162CE SPRT Datasheet
Temperature Range –200°C to +661°C
ITS-90 Interpolation Standard
Excellent Stability and Low Self-heating
Rugged, Shatter-proof Metal Sheath
Model 162CE is a long-stem standard platinum resistance
thermometer and satisfies all the requirements as a
defining instrument on the International Temperature
Scale of 1990 (ITS-90). The excellent stability, low selfheating error, and immersion characteristics of this
thermometer meet or exceed the acceptance criteria
required by the most demanding standards laboratories.
The 162CE can be calibrated from the triple point of argon
(–189.3442°C) to the freezing point of aluminum
(660.323°C) with expanded uncertainty (k=2) less than or
equal to 0.001°C, as calibrated by the National Institute of
Standards and Technology (NIST).
The 162CE offers versatility not found with more delicate
glass sheath thermometers. For example; the metal sheath
construction is compatible with all common calibration
media including molten salts. The thermometer is
insensitive to pressure up to 13.8 MPa (2000 psia).
Without risk of breakage, the 162CE can be easily installed
in a rigid calibration fixture having minimal clearance-ideal for dry-well calibrators. With over 35 years of field
experience, the 162CE is built for lasting service.
Model 162CE is suited for calibration over all or part of the
operating temperature range of –200°C to +661°C. We offer
several fixed-point and comparison calibration options
traceable to the NIST. Alternatively, the thermometer may
be submitted directly to the NIST or similar standards
The nominal 25.5 ohm sensing element of the 162CE is
made of annealed platinum wire with purity not less than
99.999%. The wire is formed into a single layer filament
and is supported within a multi-bore ceramic tube and
platinum case (see element illustration on page 2). This
straight wire or "birdcage" configuration ensures strainfree operation, promotes low self-heating, minimizes
inductance, and limits wire displacement caused by
mechanical shock. High purity aluminum oxide is used for
the support tube and insulators, which is not susceptible
to devitrification or dehydration at high temperatures. The
sensing element is hermetically sealed in a Inconel* X-750
sheath containing a dry mixture of helium and oxygen. The
oxygen partial pressure is controlled to optimize
performance over the entire operating range.
The flexible external cable consists of four 20 gage silver
coated copper lead wires, Teflon** insulated, twisted, and
covered with a braided shield and silicone rubber jacket.
Each lead wire is terminated with a gold plated copper
spade lug with a color-coded PVC molded strain relief.
Other lead wire termination options are available to mate
with specific measuring equipment.
Model 162CE is supplied with an attractive storage case
and reusable shipping crate, and should be retained for
possible future transportation.
Platinum Resistance Sensing Element
Electrical Circuit
The thermometer includes four leads so that lead
resistance effectively cancels when used with a four
terminal bridge or meter (see electrical schematic).
Sensitive Portion
The platinum resistor is located within the first 2 inches of
the sheath tip. To minimize conduction error, the standard
should be immersed to an adequate depth. In general, the
depth is dependent upon the temperature and the
medium being measured. Six inches is sufficient in a wellagitated oil or ice bath. The standard is long enough for
accurate measurements in well-designed fixed point cells
or furnaces.
Lead Resistances (4)
Platinum Resistor
Temperature Range
–200°C to +661°C. Head and cable +200°C maximum.
When cycled over the specified temperature range, the
R(0.01°C) shall repeat to within the equivalent of 0.001°C. At
maximum temperature, the R(0.01°C) drift rate shall be less
than 0.002°C per 100 hours. For routine laboratory service,
the stability is typically better than 0.01°C per year.
The temperature rise (self-heating) of the platinum resistor
elements above the temperature of the case is less than 0.5
m°C/mA 2. The nominal value is 0.0003°C with a 1 mA
Insulation Resistance
The insulation resistance from the platinum resistor to the
outside sheath is greater than 1000 megohms at 100 VDC
and room temperature.
Pressure Range
When used in the temperature range, the thermometers
will operate in a 0 to 2000 psia environment.
All dimensions in inches
The response of the resistor is less than 3 seconds when
immersed in 77°C water moving at 3 feet per second from
23°C ambient air. Response is defined as the time required
for the resistor to reach 63.2 percent of a step change in
Resistance-Temperature Relationship
Model 162CE is suitable for interpolating temperatures on
the International Temperature Scale of 1990. The nominal
resistance at 0°C is 25.55 ohms and varies from 4.3 ohms at
–200°C to 86.4 ohms at +661°C. A slope of approximately
0.1 ohms/°C allows for convenient interpolation.
Model 162CE resistance ratio, W, satisfies the requirements
of ITS-90:
W(–38.8344°C) u0.844235
W(29.7646°C) v1.11807
The following information is labeled on the housing:
Rosemount Aerospace Inc.
Standard Platinum Resistance Thermometer
Model 162CE Serial Number ___________
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