Technical data

7250LP Ruska Low Pressure Calibrator

The 7250LP low pressure controller/calibrator, part ofthe versatile Series 7250 family, is specifically designed
to meet the demanding performance requirements ofcalibrating low pressure sensors, transducers, mechanicalgauges, portable calibrators and their plug-in modules.
To accommodate bidirectional devices, the 7250LP can besupplied to operate in both positive and negative gaugemodes.
The 7250LP offers unmatched performance and enhancedcontrol stability. Utilizing multiple ranges in a single
instrument, the 7250LP combines precision, stability,speed and affordability. The 7250LP has a unique quartz
sensor, the most accurate pressure sensing technology
available in a digital pressure calibrator. Each quartz
sensor is manufactured and tested to provide the ultimate
performance required by a Fluke Calibration pressure
calibrator, ensuring that every customer receives thehighest quality, precision and stability in their instrument.

Advanced precision
The 7250LP is available in three different range
configurations:• 2.5/7.5 kPa (10/30 inH2O)• 5/15 kPa (20/60 inH2O)• 10/25 kPa (35/100 inH2O)
Each combination provides a precision to 0.005 % ofreading from 25 to 100 % of the higher range. For pressuresfrom 0 to 25 %, the precision is a fixed error equal to0.005 % of 25 % FS. This unmatched precision is achievedby the unique quartz pressure sensing technology thatputs the pressure in direct contact with the quartz element,eliminating mechanical linkages and metal diaphragms.
Since this is a differential sensor, the reference side of

the 7250LP can be connected to the reference
side (low side) of the device under test. Therefore,
disturbances due to room drafts, HVAC systems
and opening/closing doors, which can have a
detrimental effect on the calibration process, areminimized.
The 7250LP provides both unequalled precision andexcellent long term stability due to the inherent
properties of quartz. For example, the total
uncertainty for a 10/30 inH2O range combination
over a one year calibration interval is 0.009 % ofreading from 7.5 to 30 inH2O. Below 7.5 inH2O,
the uncertainty is the root-sum-square of 0.0075 %Reading and 0.000375 inH2O.

Features• Dual range, select from 2.5/7.5 kPa(10/30 inH2O) or 5/15 kPa (20/60 inH2O)
or 10/25 kPa (35/100 inH2O) rangecombinations• Precision: 0.005 % of reading from 25 %to 100 % Full Scale (FS)• Control stability: 0.004 % of each range• Resolution to 0.01 Pa (0.0001 inH2O)• Time to set point: 30 seconds with noovershoot• Languages: English, French, Chinese,
German, Japanese, Spanish and Italian

High-speed pressure control
The 7250LP will reach the commanded setpointin thirty seconds or less into a 15 cubic inch
volume, with no overshoot. Once at pressure,the proprietary pulse width modulated valves will
maintain the setpoint to within 0.004 %of each range. Therefore, when using the10 inH2O range in active mode, the control
stability is 0.0004 inH2O.

Dual control modes
The 7250LP also provides two user selectablecontrol modes; active and passive. In activemode, the 7250LP is continually maintaining theset point and can compensate for small leaks
and pressure changes due to temperature. Inpassive mode, the user defines a control bandand the 7250LP will turn off the controller once it
achieves the setpoint within the control band.

Automating pressure test andcalibration
The 7250LP is easy to use and can automate yourcalibrations in several ways:

Step up/down
For calibrations where the increments are fixedintervals, enter a user-defined step value. The
7250LP increases or decreases the pressure by
the step amount with the jog dial—no morelengthy keystroke sequences to program.

Sweep test
For simple exercising routines, as withmechanical gauges, enter a start value, a stopvalue, and number of times to repeat the cycle.
The 7250LP will automatically exercise the device
under test prior to the calibration run.

Onboard programs
For frequently used or lengthy calibrations,the 7250LP can store up to 20 user-definedprograms/profiles with up to 1000 steps ininternal memory.

Computer interface

The 7250LP features a unique fused-quartz sensor. This rugged
transducer offers unequalled precision and a stability of0.0075 % of reading per year. The media is in direct contact withthe quartz, eliminating mechanical linkages and diaphragms,
to provide the highest performance available in an automaticcontroller.

The 7250LP is provided with both an RS-232
and IEEE-488 interface, and syntax for all
Series 7250s follows SCPI protocol for easy
programming. COMPASS for Pressure, an offthe-shelf software package, is available. As astandard feature, software written for Ruska’s
previous generation Series 7215, 7010 and 6000
instruments is fully supported by the 7250LP.
The 7250LP can be set to 510 emulation mode touse software originally written for the GE Druck
DPI 510. Firmware updates can be performed
over the RS-232 interface. A LabVIEW driver isavailable.

The 7250LP is specifically designed to calibrate low pressuregauges, transducers and portable calibrators such as the Fluke
750 series, as well as Magnahelics and virtually any low pressure
sensor, gauge or test equipment.
2 Fluke Corporation

7250LP Ruska Low Pressure Calibrator

Versatility to handle any pneumaticpressure calibration

Options and accessories

The 7250LP is versatile enough to handle almost
any type of low pressure calibration.
Dual range: The 7250LP has two ranges in
one instrument and will automatically change
ranges to ensure the highest performance at therequested pressure.
Pressure units/scales: The 7250LP includes morethan 12 standard units of measure, including
inH2O at 4 °C, 20 °C, and 25°C, in Hg at 0 °C and68 °F, kPa, bar, psi, kg/cm2, mm Hg at 0 °C , cmHg at 0 °C, and cm H2O at 4°C, and two userdefined units.
Head pressure: The 7250LP automaticallycorrects for head pressure differences.
Autovent and autozero: With a few keystrokes,
the 7250LP will vent the test port to atmosphereor automatically zero itself.

The 7250LP can be provided for gauge mode
operation, or with:• Vacuum (negative gauge) mode forbidirectional devices• Rack mount kit• COMPASS® for Pressure software
The 7250LP low pressure digital pressure
calibrator can easily automate low pressure test
and calibration workload. The 7250LP is easy
to use, easy to maintain and has the reliability,performance, and features you want.

Calibration
All Ruska 7250LP Low Pressure Controller/
Calibrators come standard with an accredited
calibration report.

Protection of the device under test—The 7250LP
sets upper and lower pressure limits to ensure
protection of the device under test.

Specifications
GeneralFunction

7252
Operating: 18 °C to 36 °C (64 °F to 97 °F)
Storage: -20 °C to 70 °C (-4 °F to 158 °F)

Temperature
Humidity

5 % to 95 % RH, non-condensing

WeightAll models: 7.7 kg (17 lb)

Dimensions (H x W x D)

178 mm x 419 mm x 483 mm (7 in x 16.5 in x 19 in)

Pressure medium

Nitrogen or clean dry air

Display

TFT, VGA, active matrix, 162.5 mm (6.4 in) 640 x 480 resolution, 65,000 colors

Test port and supply connection

1/4 in NPT female

Warm up time

24 hours; may be left on indefinitelyPrecision is defined as the combined effects of linearity, repeatability and hysteresis throughout the operating temperature range.
Expression of accuracy (uncertainty) conforms with the recommendations of the ISO guide to the expression of uncertainty inmeasurement.

Standard pressure ranges
7250LP

Select from three range combinations: 10 inH2O and 30 inH2O or
20 inH2O and 60 inH2O or 35 inH2O and 100 inH2O

Optional mode

Vacuum (negative gauge)

Other Series 7250 digital pressure controllers are available in a variety of ranges from 5 psig to 3000 psig (350 mbar to 207 bar).

3 Fluke Corporation

7250LP Ruska Low Pressure Calibrator

Performance
Precision

0.005 % of reading from 25 % FS to 100 % FS.
Fixed error of 0.005 % of 25 % FS from 0 % to 25 % FS

Stability

0.0075 % of reading per year

Display resolution

User selectable to 1:1,000,000

Control stability

Active mode: 0.004 % of each range
Passive mode: no additional uncertainty

Control response

Optimized for 5 in3 load volume (included with 7250LP).
Maximum 30 in3 load volume

Negative gauge
precision (optional)

Equal to the precision at the corresponding positive pressure.

Total uncertainty
The maximum deviation from the value of pressure including precision, stability, temperature effects and the calibration standardis:
10 inH2O range/30 inH2O range: 0.009 % of reading or 0.00038 inH2O or root-sum-square of 0.0075 % reading and 0.000375 inH2O
20 inH2O range/60 inH2O range: 0.009 % of reading or 0.00075 inH2O or root-sum-square of 0.0075 % reading and 0.00075 inH2O
35 inH2O range/100 inH2O range: 0.009 % of reading or 0.00125 inH2O or root-sum-square of 0.0075 % reading and 0.00125 inH2O

Languages
The Series 7250LP is capable of displaying menus and functions in: English, French, Chinese, German, Japanese, Spanish and Italian

Fluke Calibration. Precision, performance, confidence.™
ElectricalRFTemperature

Fluke Calibration
PO Box 9090, Everett, WA 98206
U.S.A.
Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands
Web access: http://www.flukecal.eu

Modification of this document is not
permitted without written permission
from Fluke Calibration.

Humidity

PressureFlow

Software

For more information callIn the U.S.A. (877) 355-3225 orFax (425) 446-5716
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) 446-6110 or
Fax +1 (425) 446-5716
Web access: http://www.flukecal.com©2010, 2021 Fluke Calibration.
Specifications subject to change without notice.
Printed in U.S.A. 10/2021 211047-en