Inst ToolsInst ToolsInst Tools
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
  • Request
Search
  • Books
  • Software
  • Projects
  • Process
  • Tools
  • Basics
  • Formula
  • Power Plant
  • Root Cause Analysis
  • Electrical Basics
  • Animation
  • Standards
  • 4-20 mA Course
  • Siemens PLC Course
Reading: Identify Level Control Loop Tuning Problems
Share
Font ResizerAa
Inst ToolsInst Tools
Font ResizerAa
  • Courses
  • Design
  • PLC
  • Interview
  • Control System
Search
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
  • Request
Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Inst Tools > Blog > Control Systems > Identify Level Control Loop Tuning Problems

Identify Level Control Loop Tuning Problems

Last updated: July 28, 2019 11:43 am
Editorial Staff
Control Systems Practical Questions
1 Comment
Share
2 Min Read
SHARE

A level control loop is supposed to maintain a constant level of liquid at the bottom of the stripping tower where considerable amount of vibration exists, but it seems to have a problem:

Contents
Level Control LoopAnswer :

Here is what the trend recording from Level Transmitter looks like during the time an operator placed the controller in manual mode and then back to automatic mode:

Level Control Loop

Identify Level Control Loop Tuning Problems

A fellow engineer tells you he thinks the controller is over-tuned (having too much gain). The operator, who just did the manual-mode test, disagrees.
Based on the information seen in the trend, what do you think the source of the oscillation is, and how would you go about testing your hypothesis?

Answer :

This oscillation is clearly not the result of an over-tuned controller, because it persists even when the controller is in manual mode. The source must be coming from somewhere else in the process.

At this point in time, it would be a good thing to note the frequency of this oscillation, and begin searching for anything that could cause the level to go up and down at this frequency, or perhaps something that could “fool” level transmitter (LT) into thinking the level is oscillating at this frequency. If the frequency is relatively high, local machine vibration could be the cause of it.

This hypothesis makes a lot of sense, based on the fact that the controller’s action in automatic mode doesn’t seem to be correcting the oscillations at all: the oscillation amplitude seems to remain unchanged between automatic and manual modes.

This is what we might expect from a vibration-induced oscillation, where the frequency of the oscillation is much faster than the liquid level can possible change, and therefore faster than the level control system can physically compensate.

Share Your Comments …

Articles You May Like :

Control Loop Questions

Safety Instrumented Systems

4-20mA Loop Power Supply

Feedback Control Loop

PLC Automatic Irrigation

Don't Miss Our Updates
Be the first to get exclusive content straight to your email.
We promise not to spam you. You can unsubscribe at any time.
Invalid email address
You've successfully subscribed !

Continue Reading

PID Controller Theory
Automation System Process Functionalities
Define Normal Status of a Process Switch ?
Difference Between Serial and Parallel Communication
Calculate the Magnitude of Hydrostatic Pressure
Is it Possible to Measure Liquid-Liquid Level Interface using Float?
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
1 Comment
  • Undefined says:
    April 9, 2019 at 12:11 pm

    how does the vibration can change the PV. @ i am having a flow transmitter which goes for 24 tph for 3 min and then comes to 21 tph , what could be the reason

    Reply

Leave a Reply Cancel reply

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

Stay Connected

128.3kFollowersLike
69.1kFollowersFollow
210kSubscribersSubscribe
38kFollowersFollow

Categories

Explore More

Programmable Logic Controller (PLC) Questions and Answers – 4
PLC Practice Questions
Most Asked Questions on SCADA with Answers
Commissioning Documents for Instrumentation Engineers
Boiler Drum Level Control Systems
Liquid Level Switch Control Pump and Lamp
Demo of a SCADA Software – Level Control System
What is Open Telemetry? – Principles and Benefits

Keep Learning

Identify the Pressure Gauge Error

Identify the Pressure Gauge Error

How to troubleshoot the PLC Hardware faults

Hardware Troubleshooting Steps for PLC Automation Systems

Find the Fault in the Temperature Loop

Fault in the Temperature Loop

Technical Evaluation for DCS and ESD - Distributed Control System

Technical Evaluation for DCS and ESD – Distributed Control System

PlantPAx Select Add components into Project

How to Import PlantPAx Library?

Wellhead Control Panel

Basics of Wellhead Control Panel (WHCP)

Identify Instruments in Piping and instrumentation Diagram

Identify Instruments in Piping and instrumentation Diagram

DCS Vs PLC

DCS versus PLC Architecture

Learn More

PLC 1 Push Button to Turn ON or OFF 1 Output

PLC 1 Push Button to Turn ON or OFF 1 Output

DP Transmitter Capillary arrangement

DP Transmitter Interface Level Measurement Principle, Limitations, Selection, Installation, Design & Calibration

Left-Hand Rule for Generators

Starting of DC Motors

Automobile Engineering Projects

220+ Automobile Engineering Projects

Difference between Availability, Reliability & SIL

Difference between Availability, Reliability & SIL

Calculate Hydraulic System Fluid Pressure

Calculate Hydraulic System Fluid Pressure

Wet Dust Suppression system

Wet Dust Suppression System

Feedback Characteristics of Control Systems

Control of the Effects of Disturbance Signals by Use of Feedback

Menu

  • About
  • Privacy Policy
  • Copyright

Quick Links

  • Learn PLC
  • Helping Hand
  • Part Time Job

YouTube Subscribe

Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Welcome Back!

Sign in to your account

Username or Email Address
Password

Lost your password?