Model 2465
Gas Piston Gauge

Technical DataFeatures• Autofloat controller and manually operated
systems available• Pressure range: -100 kPa to 7 MPa(-14.5 to 1000 psi) gauge, 1.4 kPa to 7 MPa(0.2 to 1000 psi) absolute• Total uncertainty to 0.0010 % (10 ppm)of reading• Precision better than 3 ppm• Stability better than 1.5 ppm over two years• Gauge, absolute, vacuum (negative gauge),
and low pressure modes

The Model 2465 Gas Piston Gauge has a long
history of serving national standards laboratories, commercial industry and governmentorganizations as a primary pressure standard
for over 40 years. Since its original introduction, enhancements have been made to increase
performance and reduce operator workload.
The autofloat controller configuration is a recent
example of Fluke Calibration’s commitment
to provide an easy to use, high performance,primary standard to the pressure calibration andmetrology community. The Model 2465 provides
the capability of generating pressures to withina total expanded uncertainty of 10 parts per
million to 0.7 MPa (100 psi) and 26 parts per
million to 7 MPa (1000 psi).
The Model 2465 is available in a variety ofconfigurations to meet individual requirements.
The three basic components of the Model 2465
are the Instrument Base, one or more Piston/
Cylinder Assemblies, and a single Mass Set. The
Autofloat Controller can be added to minimize
operator workload and skill requirements, or
select the Manual Pressure Control Pack. Last,
decide which accessories and options will berequired.

Instrument base
The instrument base is designed with functionality, economy and space conservation in mind.
All electronic components are housed awayfrom the instrument base to eliminate errors
caused by thermal effects and magnetic fields.
The thermally isolated motor drive is connectedto the cylinder—eliminating pressure fluctuations and maximizing productivity. A durable,
acrylic bell jar is provided to allow absolute andvacuum modes of operation. A KF16 fitting isprovided to simplify installation and allow low
reference pressures.

Piston/cylinder assemblies
Piston and cylinder assemblies are manufactured from proven materials that have evidenced
superior strength, durability, low distortion, lowthermal coefficients and virtually undetectablehysteresis over the last several decades, andhave an unparalleled record of long-term stability. Tungsten carbide is used for all pistons andcylinders, except where the demand for accurate low pressures is met by using high quality
stainless steel (low range piston). The lower
density of steel facilitates generating pressures
down to 1.4 kPa (0.2 psi).

Four piston/cylinder combinations are
now available to generate pressures over thetotal range of the system. The maximum sinkrate for each piston/cylinder is 0.38 centimeters/
minute (0.15 inches/minute). If lower sink rates
are required, please refer to the Model 2468 Gas
Piston Gauge.

The autofloat controller communicatesthrough an RS-232C interface with WinPrompt®
software, a powerful calibration management
tool. The user can set up procedure files consisting of a table of pressures required to calibrate aparticular device. Each time the device requires
calibration, the operator opens the procedure
file, generates each pressure setpoint, enters
Mass set
the reading from the device, and then saves theresults as a calibration file. Calibration reports
Each mass is machined to a nominal value andis made from non-magnetic materials to provide can be printed from WinPrompt.
For customization, WinPrompt supports thelong-term stability and eliminate sensitivity tomagnetic fields. For ease of use, the entire mass Dynamic Data Exchange (DDE) function of
Windows so that all data can be easily transset totals just 6 kilograms, with a maximum
ferred to word processing and spreadsheet
platter mass of 1 kilogram. A laboratory grade
programs for automated report generation andtrim mass set is included to allow any pressure
increment within the range and resolution of the analysis.
For enhanced software capabilities, Fluke
piston/cylinder assembly.
Calibration offers COMPASS for Pressure
Calibration Management Software. COMPASS
Autofloat controller
software can perform all of the same functions
The autofloat controller provides a means ofas WinPrompt and also can communicate
reducing operator workload while achieving the directly to the device under test, eliminating
unparalleled performance provided by the Model potential errors in the calibration.
2465. The operator simply applies the mass load
as instructed by the software, and then selects
Manual pressure control
the autofloat icon on the menu bar. The autofloat
For manual operation, the Model 2465 can becontroller automatically generates the desired
provided with a manually operated Pressurepressure to establish the correct piston float
Control Pack, instead of the autofloat controller,position. A three-color status bar at the bottomof the software screen indicates when the piston for regulating and controlling the system pressure and float position. The optional Model 2456
is floating within acceptable limits and a readPiston Gauge Monitor and WinPrompt software
ing from the device under test can be entered.
Once the pressure is established, the autofloat add further capability to the manual system (seeseparate Model 2456 data sheet for additional
controller monitors the speed of piston rotation
information and specifications).
and automatically engages the Model 2465
motor as required. Since the motor rotates theOperating modes
cylinder, readings can be taken even when theThe Model 2465 is capable of operating inmotor is operating, avoiding time-consuming
gauge, absolute and vacuum mode.
delays.
Gauge mode: pressure is achieved by simply
The autofloat controller also monitors piston
temperature, float position, reference vacuum in loading the appropriate mass load to the top of
the piston.
the bell jar, and sink rate, along with ambient
Absolute mode: A vacuum pump can betemperature, pressure and humidity to deterconnected to the reference pressure port, using
mine air density when used with the optional
standard KF16 vacuum fittings. The appropriate
LEM. This data is transferred to the software
mass load is applied and the bell jar is placed
which applies all environmental corrections
on the instrument base. The vacuum pumpand updates the generated pressure in realevacuates the bell jar and the residual amounttime. The autofloat controller also activates theof pressure is measured either automatically
vacuum pumps if required.
with the autofloat controller, (or with the Model
To provide additional capability, the auto2456 Deadweight Gauge Monitor, in the manual
float controller is provided with a barometricconfiguration).
reference sensor to allow system operation inabsolute, vacuum (negative gauge) and low
pressure mode.

2 Fluke Calibration

Model 2465 Gas Piston Gauge

Vacuum mode: is achieved by generating asubatmospheric pressure with the Model 2465
and autofloat controller utilizing the internal,
high accuracy, barometric reference sensor. The
system subtracts the generated pressure fromthe barometric reference sensor and displays theresult: a vacuum (negative gauge) pressure.
Low pressure mode: allows operation
down to 0 gauge pressure, and is achieved bygenerating an absolute pressure at or above
atmospheric pressure utilizing the barometricreference sensor in the autofloat configuration.

Accessories
Model 2456 Piston Gauge Monitor and
WinPrompt software: For users who do not
require the autofloat capability, but want to
add a level of automation to the Model 2465.
The Model 2456 continuously monitors piston
temperature, float position, and sink rate, andoptionally air density and reference vacuum.
WinPrompt software calculates mass-topressure and pressure-to-mass values, andautomatically reads and displays real-time
piston gauge parameters.

Lines and fittings kits: Lines and fittings
kits are available to ensure that you have all thecomponents needed to install the system andbegin performing calibrations.
Vacuum pumps: For applications whereabsolute or vacuum mode calibrations will beperformed, two vacuum pumps are required.
The autofloat configuration requires each pump
to be equipped with an auto-vent valve so thatthe vacuum line is vented to atmosphere when
the pump is turned off. Fluke Calibration can
provide high quality vacuum pumps that meetthese requirements. Fluke Calibration supplied pumps also include a backstream filter toprevent contamination of the Model 2465 anddevice under test along with a muffler for quiet
operation.

Specifications
PerformanceGeneral
Pressure range

Gauge mode: 1.4 kPa to 7 MPa (0.2 to 1 000 psi)
Absolute mode: 1.4 kPa to 7 MPa (0.2 to 1 000 psi)
Vacuum mode: -100 kPa to 0 kPa (-14.5 to 0 psi)

Temperature

Operating: 15 °C to 29 °C (7 °F to 92 °F)
Storage: -20 °C to 70 °C (-4 °F to 158 °F)

Electrical power

115/230 V ac, 50/60 Hz, 15 W

Humidity

Operating humidity: 20 % to 75 % RH, non-condensing
Storage humidity: 0 % to 90 % RH, non-condensing

Pressure medium

High purity nitrogen or dry, clean air with less than 0.5 ppm hydrocarbon and less than 5 ppm H2O
content, dew point less than or equal to -50 °C (-58 °F), and less than 50 micron particulate size.
Although lower quality gas can be used, the frequency of piston/cylinder cleaning will increase.

Piston/cylinder assemblies
Low range

Nominal area: 3.4 cm2 (0.52 in2)
Pressure range: 1.4 kPa to 172 kPa (0.2 to 25 psi)
Minimum autofloat pressure: 7 kPa (1 psi)
Total uncertainty: 0.001 % RDG or 0.07 Pa (0.00001 psi)
Materials: Piston is 440C stainless steel, cylinder is cemented tungsten carbide
Thermal coefficient: 1.5E-05/°C

Lower mid range

Nominal area: 0.84 cm2 (0.13 in2)
Pressure range: 11.7 kPa to 0.7 MPa (1.7 to 100 psi)
Minimum autofloat pressure: 34.5 kPa (5 psi)
Total uncertainty: 0.001 % RDG or 0.28 Pa (0.00004 psi)
Materials: Piston and cylinder are cemented tungsten carbide
Thermal coefficient: 9.1E-06/°C

Upper mid range

Nominal area: 0.168 cm2 (0.026 in2)
Pressure range: 14 kPa to 3.5 MPa (2 to 500 psi)
Minimum autofloat pressure: 0.14 MPa (20 psi)
Total uncertainty: 0.0026 % RDG or 2.8 Pa (0.0004 psi)
Materials: Piston and cylinder are cemented tungsten carbide
Thermal coefficient: 9.1E-06/°C

High range

Nominal area: 0.084 cm2 (0.013 in2)
Pressure range: 14 kPa to 7 MPa (2 to 1000 psi)
Minimum autofloat pressure: 0.24 MPa (35 psi)
Total uncertainty: 0.0026 % RDG or 2.8 Pa (0.0004 psi)
Materials: Piston and cylinder are cemented tungsten carbide
Thermal coefficient: 9.1E-06/°C

3 Fluke Calibration

Model 2465 Gas Piston GaugePrecision(type A uncertainty)

Better than 3 ppmb

Long-term stability

Better than 1.5 ppm per
two yearsb

Resolutionc

1 ppm or 1 mg

Mass set
Total mass

6 kg (13.2 lb)

Max platter mass

1 kg (2.2 lb)

Includes trim mass set
Computer interface
Requirements

Pentium level processor,
RS-232C interface,monitor, mouse or otherpointing device, keyboard; program requires
2 MB available hard diskspace; Windows 95 orhigher

Specifications cont.
Autofloat system
Autofloatcontroller

Positive shut-off controller automatically generates pressure and maintains piston float position atdesired pressure. Includes WinPrompt software.

Autofloat range

Low range piston/cylinder: 7 kPa to 172 kPa (1 to 25 psi)
Lower mid range piston/cylinder: 34.5 kPa to 0.7 MPa (5 to 100 psi)
Upper mid range piston/cylinder: 0.14 MPa to 3.5 MPa (20 to 500 psi)
High range piston/cylinder: 0.24 MPa to 7 MPa (35 to 1 000 psi)

Float positiond

Inductive sensor
Float position resolution: 0.002 cm (0.001 in)
Sink rate resolution: 0.001 cm/min (0.001 in/min)

Pistontemperatured

4-wire: 100 Ω PRT
Accuracy: ± 0.1 °C (± 0.18 °F)
Resolution: 0.01 °C (0.018 °F)

Laboratory
Environment
Monitor (LEM)dSensor types
Temperature: thin film platinum 1000 Ω RTD
Humidity: capacitive IC humidity sensor
Barometric pressure: piezoresistive, monolithic
silicon pressure transducer

Vacuum moduled

Thermopile sensor
Accuracy: 10% of reading or 10 mTorr
Resolution: 1 mTorr

Barometricreference sensor

Accuracy: Better than ± 0.014 kPa (0.002 psi) per year
Accuracy in low gauge mode: ± 2.8 Pa (0.0004 psi)
Resolution: 1 Pa (0.00015 psi)

Accuracy
Temperature: ± 2 °C (± 32.216 °F)
Humidity: ± 15 %Pressure: ± 5 mmHg

Vacuum pressure achieved depends on local barometric pressure
Values are reported at the 95 % confidence level (2σ)
Whichever is greaterdAlso applies to Model 2465 equipped with Model 2456 Piston Gauge Monitor.
Additional information is provided in Model 2456 and 2456-LEM literatureabcFluke Calibration. Precision, performance, confidence.™

Fluke Calibration
PO Box 9090,Everett, WA 98206 U.S.A.

Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands

For more information call:In the U.S.A. (877) 355-3225 or Fax (425) 446-5116
In Europe/M-East/Africa +31 (0) 40 2675 200 or Fax +31 (0) 40 2675 222
In Canada (800)-36-FLUKE or Fax (905) 890-6866
From other countries +1 (425) 446-5500 or Fax +1 (425) 446-5116
Web access: http://www.flukecal.com©2010-2011 Fluke Calibration. Specifications subject to change without notice.
Printed in U.S.A. 9/2011 3833653B D-EN-N Pub ID: 11740-eng
Modification of this document is not permitted without written permission
from Fluke Calibration.

4 Fluke Calibration

Model 2465 Gas Piston Gauge