Fluke 725 Multifunction Process Calibrator

The Fluke 725 is a versatile multifunction process calibrator designed for technicians and engineers who need to test a wide range of process instrumentation in the field. Instead of carrying separate instruments for current, voltage, temperature and frequency testing, the 725 combines these functions into one rugged handheld calibrator.

It can measure and source mA, DC voltage, temperature, frequency and resistance, while optional Fluke 750P pressure modules extend its capabilities to pressure measurement.

One Calibrator for Multiple Process Parameters

The Fluke 725 covers many of the signals commonly encountered in industrial process instrumentation:

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  DC current: 0–24 mA
  
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  DC voltage: up to 30 V measurement
  
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  RTDs: multiple Pt and Ni RTD types
  
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  Thermocouples: J, K, T, E, R, S, B, L, N, U and other supported types
  
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  Resistance: up to 3200 Ω
  
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  Frequency: up to 10 kHz depending on function
  
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  Pressure: using compatible Fluke 750P pressure modules
  
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  24 V DC loop power
  
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  mA source and simulate functions
  
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  Auto-step and auto-ramp
  
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  Store and recall frequently used calibration setups
  

This makes the 725 particularly useful when a project involves several different types of process transmitters rather than only 4–20 mA loops.

4–20 mA Loop Calibration

The Fluke 725 provides 0–24 mA measurement, sourcing and simulation, with 0.001 mA resolution and 0.02% + 2 counts accuracy according to the current specification.

Its built-in 24 V loop power supply can power a transmitter while simultaneously measuring the resulting mA signal. This allows technicians to test a transmitter outside the normal control loop and isolate wiring, transmitter or signal problems.

Typical applications include:

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  4–20 mA transmitter calibration
  
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  Process loop troubleshooting
  
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  Analog I/O testing
  
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  PLC signal verification
  
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  Transmitter commissioning
  
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  Control valve signal testing
  

Temperature Transmitter Calibration

The 725 can both measure and source RTD and thermocouple signals, allowing technicians to simulate sensor inputs and verify the output of temperature transmitters.

Supported sensor types include common RTDs such as:

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  Pt100
  
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  Pt200
  
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  Pt500
  
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  Pt1000
  
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  Ni120
  

It also supports a broad selection of thermocouples including J, K, T, E, R, S, B, L, N and U.

This makes the 725 suitable for checking temperature transmitters without requiring a separate temperature calibrator.

Pressure Transmitter and I/P Testing

When used with compatible Fluke 750P pressure modules, the Fluke 725 can measure pressure across differential, gauge, vacuum, absolute, dual and high-pressure applications. Fluke specifies pressure accuracy from 0.025% of range, depending on the pressure module used.

The 725 can also source mA while simultaneously measuring pressure, allowing technicians to perform valve and I/P (current-to-pressure) tests with a single instrument.

This is particularly useful for:

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  Pressure transmitter calibration
  
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  I/P converter testing
  
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  Control valve troubleshooting
  
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  Pressure switch verification
  
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  Valve positioner testing
  

Flowmeter and Frequency Testing

The Fluke 725 includes frequency and CPM (counts per minute) functions for testing pulse-based devices and flowmeters.

It can also perform auto-step and auto-ramp tests, allowing technicians to change the output signal automatically and observe transmitter or control-system response across multiple points.

This is useful for:

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  Flowmeter pulse output testing
  
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  Frequency transmitter testing
  
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  Pulse signal verification
  
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  Linearity checks
  
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  PLC input testing
  

Designed for Field Calibration

The Fluke 725 is built around a straightforward field-service workflow. Its controls are designed without complex menus, while the backlit display improves visibility in low-light conditions.

The compact, rugged design makes it suitable for commissioning, maintenance and troubleshooting in demanding industrial environments.

Key Specifications

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  Current measurement: 0–24 mA
  
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  Current source/simulation: 0–24 mA
  
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  mA accuracy: 0.02% + 2 counts
  
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  mA resolution: 0.001 mA
  
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  Voltage measurement: 0–30 V DC
  
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  Voltage source: up to 10 V / 20 V depending on function
  
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  Resistance: up to 3200 Ω
  
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  Frequency: up to 10 kHz
  
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  RTD and thermocouple: Measure and source
  
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  Loop supply: 24 V DC
  
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  Pressure: Compatible with Fluke 750P pressure modules
  
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  Calibration functions: Auto-step and auto-ramp
  
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  Display: Backlit
  
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  Calibration setup: Store and recall
  
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  Included documentation: NIST-traceable calibration report and data
  

Fluke 725 vs. Fluke 707

The Fluke 707 is primarily a dedicated current loop calibrator for 4–20 mA measurement, sourcing and simulation.

The Fluke 725 is considerably broader. It adds RTD, thermocouple, resistance, frequency and pressure capabilities, making it more suitable when one calibrator needs to cover several process measurement technologies.

In simple terms:

Fluke 707 → specialized mA loop calibration

Fluke 725 → multifunction process calibration

For general process instrumentation maintenance, the 725 offers substantially broader measurement coverage.

Typical Applications

The Fluke 725 can be used for:

Pressure Instrumentation

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  Pressure transmitter calibration
  
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  Pressure switch testing
  
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  I/P converter testing
  
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  Control valve testing
  

Temperature Instrumentation

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  RTD transmitter calibration
  
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  Thermocouple transmitter calibration
  
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  Temperature sensor simulation
  

Flow Instrumentation

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  Flowmeter frequency testing
  
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  Pulse output verification
  
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  4–20 mA flow transmitter testing
  

Process Control

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  PLC analog I/O testing
  
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  Control loop troubleshooting
  
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  Signal simulation
  
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  Transmitter commissioning
  

Maintenance

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  Field calibration
  
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  Linearity testing
  
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  Auto-ramp testing
  
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  Preventive maintenance
  

FAQ

Q: What is the Fluke 725 used for?

A: The Fluke 725 is used for measuring and sourcing multiple process signals, including mA, voltage, RTDs, thermocouples, resistance and frequency, with optional pressure measurement.

Q: Can the Fluke 725 calibrate 4–20 mA transmitters?

A: Yes. It can measure, source and simulate 0–24 mA signals and provides a built-in 24 V loop supply.

Q: Can the Fluke 725 calibrate temperature transmitters?

A: Yes. It can source and measure a wide range of RTD and thermocouple signals for temperature transmitter testing.

Q: Can the Fluke 725 measure pressure?

A: Yes. Pressure measurement is available when the 725 is used with compatible Fluke 750P pressure modules.

Q: Can the Fluke 725 test control valves?

A: Yes. It can source mA while simultaneously measuring pressure, allowing it to be used for valve and I/P testing.

Q: Is the Fluke 725 a HART communicator?

A: No. The 725 is a multifunction process calibrator rather than a dedicated HART communicator. For HART device configuration and communication, the Fluke 154 is the more appropriate instrument.