By using this site, you agree to the Privacy Policy and Terms of Use.
Accept
Automation CommunityAutomation Community
  • PLC
  • Automation
  • Instrumentation
  • Calibration
  • Electrical
  • Courses
    • Siemens PLC Course
    • Allen Bradley PLC Course
    • InTouch SCADA Course
    • WinCC SCADA Course
    • Siemens Tia Portal
    • Omron PLC Course
    • Advanced PLC Course
Search
  • Customize Interests
  • My Bookmarks
© Automation Community. All Rights Reserved.
Reading: Calibration Procedure of a Control Valve
Share
Notification Show More
Aa
Automation CommunityAutomation Community
Aa
  • PLC
  • Automation
  • Instrumentation
Search
  • PLC
  • Automation
  • Instrumentation
  • Calibration
  • Electrical
  • Courses
    • Siemens PLC Course
    • Allen Bradley PLC Course
    • InTouch SCADA Course
    • WinCC SCADA Course
    • Siemens Tia Portal
    • Omron PLC Course
    • Advanced PLC Course
Follow US
© 2023. All Rights Reserved.
Automation Community > Blog > Control Valves > Calibration Procedure of a Control Valve
Control ValvesInstrumentation

Calibration Procedure of a Control Valve

R Jagan Mohan Rao
Last updated: 2023/05/18 at 11:06 AM
R Jagan Mohan Rao
Share
8 Min Read
SHARE

What is a Control Valve?

Control valves are devices that perform the function of regulating the flow of a fluid. The control valves receive the command signals from the PID controllers in a PLC or a DCS system. The valve positioners adjust the instrument air-flow to the valve actuator as per the received signal from the PLC or DCS systems.

Contents
What is a Control Valve?Basics of Control ValveList of Tools Required for Valve CalibrationCalibration ProcedureControl Valve Calibration Procedure Without AccessoriesControl Valve with Pneumatic Positioner CalibrationControl Valve with Smart Positioner Calibration Procedure

This allows the control of the fluid flow through the valve and the consequent control of the variables of the process such as pressure, temperature, and level.

Valves are the main final control elements.

Basics of Control Valve

Control valves are classified into several types. According to the stem movement, they can be rotary or linear valves. Based on the action, they can be air to open or air to close. Based on its actuation, it can be a diaphragm or cylinder pressurized, and so on.

For a control valve that is serviced in an instrument workshop, the following steps are carried out as part of the calibration process.

List of Tools Required for Valve Calibration

  • 4-20 mA calibrator or source feeder
  • Regulator for supplying 3-15 PSI signal
  • Regulator for 20 psi supply
  • Pressure Gauge (3-15 PSI ranged)
  • HART Communicator
  • Datasheet (if applicable)

Calibration Procedure

Initially, a thoroughly serviced control valve needs to be calibrated in three stages.

  • One is valve calibration without accessories. That is stroke checking.
  • The next step is with the positioner (if the I/P converter is externally mounted).
  • The last step is a positioner with an integral I/P converter (Smart Valve Positioner).

All above-said practices differ slightly from process plant to plant as per their particular needs.

Nowadays the calibration procedure of a control valve with a smart positioner is a popular method used in industries.

Before starting the job, take proper work permits and inform the process engineers and take the isolation of the valve if required. Place the PID controller in manual mode in the PLC or DCS systems.

Step-by-step procedure:

Control Valve Calibration Procedure Without Accessories

The below calibration procedure for a control valve without accessories.

1. To start calibrating a control valve, it is important to determine its operating range, that is, if it is 3-15 PSI, or split range (3-9 PSI, or 9-15 PSI), as well as to know the type of action, whether it is air to close or air to open the valve.

2. Once the operating range and the type of valve action have been determined, a pressure simulation will be applied to calibrate it. It is nothing but a stroke test to determine the full open and full closure of a valve.

3. Now, let us calibrate a valve with 3-15 PSI, if it is a reverse action (air to open) then the valve will be closed, it begins to simulate pressure little by little and it should start opening at approx. 3 PSI. The valve travel indicator must be at 0%.

4. When we apply with 3 PSI then the valve will be at 0%. Next, we proceed to apply 15 PSI then the valve must open 100%, and the stroke indication shows full scale.

More Read

Safety PLC Interview Questions and Answers

Venturi Flow Meter and Flow Element – Instrumentation Basics

PLC Programming Questions and Answers

100 Instrumentation Interview Questions and Answers

FOUNDATION Fieldbus Devices

5. If there is a problem with the 0% and 100% calibration then proceed to adjust the spring tension nut on the control valve until achieving the desired value.

6. The verification of 0% and 100% are repeated a number of times that are necessary until the valve is correctly calibrated.

Note: the above steps have been done with a reverse-acting valve (closes no air).

The calibration of a direct-acting valve (without air opening) would be done in reverse, that is, at 15 PSI the valve should be closed while at 3 PSI it would be completely open. The open and close percentages also change inversely.

Control Valve with Pneumatic Positioner Calibration

The below calibration procedure for a control valve with a pneumatic positioner.

1. Once the control valve is calibrated without accessories installed, proceed to do it with one of them (Positioner).

2. To calibrate the automatic valve with a pneumatic Positioner, an air regulator is installed to the valve body or attached to the Positioner directly and an air supply of 20 PSI. Apply 3-15 PSI from a fine regulator and sends an opening signal to the valve.

3. With a signal of 3 PSI the valve must be at 0%. If it is not the case with the Zero screw you adjust the position of the valve so that it is closed.

4. When the positioner sends 15 PSI output to the valve actuator the valve adjusts its position to 100%. If not the case, adjust the span screw so that it gives said opening value.

5. As many times as necessary, these steps will be repeated until the valve shows correct readings i.e. open and close parameters.

6. Once the percentages of 0% and 100% have been adjusted, the intermediate values ​​will be checked.

Control Valve with Smart Positioner Calibration Procedure

The below calibration procedure for a control valve with a smart positioner. We can also call this an electro-pneumatic positioner with a control valve.

Calibration procedure of a Control Valve

1. In the calibration procedure of a pneumatic Positioner this is done mechanically and with control air.

2. In the case of an electro-pneumatic positioner, it works with a 4 – 20 mA current signal and controls air through the valve actuator.

3. To check the 0% opening of the valve, 4 mA is simulated to the electronic positioner, and this will show the valve’s 0% position. If this percentage of the opening is not achieved, then connect the HART communicator to the valve positioner and start calibration.

4. To check the 100% opening, 20 mA is simulated and this will show the valve’s 100% position. If there is some problem then connect the HART communicator to the valve positioner and then start the calibration.

5. In some control valves, you will be provided with a display and control buttons. You can use these to check the valve position status and also you can start the calibration. (no need for a HART communicator)

6. Once the percentages of 0% and 100% have been calibrated, the intermediate values also will be verified, like 8 mA -> 25%, 12 mA -> 50%, and 16 mA -> 75%.

Table of Control Valve Opening Percentages

Table of Control Valve Opening Percentages

Keywords

Air to open: The air-to-open control valve is held close by the spring force, and the pneumatic signal makes it open. Also called Reverse action.

Air to close: The air-to-close control valve requires a pneumatic signal to move towards a close position. Also called Direct action.

AFR: AFR means Air Filter Regulator. The AFR is used to adjust the required instrument air to the control valve.

You Might Also Like

DNP3 Communication – Distributed Network Protocol 3

Non-contact Pyrometer Questions and Answers

HART-IP: HART Communication over Internet Protocol

Instrumentation Insights: Exploring Safety Integrity Level (SIL)

Temperature Transmitter Questions and Answers

TAGGED: Automation

Sign Up For Daily Newsletter

Be keep up! Get the latest breaking news delivered straight to your inbox.
[mc4wp_form]
By signing up, you agree to our Terms of Use and acknowledge the data practices in our Privacy Policy. You may unsubscribe at any time.
Share This Article
Facebook Twitter Whatsapp Whatsapp LinkedIn
Share
By R Jagan Mohan Rao
An astute professional with 25 years of service as an Instrumentation Engineer, started a career in Pulp & Paper. In the course of time, shifted to Power plants, Cellulose units, Chemical plants (Carbon di Sulphide, Clo2, and Sulphuric Acid), Oil and Gas (Exploration & Production). Most of the service is in Operations & maintenance. As per demand, handled project pre-commissioning, and commissioning activities. 20 years of service in India, 5 years in Middle East nations.
Previous Article Online PLC Course Online PLC Course – Programmable Logic Controllers
Next Article How to do Calibration of Temperature Switch How to do Calibration of Temperature Switch? – Detailed Procedure
1 Comment 1 Comment
  • Mansour DIOP instrumentiste says:
    October 29, 2022 at 8:12 pm

    Pertinent… Merci

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Stay Connected

120.5k Followers Like
10.1k Followers Follow
90.6k Subscribers Subscribe

Latest Articles

SNMP_question_and_answers
SNMP Questions and Answers
Automation August 25, 2023
Zigbee_question_and_answers
Zigbee Questions and Answers
Automation August 24, 2023
Z-Wave Questions and Answers
Z-wave Questions and Answers
Automation August 23, 2023
konnex_questions_and_answers
KNX (Konnex) Questions and Answers
Automation August 22, 2023
Advantages and Disadvantages of DCS
Automation

Advantages and Disadvantages of DCS

In this article, you will learn the advantages and disadvantages of DCS…

Editorial Staff By Editorial Staff January 12, 2023
Top Essential Devices for Electrical Switchgear
Electrical

Top Essential Devices in Electrical Switchgear – List

This article provides a list of the top essential devices commonly used…

Vivek By Vivek May 3, 2023
INTERBUS - Fieldbus Communication Protocol Questions
AutomationInstrumentationPLC

INTERBUS – Fieldbus Communication Protocol

INTERBUS is a Fieldbus communication protocol used in automation systems and the…

Editorial Staff By Editorial Staff June 23, 2023
Instrumentation and Tools Multiple Choice Questions and Answers
Instrumentation

Instrumentation and Tools Multiple Choice Questions and Answers

This article presents the top instrumentation and tools Multiple Choice Questions and…

Editorial Staff By Editorial Staff May 4, 2023
Resistor Questions and Answers
ElectronicsElectrical

Resistor Questions and Answers – Basics of Electronics

Resistors are fundamental components used in electronic circuits to control the flow…

Editorial Staff By Editorial Staff July 19, 2023
Calibration Procedure of pH Meter
CalibrationInstrumentation

pH Meter Calibration Procedure

The pH meter calibration process is to be carried out in a…

R Jagan Mohan Rao By R Jagan Mohan Rao September 18, 2020
Show More
//

We provide resoucres to million users and we are the number one business and industrial automation news network on the planet

Quick Link

  • Customize Interests
  • My Bookmarks

Top Categories

  • PLC
  • Automation
  • Instrumentation

Sign Up for Our Newsletter

Subscribe to our newsletter to get our newest articles instantly!

[mc4wp_form id=”847″]

Follow US
© 2023 All Rights Reserved. Supported by Inst Tools.
login
Welcome Back!

Sign in to your account

Lost your password?