Calibration resources

Calibrating at the bench with a deadweight tester

A deadweight tester is a proven method of pressure calibration that is usually chosen for bench applications when accuracy and reliability are the top requirements. Calibrations are performed at the bench for convenience and to maintain reference conditions.

Hand pumps and pressure test gauges for field pressure testing

It's important to select the proper pump and gauge to match the testing application at hand—a good guideline is the testing device should be 4-10 times more accurate than the device being tested.

Manual approach to pressure switch testing

Calibrating a HART Smart Pressure Transmitter

Verifying and documenting the performance and adjusting a HART smart pressure transmitter can require a bucket full of tools. Performing this task with a HART enabled calibrator like the Fluke 754 simplifies the task and reduces what you need to carry.

Automating Temperature Calibration at the Bench

See the advantages of automating temperature calibration, different ways to achieve automation, and the general steps required. Plus, see related resources.

Simulating thermocouples and RTDs for calibration and testing

Verifying portable thermometers

On-the-spot temperature checks using portable thermometers are frequently performed in the field by technicians in order to ensure product quality.

Temperature transmitter calibration

A new control valve testing process

Proportional smart control valves play critical roles in process industries. Accurately assessing valve performance, however, can be a cumbersome routine.

Breaking new ground without breaking the loop

Early reports from the field suggest that the new Fluke 772 and 773 Milliamp Process Clamp Meters may be game changers, breaking new ground for technicians in the HVAC controls industry. With the feature sets these meters offer, troubleshooting of the most common problems in modern control systems becomes a snap.

How calibration improves optimization

Learn which calibration tools are best for improving optimization and quality in process manufacturing plants including chemical processing, nuclear power, pharmaceutical, pulp and paper.

Troubleshooting 4 to 20 mA Process Control Systems without Breaking the Loop

Troubleshooting 4 to 20 mA (milliamp) process control systems without breaking the loop using Fluke 773 Milliamp Process Clamp Meter

What are customer saying about the Fluke Calibration 5500A Series Multi-Product Calibrator: A Game-Changing Calibration Tool

The Fluke Calibration 5500A Series Multi-Product Calibrator tool streamlines calibration making it the best choice for precision calibration needs.

Selecting a dry-block calibrator

If you are considering a purchase of a dry block, you need to answer 3 questions. See the questions and answers here at this Fluke Calibration blog post.

How to Calibrate a Hygrometer

To prevent these problems, industries with products at risk of spoilage install instruments to measure humidity and temperature continuously through the manufacturing process and also while products are stored.

Pharmaceutical Industry Resource Center

Calibrating a Heat Source using MET/TEMP II

Fluke Calibration provides solutions to all FAQs related to calibrating a heat source using MET/TEMP II.

Calibration Standards

Calibration standards are devices that are compared against less accurate devices to verify the performance of the less accurate devices.

Calibration: Philosophy in Practice, Second Edition

Dry-Block Calibrators vs. Temperature Baths: Choosing the Right One for You

This dry block calibrator vs temperature bath analysis helps you pick the option best for your application. See the comparison in 5 areas of consideration.

Fluke 27GHz RF Calibrator – Concept Test

Mars Science Laboratory

You can bet there is a lot of test and measurement equipment onboard Curiosity. As a test and measurement professional, I’d like to tell you about some of the things I find especially interesting.

Measurement Uncertainty Training Materials

Get 7 free measurement uncertainty training materials including videos, webinars, & articles. Fluke also offers a paid, online course for deeper knowledge.

Non-linear curve fitting using GNU plot

In metrology, what do you do when your curve-fitting software program doesn’t work because you’re dealing with a non-linear equation? Learn here.

Notes from the Tech Support Desk

Read this short blog post to learn how Fluke Calibration technical support works and get some tips on how to prepare for your tech support call.

Operating System Compatibility Chart for Pressure and Flow Calibration Software

Pharmaceutical Industry Resource Center - Field Calibration

Pharmaceutical Industry Resource Center - Laboratory Maintenance

Pharmaceutical Industry Resource Center - Process Automation

Rotameter Calibration

Fluke experts show you how to calibrate a pressure rotameter including a step-by-step rotameter calibration procedure, calibration curve, and tips.

The Case to Revise ISO 17025 - Part 1

It is becoming my opinion that ISO 17025 needs to be revised. This is the first of a series of blog posts that I will be making to demonstrate why the revision needs to be made.

The importance of good insulation resistance in metal platinum resistance thermometers

Understanding the Thermocouple Connector on the 55X0A Multi-Product Calibrators

Learn how to perform accurate temperature calibration using the thermocouple connector on the 55X0A Multi-Product Calibrator.

What is calibration software

When Cal Lab and Service Managers Work Remotely

Fluke Calibration recently hosted a webinar (now available in its entirety as free and on-demand) in which a panel of Fluke associates talked about lessons learned and best practices for working, when some employees can work remotely and others must go to the calibration laboratory

1523/1524 accuracy with selected probes

9 Reasons to Purchase a Fluke 5790B AC Measurement Standard

In this article, electrical calibration expert Marty Kidd explains why someone needs this type of product. He also explains why owners of an old Fluke 5790A should consider moving up to a new 5790B.

A new look at a triumph of engineering and ingenuity from 1968

Lunar reconnaissance is not possible without the precise testing and measurement activity that calibration professionals know so well. Read more here.

Another NCSLI conference is in the books

Another NCSLI conference is in the books. This year, the metrology faithful (and budget funded!) once again gathered to gain knowledge through tutorials and technical presentations, contribute to the industry through attendance of committee meetings, talk to vendors at the exhibition, network with some of the world’s experts in metrology and spend time with old friends. There were so many great things happening that I didn’t even have time to compose a single tweet!

Best practices for your mobile calibration services

This article provides essential tips and best practices for running successful mobile calibration services. Whether you're a mobile calibration technician or looking to add mobile calibration services to your business, this guide will help you stay organized and prepared for any situation.

CalNet Possibilities Fluke

Data Acquisition System Selection Guide

The Fluke Calibration 1586A and Fluke 2638A are two new data acquisition systems that offer great value and performance. This selection guide will help you understand the differences between the two, the strengths of each, and which one will best meet your current and future needs.

Eliminating sensor errors in temperature control loop calibrations

Follow the steps as we demonstrate how to link a documenting process calibrator to a drywell to calibrate a 4-20 mA transmitter and probe in a system.

Flowmeter Calibration: Top 5 Best Practices You Should Know

Fluke 6130B vs 6003A - 5 reasons why the 6130B Electrical Power Quality Calibrator offers better value

Fluke Calibration ceased production and sale of the 6003A Three Phase Electrical Power Calibrator and its specific accessories and options. Fluke introduced this model in 2014 as a competitive power calibrator capable of supplying accurate 3 phases of current and voltage.

High-frequency error sources in oscilloscope calibration

Explore analysis of high-frequency error sources in oscilloscope calibration. Gather insights into the causes, impacts, and methods to mitigate these errors to enhance your accuracy.

How to automate calibration of analog output pressure transmitters

See an example using the Fluke 2271A Industrial Pressure Calibrator to automate testing & calibration of pressure transmitters from 10 in of water to 3000 psi.

How to avoid contamination in pressure calibration

Discover Fluke resources on how & why to prevent contamination in pressure calibration including videos, webinars, and blog posts. Learn more here.

How to remove additional errors when calibrating resistance

Learn the four different connection methods and the tool settings to measure and test resistance on a digital handheld multimeter, a bench multimeter, and a systems multimeter

In a Standards Laboratory, Every Detail Counts

What happens when an electrical standards laboratory’s environmental control system gets old, cranky and hard to maintain? When the lab in question is the Fluke Everett Primary Electrical Laboratory (EPEL), the answer was to replace the air conditioning system, as part of a bigger endeavor to renovate the lab.

Is it Time to Set Up Your Own In-House, Humidity Calibration and Measuring Lab?

Should you bring humidity measurement and calibration in house? Learn to answer this question from the perspective of ROI, requirements, and workload.

Manually calibrating a Digital Multimeter using MET/CAL procedures

Fluke MET/CAL procedures to calibrate a digital multimeter. Watch the video to see how the MET/CAL software walks you through the process.

Measuring the way to a safer global food system

Every year on May 20, World Metrology Day calls attention to the critical importance of uniform, accurate, traceable measurements in all aspects of the global experience. This year’s theme focuses on “Measurements supporting the global food system” which is in direct response to the challenges we face trying to produce enough safe food to reach a global population of 8 billion people.

Multi-product calibrator plus reference multimeter expands your workload

Elevate lab precision: Combine 5560A Calibrator, Reference Multimeter, Transconductance Amp, MET/CAL & Fluke Premium Care for top-tier accuracy, automation & reliability. Consult our specialists today.

Pharmaceutical Industry Resource Center - Facility Maintenance

Precision Infrared Calibrators Resource Center

Remembering John Fluke Sr.—three decades later

This video includes reminiscences from Fluke and Fluke Calibration associates who remember what it was like to work at Fluke ”back in the day.”

Safety standards and calibration

Calibration improves safety. Learn how global safety standards and safety features in Fluke calibration tools keep lab environments and workers safe.

Seeing what can't be seen in a triple point of argon system

The triple point of argon (83.8058 K ) is one of the most commonly used fixed points for the calibration of standard platinum resistance thermometers (SPRTs) at temperatures below 273.16 K. It’s a defining fixed point of the International Temperature Scale of 1990 (ITS-90). Fluke Calibration recently designed a new Triple Point of argon system with the goal in mind of achieving both efficiency and accuracy in calibrating SPRTs.

Six reasons why a pressure controller/calibrator might be the right solution for your pressure calibration application

Read more about why you a pressure controller/calibrator fits the needs of your pressure calibration calibrator and watch our vide about the 6270A Pressure Controller/Calibrator.

Steps to determine if the size of your source is too small

Knowledge of size of source is important for your infrared thermometer calibration. You should use this knowledge in determining a proper size for the thermal radiation source used for the calibration. The three methods to study the amount of source are listed below. Field-of-view Test Field-of-view Specification Sweep

The Difference Between Intermediate Checks per ISO 17025 (AKA “verification”) vs Calibration—Plus Tips for Incorporating Intermediate Checks to Help Save You from Costly Manufacturing Recalls

Learn about intermediate checks per ISO 17025 (AKA “verification”) vs calibration. Plus, tips for incorporating them to prevent costly manufacturing recalls.

The Reference Multimeter and Ratio Measurements

The Two Worlds of Radiometric and Radiation Thermometer Calibration

What is the difference between the radiometric calibration they speak of and the radiometric calibration I speak of when referring to radiation thermometry? In some aspects, I can answer this by saying “Nothing.” However, I could also answer this by saying “Everything.”

Thermocouple Application Note Series

Thermocouples are broadly used in many industrial and scientific applications. But it can be a bit tricky to understand how they work and how to calibrate them.

Thermocouple calibration: what you need to know

Learn how thermocouples work & how to choose calibration equipment, calculate uncertainties, and calibrate thermocouples. Read here and watch the video.

Tips to navigate Fluke Calibration support

Get the quickest answers and fixes when calibration software errors pop up.

Understanding the Importance of Traceability to the SI

Consider if your company would be best served by specifying traceability to the SI instead of to your local NMI.

Uses for the 52120A Transconductance Amplifier outside of the lab

What can you use a Fluke transconductance amplifier to do in addition to calibration? Accurately supply AC & DC current, overvoltage sensing, and more.

Yes you can give a great presentation at NCSLI or MSC

Whether you’re speaking to a small group of colleagues at your company or a group of professionals at MSC or NCSLI, here are some tips to help you succeed – and perhaps even enjoy your experience as a public speaker.

Yes, you can write that technical paper

Writer’s block isn’t limited to metrologists, of course – it’s a universal problem that people in many professions face (even writers). Here are a few simple tips that can help you on your way to greater visibility and respect in your career.

2015 World Metrology Day Message

Read this short blog post to see how Fluke Calibration contributes in this year's World Metrology Day theme, “Measurements and Light”.

7 important facts you must know before calibrating a clamp meter

A clamp meter typically requires an annual calibration to ensure that it continues to make measurements within the manufacturer’s specifications..

7109A Calibration Time Savings Estimate

A typical 3-point calibration of 4 tri-clamp sanitary sensors takes over 4 hours (259.45 minutes) using a 7103 Micro-Bath. The same calibration using a 7109A Portable Calibration Bath takes about 2 hours (130.0 minutes). That’s a time savings of more than 2 hours per 4-sensor batch!

A Proposal for a Standard Calibration Data Format

In 2012, the Association of German Engineers developed VDI/VDE-2623, which defines and establishes a Calibration Data Exchange Format. VDI/VDE-2623 establishes a rigid Extensible Markup Language (XML) data structure with both required and optional fields

Calibration Equipment Manufacturers: 10 Things to Look for Before You Buy

Looking to purchase a calibrator from a calibration equipment manufacturer? Grade them with these 10 criteria to make sure you get the best return on investment.

Getting started in pressure calibration: a guide to breaking down the barriers

If you are currently outsourcing or turning away pressure calibration business, you may be doing so unnecessarily. The barriers to enter the pressure calibration business can be overcome fairly easily.

High-pressure calibration and characterization in a production process

In this Fluke app note, discover the considerations of high-pressure calibration & characterization when manufacturing pressure measurement devices.

How often should you calibrate?

While there’s no “one size fits all” answer, see this post for helpful guidelines on how often you should calibrate thermometers, test equipment, multimeters, etc.

How to calibrate pressure dial gauges using cardinal point calibration

When calibrating a dial gauge, it can be challenging to interpret readings when the pointer is between marks. Learn how to overcome the challenge here.

How to simplify maintenance of a HART pressure transmitter

Complete maintenance of a HART transmitter involves three distinct operations: configuration, calibration, and adjustment. Learn more here.

Manual approach to test a pressure switch

In manually testing a pressure switch, calibrators can save you time by reducing steps, automating, & reducing the amount of equipment you need. Learn more.

Memo on the traceability, calibration, and recalibration requirements for Fluke coils

It is a well-established practice in calibration laboratories to use current coils for clamp meter calibrations. Many laboratories either build their own coil, or simply make several loops of a test lead for the purpose of increasing the current value sensed by the clamp meter

Opportunities to learn about calibration and metrology

calibration education, metrology education, web seminars, software user groups, application notes, learn about calibration, learn about metrology

Resource Centers

Fluke Calibration produces the broadest range of electrical, RF, temperature, pressure & flow calibration instruments & software that help measurement professionals around the globe.

Shopping for a multi-product electrical calibrator: Seven things you must consider

How do you choose a multi-product electrical calibrator? They are not all the same. Read this short blog post to learn seven essential points to consider.

The 9144 Field Metrology Well has replaced the 9141 Dry-Well

Fluke Calibration produces the broadest range of electrical, RF, temperature, pressure & flow calibration instruments & software that help measurement professionals around the globe.

Thermocouple Fundamentals: App Notes Series, 1 of 4

What is a thermocouple? How does a thermocouple work? Why do thermocouples need to be calibrated?

Three Common Causes of Calibration Problems

What knocks a digital instrument out of calibration? Learn about the 3 main causes of calibration problems: component shift, drops & overloads.

Three Surprising Features of the 8588A Reference Multimeter

See how Fluke’s long-scale DMMs enable digitizing with emulation, characterization of non-repetitive waveforms & lighted connection terminals. Learn more.

Two free best practice guides and the "Stik" Thermometer data sheet

Best practices that apply to any thermometer calibration

Understanding the basics of digital multimeter calibration

See the steps for how to calibrate a digital multimeter, plus links to 5 free related learning resources including videos, webinars, and articles.

Verifying process gauges, analog and digital

Both analog & digital process gauges need to be regularly verified. See the options for verifying in the field or at the bench & the steps to follow.

What matters in custody transfer: 5 ways to ensure precise measurements

See 5 ways to ensure precise measurements in oil & gas custody transfer & see how one calibrator can calibrate the involved pressure & temperature transmitters.

AC versus DC: The Truth

The purpose of this paper is to truthfully answer various questions one might have with regard to resistance bridges and readouts after reading some of the sales hype arguing that AC is better than DC or vice versa

Platinum Resistance Thermometers (PRT)

A platinum resistance thermometer (PRT) is a thermometer constructed from a high purity platinum element (wire-wound coil or thin film) placed in a tube of metal or glass and sealed with an inert atmosphere and/or mineral insulator.

PPC4 Cockpit Sample Run Windows

Primary Standards Selection Guide

Fluke Calibration manufactures leading primary temperature standards including ITS-90 SPRTs, ITS-90 fixed point cells, water triple point cells, & maintenance apparatus. Learn more.

Thermometer Probe Selection Guide

Fluke Calibration manufactures platinum resistance thermometers, thermocouples, thermistor temperature sensors for precision temperature measurement and calibration

Thermometer Readout Selection Guide

Precision thermometer readout from Fluke Calibration is easy to use, very accurate, and designed for calibration. Contact us today for more information.

To what extent can the calibration process be automated?

Automation of the pressure calibration process has many potential benefits, including increasing productivity, ensuring better pressure measurements

What is the accuracy/uncertainty of the device to be tested?

The first step to selecting the right pressure calibration product is to understand the specifications of the device under test (DUT).

What is the environment in which the calibration is to take place?

Once you know which categories of instruments will meet your measurement performance needs, you can determine which of those instruments can be used effectively in your environment.

Why buy Primary Standards from Fluke Calibration?

Fluke Calibration’s fixed-point cells benefit from more than 20 years of experience in research, design, and manufacturing. Four types of cells are available: traditional size cells, “mini” quartz cells, new “mini” metal-cased cells, and small stainless steel “X” cells

Why Calibrate Test Equipment?

Why calibrate test equipment? What makes it go out of cal? What happens when you send equipment for calibration? When should you calibrate? Learn here.

Why Calibrate?

Organizational goals are translated into manufacturing/ process requirements. Increasingly individuals and organizations depend on others to meet those requirements, and the tools they use may not all be compatible

Why Use an Annealing Furnace?

Why Use Fluke Calibration Metal Freeze-Point Cells?

See a full list of Metal Freeze-Point Cells produced by Fluke and learn more about them here.

5 Steps to Calibrate an RTD

Calibration

Calibrator: A Comprehensive Introduction

How to Calibrate a Digital Thermometer with a Dry-Block Calibrator and with Freezing and Boiling Water

How to Calibrate a Pressure Gauge with the Fluke 8270A High-Pressure Controller Calibrator

Infrared Thermometer Calibration - A Complete Guide

Temperature calibration: Tips and tricks from the real world

Three methods for calibrating temperature sensors: pros and cons

Why is Calibration Important?

What is the HART protocol?

2 guidelines to make sure the pressure calibration equipment you're buying fits your needs

If you are purchasing a calibrator to calibrate pressure measurement devices, follow these 2 simple steps to ensure you get what you need.

6 ways to maximize instrumentation calibration success

To minimize plant downtime and keep operations up and running, follow this guidance to ensure smooth instrumentation calibration.

Best Benchtop Multimeter – Most stable & accurate

See why Roger Pineche, Director of Engineering at Fluke, says the new 8588A and 8558A are the best benchtop multimeters in terms of stability & accuracy.

How to Accurately Calibrate a Hygrometer

Get step-by-step instructions on how to accurately calibrate a hygrometer or other humidity sensor including why it’s important, techniques, and tips.

Why buy Fluke Calibration?

Here are some of the most important reasons for you to consider a purchase from Fluke Calibration.

Why use calibration software in process instrumentation?

How to perform a pressure leak test using the Fluke 729 Automatic Pressure Calibrator

How to connect a Fluke 729 Automatic Pressure Calibrator to a HART Transmitter

How to Calibrate a Pressure Switch Using the Fluke 729 Automatic Pressure Calibrator

How to calibrate a HART Pressure Transmitter from a downloaded task with the Fluke 729

How to overcome pressure leaks during calibration by using the Fluke 729 Automatic Pressure Calibrator

Measurement for Health | World Metrology Day 2021

Using a mA source for testing 4 to 20 mA loop devices

How calibration improves optimization

Learn which calibration tools are best for improving optimization and quality in process manufacturing plants including chemical processing, nuclear power, pharmaceutical, pulp and paper.

How to calibrate a temperature sensor in the field

Pairing a Fluke dry well with a handheld documenting calibrator allows for a complete field temperature sensor calibration solution.

How to keep control valve positioners on target

Learn how to avoid calibration drift on control valve positioners as part of your preventive maintenance program.

Calibrating at the bench with a pressure comparator

A pressure comparator is a convenient instrument for bench pressure calibration. Bench calibrations are performed to maintain reference conditions and to obtain the lowest possible uncertainties. The bench is also a convenient place to inspect, adjust, and repair the devices under test.

Manual approach to pressure switch testing

Calibrating at the bench with a deadweight tester

A deadweight tester is a proven method of pressure calibration that is usually chosen for bench applications when accuracy and reliability are the top requirements. Calibrations are performed at the bench for convenience and to maintain reference conditions.

Hand pumps and pressure test gauges for field pressure testing

It's important to select the proper pump and gauge to match the testing application at hand—a good guideline is the testing device should be 4-10 times more accurate than the device being tested.

Calibrating a HART Smart Pressure Transmitter

Verifying and documenting the performance and adjusting a HART smart pressure transmitter can require a bucket full of tools. Performing this task with a HART enabled calibrator like the Fluke 754 simplifies the task and reduces what you need to carry.

Automating Temperature Calibration at the Bench

See the advantages of automating temperature calibration, different ways to achieve automation, and the general steps required. Plus, see related resources.

Automating Transmitter And Sensor Calibrations

Temperature transmitter calibration

Calibrating and Testing RTD Sensors

How to troubleshoot fieldbus signals

Troubleshooting a 4-20 mA loop using mA Simulate

Using loop power for process instrument and 4-20 mA loop testing

Pressure transducer calibration

Fluke experts show you how to calibrate a pressure transducer including a step-by-step pressure transducer calibration procedure, certificate, and tips.

Verifying portable thermometers

On-the-spot temperature checks using portable thermometers are frequently performed in the field by technicians in order to ensure product quality.

Simulating thermocouples and RTDs for calibration and testing

Temperature Switch and Controller Testing in the Field

A new control valve testing process

Proportional smart control valves play critical roles in process industries. Accurately assessing valve performance, however, can be a cumbersome routine.

What matters in custody transfer

How to Perform a Pressure Calibration Using the Fluke 729

Verifying analog and digital pressure gauges

How to perform a verification test on analog vs digital pressure gauges. Both analog and digital process gauges need to be verified to detect errors related to drift, environment, electrical supply, addition of components to the output loop, and other process changes

Gas custody transfer flow computer calibration

Gas custody transfer flow computers that calculate flow in pipelines by measuring the differential pressure across a flow restriction, such as an orifice plate or other differential pressure flow device, require special calibration to perform at optimum accuracy.

Documenting approach to pressure switch testing

Best accessories to set up a pressure calibration

Case study: How a power facility reduced 40% of calibration time

Many facilities, such as power plants or production facilities, depend on a strong preventive maintenance program. These programs are essential to keep processes running safely and efficiently.

Reduce instrument maintenance costs by 40% or more with route-based work flows

Glossary of Pressure Calibration Terms

Glossary of Pressure Calibration Terms

Glossary of Loop Calibration Terms

Glossary of Loop Calibration Terms

What is a 4-20 mA current loop?

Why does this year have an extra second?

On December 31, 2016, metrologists around the world—especially those living under Greenwich Mean Time (GMT)— will add a single second to their New Year's Eve countdown.

Why IR accuracy and traceability are critical

Whether you're building automobiles or electronic components, processing food, maintaining electrical systems, or making plastic, temperature inspection using infrared (IR) cameras and spot thermometers is becoming one of the quickest, safest ways to accurately inspect electrical, electronic, mechanical, HVAC, and process control systems.

Case study: Yuenglings toolbox

What's in your toolbox? Yuengling Tampa Brewery

Case study: Yuengling Brews Up a Winning Maintenance Approach

The Yuengling maintenance team keeps the vintage facility brewing and bottling up to a million barrels of beer yearly. It takes a very lean operation to win against mega-brewers many times Yuengling's size.

NIF Brings Star Power to Earth

You could call this a factory, but you've never seen a plant like this before. The "manufacturing" process here relies on "shots" of laser energy focused on a target the size of a BB. The product: a nuclear reaction six times hotter than the core of the sun . . . and a growing understanding of fusion reactions that could one day free the planet from dependence on dwindling fossil fuels. "

4-20 mA applications by FlukePlus members

Fluke customers share their tool-tips for the 4-20 mA.

Guide to signal conditioning

Learn signal conditioning basics, types of signal conditioning and how they ensure signal measurement accuracy.

Calibrating pressure transmitters and switches in potentially explosive atmospheres

Pressure calibration can be challenging in the best of environments. Working in an area that has the potential for explosion takes the degree of difficulty to another level—one where the technician needs proper training and equipment.

Assessing control valves and their performance

When assessing control valves and their performance, you need to understand the different types of valves and what they can be tested for.