheduled according to the
user’s company Quality Assurance requirements. Normally, a PRT is
recalibrated annually. Unless the PRT is used only over a limited range, calibra-
tion over the full range of the PRT (–200°C to 156°C) is recommended. For in-
formation on recalibrating your 5623A, contact an Authorized Hart Scientific
Service Center for an RMA number and current pricing (see Section 1.3).
Depending on the user’s Quality Assurance requirements, the PRT drift should
be checked periodically at the Triple Point of Water (TPW). Section 7,Trouble-
shooting, provides information on drift with respect to mechanical shock and
oxidation.
5623A
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2 Introduction
