Fluke Calibration 525B is a versatile temperature and pressure calibrator designed for professional calibration laboratories, instrument workshops and automated calibration systems. It combines high-accuracy temperature simulation and measurement with DC voltage and current sourcing, resistance functions and optional pressure measurement using external Fluke pressure modules.

The 525B is particularly well suited for laboratories with a large temperature calibration workload. It can source and measure a comprehensive range of RTDs and thermocouples and supports direct entry and storage of ITS-90 coefficients for precision platinum resistance thermometers.

For electrical and process instrumentation, the calibrator provides DC voltage output from 0 to 100 V and DC current output from 0 to 100 mA. Resistance can be sourced from 0 to 4,000 Ω.

Pressure measurement capability is added using compatible external Fluke pressure modules. Depending on the selected module, pressure ranges from very low differential pressures to 10,000 psi (69 MPa / approximately 690 bar) can be covered.

Standard RS-232 and IEEE-488 (GPIB) interfaces enable the Fluke Calibration 525B to be integrated into automated calibration systems. The instrument is also compatible with Fluke Calibration MET/CAL software for automated calibration procedures and documentation.

At europascal, we provide professional calibration solutions for temperature, pressure and electrical measurement equipment. We can also support existing Fluke Calibration 525B installations and help identify suitable current solutions for replacement or modernization.

For professional calibration and metrological traceability of process calibrators, temperature measuring equipment and electrical measuring instruments, use the europascal Calibration Service.

Your Benefits at a Glance

• Professional temperature and pressure calibrator

• Thermocouple source and measurement

• RTD source and measurement

• SPRT measurement

• Direct storage of ITS-90 coefficients

• YSI 400 thermistor support

• Ni 120 support

• Cu 10 support

• DC voltage output from 0 to 100 V

• DC current output from 0 to 100 mA

• Resistance source from 0 to 4,000 Ω

• Resistance measurement from 0 to 4,000 Ω

• RTD source uncertainty down to 0.03 °C

• RTD measurement performance down to 0.015 °C for Pt100

• SPRT measurement performance down to 0.02 °C

• Internal and external cold junction compensation

• Optional pressure measurement

• Compatible with Fluke 700 and 750P Series pressure modules

• Pressure measurement up to 10,000 psi with suitable modules

• Eight programmable setpoints

• Programmable dwell times

• RS-232 interface

• IEEE-488 / GPIB interface

• MET/CAL automation support

• Compact benchtop design

• Ideal for calibration laboratories

• Ideal for instrument workshops

Temperature Calibration for Professional Laboratories

The Fluke Calibration 525B was designed with a strong focus on temperature calibration.

It can simulate and measure a broad range of temperature sensors used in laboratories and industrial process instrumentation.

Supported sensor technologies include:

• Thermocouples

• Platinum resistance thermometers

• RTDs

• SPRTs

• Nickel resistance sensors

• Copper resistance sensors

• YSI 400 thermistors

This broad sensor support allows the 525B to replace several individual temperature simulation and measurement devices in a calibration laboratory.

Thermocouple Source and Measurement

The Fluke Calibration 525B supports the following thermocouple types:

• B

• C

• E

• J

• K

• L

• N

• R

• S

• T

• U

The calibrator can both source and measure thermocouple signals.

This enables the calibration of a wide range of thermocouple-based equipment, including:

• Temperature indicators

• Data loggers

• Temperature transmitters

• Process controllers

• Recorders

• Field calibrators

• Temperature measurement systems

Cold Junction Compensation

Accurate thermocouple calibration requires proper consideration of the reference junction temperature.

The 525B provides selectable:

Internal Cold Junction Compensation

and:

External Cold Junction Compensation

External CJC capability is particularly useful when remote reference junctions or specialized thermocouple calibration arrangements are used.

This flexibility enables the calibrator to support both routine and demanding thermocouple calibration procedures.

RTD Source and Measurement

The Fluke Calibration 525B provides extensive support for resistance temperature detectors.

RTD simulation enables temperature indicators and transmitters to be calibrated without generating the corresponding physical temperature.

The calibrator produces the resistance that the selected RTD would have at the required temperature.

Fluke specifies RTD source uncertainties down to:

0.03 °C

depending on sensor type and operating conditions.

This makes the 525B particularly useful for precision temperature instrumentation.

Pt100 Calibration

Pt100 resistance thermometers are among the most common industrial temperature sensors.

The 525B supports several platinum resistance thermometer characteristics, including common industrial Pt100 curves.

For Pt100 measurement, Fluke specifies best one-year performance down to approximately:

0.015 °C

under the applicable conditions.

This allows the 525B to serve as both a simulator and a precision measuring instrument for many RTD calibration applications.

SPRT Measurement

The Fluke Calibration 525B can measure 25.5 Ω Standard Platinum Resistance Thermometers.

The specified SPRT measurement range extends from approximately:

−200 °C to +660 °C

with best one-year measurement performance down to:

0.02 °C

This capability makes the 525B particularly valuable in temperature calibration laboratories using precision platinum resistance thermometers.

ITS-90 Coefficients

One of the important temperature metrology features of the Fluke Calibration 525B is direct support for ITS-90 coefficients.

Individual coefficients for characterized resistance thermometers can be entered and stored directly in the calibrator.

This allows the 525B to calculate temperature according to the characteristics of the individual thermometer rather than relying exclusively on a generic sensor curve.

This is particularly useful when working with calibrated SPRTs and precision PRTs.

Additional Resistance Thermometers

In addition to platinum resistance thermometers, the 525B supports other temperature sensor types.

These include:

Ni 120

with a specified measurement range of approximately:

−80 °C to +100 °C

and:

Cu 10

with a specified range of approximately:

−100 °C to +260 °C

The calibrator also supports:

YSI 400 thermistors

for applications within their applicable temperature range.

Resistance Source up to 4,000 Ω

The Fluke Calibration 525B can source resistance from:

0 to 4,000 Ω

This function is important for temperature simulation but can also be used for calibration of suitable resistance measuring equipment.

Fluke specifies best one-year source performance down to:

0.001 Ω

depending on the selected resistance range and test conditions.

Resistance Measurement

The 525B can also measure resistance up to:

4,000 Ω

This enables direct measurement of RTDs and other resistive devices.

Fluke specifies best one-year resistance measurement performance down to approximately:

0.02 Ω

for the applicable range.

The combination of resistance source and measurement capability significantly increases the versatility of the calibrator.

DC Voltage Output up to 100 V

The Fluke Calibration 525B provides DC voltage output from:

0 to 100 V

with a maximum specified load current of 1 mA.

The best one-year voltage source specification reaches approximately:

25 ppm of setting

for the applicable range.

This voltage capability extends the 525B beyond temperature calibration.

Typical applications include calibration of:

• Data loggers

• Recorders

• Process indicators

• Multimeters

• Industrial measurement systems

• Process calibrators

DC Current Output up to 100 mA

The 525B provides DC current output from:

0 to 100 mA

with a compliance voltage of up to:

10 V

The best one-year current source specification reaches approximately:

100 ppm of setting

for the applicable range.

This current capability enables calibration and testing of many process measurement instruments.

Pressure Measurement with External Modules

Pressure measurement capability can be added to the Fluke Calibration 525B using external pressure modules.

Compatible modules include Fluke pressure module families such as:

• Fluke 700 Series

• Fluke 750P Series

• 525A-P Series

The pressure module connects directly to the dedicated front-panel connector.

The 525B automatically detects the connected module type and range.

This makes it possible to expand a primarily temperature-focused calibrator into a versatile temperature, electrical and pressure calibration workstation.

Pressure Ranges up to 10,000 psi

With a suitable pressure module, the Fluke Calibration 525B can measure pressures covering common ranges from very low differential pressure to approximately:

10,000 psi

or:

69 MPa

which corresponds to approximately:

690 bar

The actual pressure measurement range and accuracy depend on the connected pressure module.

The 525B acts as the display and processing instrument while the external module provides the pressure sensor and associated pressure measurement specification.

Multiple Pressure Units

Pressure values can be displayed in different engineering units.

The desired pressure unit can be selected directly from the front panel or through remote communication.

Available units include common SI and non-SI pressure units such as:

• Pa and multiples

• bar

• mbar

• psi

• inH₂O

• cmH₂O

• mmHg

• inHg

This simplifies calibration when devices under test use different pressure units.

Eight Programmable Setpoints

The Fluke Calibration 525B provides eight user-programmable setpoints.

Frequently used calibration values can therefore be stored and recalled quickly.

This is particularly useful for routine checks such as:

• Zero

• Span

• Linearity

• Intermediate calibration points

Instead of entering the same values repeatedly, the operator can recall predefined calibration points.

Programmable Dwell Times

Programmable dwell times further improve automated calibration workflows.

The 525B can remain at a selected setpoint for a defined period before continuing with the calibration procedure.

This allows the device under test sufficient time to stabilize.

Programmable dwell functionality is useful for both automated calibration and troubleshooting.

Compact Benchtop Instrument

Despite its broad functionality, the Fluke Calibration 525B is designed as a compact benchtop calibrator.

Its dimensions are approximately:

13.1 × 31.3 × 47.3 cm

and its weight is approximately:

4 kg

This makes the calibrator suitable for both permanent laboratory installation and flexible use within an instrument workshop.

An optional rack-mount kit is also available for integration into calibration systems.

Five-Way Binding Posts

The electrical connections use convenient five-way binding posts.

These support several common connection methods, including:

• Banana plugs

• Screw terminals

• Spade lugs

• Wrapped wires

• Wire pass-through connections

This provides flexibility when connecting different types of devices under test.

RS-232 and IEEE-488 Interfaces

The Fluke Calibration 525B provides standard interfaces for automated operation.

These include:

• RS-232

• IEEE-488 / GPIB

The interfaces enable remote control from calibration software or custom automation systems.

Commands can be used to select functions, define output values and execute automated calibration procedures.

MET/CAL Automation

The 525B can be integrated with Fluke Calibration MET/CAL calibration software.

MET/CAL enables automated calibration procedures and supports calibration documentation and reporting.

This is particularly valuable for laboratories that need repeatable calibration procedures and structured measurement documentation.

Automated operation can help reduce:

• Manual data entry

• Operator errors

• Calibration time

• Documentation effort

while improving consistency between calibrations.

Calibration Laboratory Applications

The Fluke Calibration 525B is particularly suitable for calibration laboratories with a large temperature workload.

A single instrument can provide reference signals for many different devices.

Typical laboratory applications include:

• RTD indicator calibration

• Thermocouple indicator calibration

• Temperature transmitter calibration

• Data logger calibration

• Recorder calibration

• Process calibrator calibration

• Pressure indicator calibration with external modules

• DC voltage instrument calibration

• DC current instrument calibration

Instrument Workshop Applications

The 525B is also well suited for industrial instrument workshops.

Maintenance technicians often need to calibrate and troubleshoot a broad range of process instrumentation.

The combination of temperature simulation, electrical sourcing and pressure measurement allows one bench instrument to support many different maintenance tasks.

Typical devices include:

• Process transmitters

• Temperature transmitters

• Field calibrators

• P/I converters

• Data loggers

• Temperature probes

• Industrial indicators

Technical Highlights

The Fluke Calibration 525B combines temperature, electrical and pressure calibration capabilities within a compact benchtop platform:

• Temperature / Pressure Calibrator

• Thermocouple source and measure

• Thermocouple types B, C, E, J, K, L, N, R, S, T and U

• Internal and external cold junction compensation

• RTD source and measure

• SPRT measurement

• ITS-90 coefficient storage

• Pt100 support

• Ni 120 support

• Cu 10 support

• YSI 400 thermistor support

• Resistance source to 4,000 Ω

• Resistance measurement to 4,000 Ω

• DC voltage source to 100 V

• DC current source to 100 mA

• External pressure module support

• Pressure measurement to 10,000 psi with suitable modules

• Eight programmable setpoints

• Programmable dwell times

• RS-232

• IEEE-488 / GPIB

• MET/CAL automation capability

Technical Specifications

Feature	Fluke Calibration 525B
Manufacturer	Fluke Calibration
Model	525B
Device type	Temperature / Pressure Calibrator
DC voltage source	0 to 100 V
Best 1-year voltage specification	25 ppm of setting
DC current source	0 to 100 mA
Current compliance	10 V
Best 1-year current specification	100 ppm of setting
Resistance source	0 to 4,000 Ω
Best resistance source specification	0.001 Ω
Resistance measurement	0 to 4,000 Ω
Best resistance measurement specification	0.02 Ω
Thermocouple types	B, C, E, J, K, L, N, R, S, T, U
Best TC specification	Down to 0.12 °C
Pt100 measurement	−200 °C to +660 °C
Best Pt100 specification	0.015 °C
SPRT 25.5 Ω measurement	−200 °C to +660 °C
Best SPRT specification	0.02 °C
Ni 120	−80 °C to +100 °C
Cu 10	−100 °C to +260 °C
YSI 400	15 °C to 50 °C
Pressure measurement	External pressure modules
Maximum pressure	Up to 10,000 psi / 69 MPa with suitable module
Interfaces	RS-232 and IEEE-488 / GPIB
Typical settling time	Less than 5 seconds
Operating temperature	0 °C to 50 °C
Calibration temperature range	15 °C to 35 °C
Storage temperature	−20 °C to +70 °C
Weight	Approx. 4 kg
Dimensions	Approx. 13.1 × 31.3 × 47.3 cm

Why Choose the Fluke Calibration 525B?

The Fluke Calibration 525B combines a strong temperature calibration capability with useful electrical sourcing and optional pressure measurement.

Its ability to source and measure thermocouples and RTDs makes it particularly attractive for laboratories with a large temperature workload.

Direct support for ITS-90 coefficients further extends the instrument into precision platinum resistance thermometer applications.

DC voltage output up to 100 V and DC current output up to 100 mA allow the same instrument to calibrate a variety of electrical and process measuring devices.

External Fluke pressure modules extend the system into pressure measurement, with suitable modules covering pressures up to 10,000 psi / 69 MPa.

Eight programmable setpoints and programmable dwell times simplify repetitive calibration procedures.

RS-232 and IEEE-488 interfaces allow the calibrator to be integrated into automated laboratory systems, while compatibility with MET/CAL supports automated calibration and documentation.

The Fluke Calibration 525B is discontinued. Fluke currently identifies the 7526A Precision Process Calibrator as the recommended replacement. The 525B nevertheless remains relevant for laboratories that already operate the instrument or require information, service and calibration support for an existing system.

At europascal, we can support existing Fluke Calibration 525B installations and assist with selecting an appropriate current calibration solution when replacement or modernization is required.

For professional calibration and metrological traceability of temperature calibrators, process calibrators and electrical measuring equipment, use the europascal Calibration Service.

Discover more Fluke Calibration products here.

Manufacturer information about the Fluke Calibration 525B is available on the official Fluke Calibration 525B product page.

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