1
Introduction
General
The Platinum Resistance Thermometer (PRT) model 5623B is designed to be a secondary
standard interpolating instrument converting temperature to resistance. The 5623B assembly
design allows for exposure to very cold temperature (–100 °C) and is an ideal reference for
verification, monitoring or calibrating control sensors in located in freezers or incubators. The
5623B 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 temperature. The
5623B covers the range from –100 °C to 156 °C. Standard length is 6 inches. Custom lengths are
available on request.
Recalibration
The recalibration of the 5623B 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, calibration over the full range of the PRT (–100 °C to 156 °C) is
recommended. For information on recalibrating your 5623B, contact Fluke for assistance (see
“How to Contact Fluke”).
Depending on the user’s Quality Assurance requirements, the PRT drift should be checked
periodically at the Triple Point of Water (TPW). For information on drift with respect to
mechanical shock and oxidation, refer to the “Troubleshooting” section of this manual.
Before You Start
Symbols Used
Table 1 lists the International Electrical Symbols. Some or all of these symbols may be used on
the instrument or in this manual.
Table 1. International Electrical Symbols
Symbol
Description
Symbol
Description
X
Electric Shock
O
Off
:
Hot Surface (Burn Hazard)
I
On
W
Read the Users Manual (Important
Information)
I
Fuse
B
AC (Alternating Current)
M
Battery
D
AC-DC
;
C-TICK Australian EMC Mark
F
DC
)
Canadian Standards Association
T
Double Insulated
P
CE Complies with European Union
Directives
.
PE Ground
The European Waste Electrical
and Electronic Equipment (WEEE)
Directive (2002/96/EC) Mark
CAT II
CAT II equipment is designed to protect against transients from energy-consuming
equipment supplied from the fixed installation, such as TVs, PCs, portable tools, and
other household appliances.
