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: Types of Interlocks
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 > Types of Interlocks

Types of Interlocks

Last updated: March 4, 2021 1:07 pm
Editorial Staff
Control Systems PLC Tutorials
1 Comment
Share
2 Min Read
SHARE

Interlocking is primarily a safety measure, though, the process interlocks used to control the loops or sequence.

Contents
Interlock PhilosophyTypes of InterlocksHardwired InterlockSafety InterlockProcess InterlockPermissive Interlock

Interlock Philosophy

Interlock Philosophy

Interlocking is a method used to maintain safe operating state of machinery.

Interlocks (except process) put the ‘target device’ (the equipment which the interlock acts on e.g Valve or Pump) into a “default” position to help ensure process is in a safe state. All interlocks report to the control system.

Also Read: Shutdown Philosophy

Types of Interlocks

The types of interlocks in the System are described below.

Hardwired Interlock

These are often used as a primary safety device. The signal from the interlocked device is wired directly to the controlled device.

The signal is also input into the control program in order monitor the state.

They cannot be bypassed by the control logic, and takes priority over safety and process interlocks.

Each hardwired interlock is associated with a Priority 1 alarm.

Safety Interlock

An interlock used specifically for safety reasons. Control program operates the interlock with control logic in response to a signal input.

The interlock may only be changed or bypassed by changing the control logic.

Each Safety interlock is associated with a Priority 2 alarm.

Process Interlock

An interlock used to automate the control of a process or a device. The control program operates the interlock in response to a signal input.

The interlock is always active during Run mode.

Permissive Interlock

The interlock is only in a position other than its safe or default position if and only if certain conditions are true. In all other instances, including poor signal quality, the interlock assumes “default” position.

If you liked this article, then please subscribe to our YouTube Channel for PLC and SCADA video tutorials.

You can also follow us on Facebook and Twitter to receive daily updates.

Read Next:

  • DCS System Layout
  • ICS Control System
  • PLC Permissive Interlocks
  • Interlocking in PLC
  • PLC, HMI, VFD, and Motor
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

PLC Programming for Garden Sprinkler System
Free SCADA Software Download
Communication between Factory IO and Siemens Tia Portal
Software Redundancy in Siemens PLC – Hardware versus Software
PLC Program to Count Running Hours of any Equipment
PLC Analog I/O and Network I/O
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
1 Comment
  • Mathias udoudo says:
    February 19, 2020 at 12:50 pm

    Good one

    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

200+ Quiz on Electrical Meters, Measurement, and Troubleshooting
Override Control Functions
Cascade Temperature Control System
100 Electrical Circuit Breaker Quiz
UPS Selection Factors for a Control System
Difference between Machine Expert Basic and Machine Expert – Schneider PLC
Timers using Statement List (STL) PLC Programming
Series Tanks Level Control using PLC Ladder Programming

Keep Learning

PLC Cooking Timer Example for Kitchen Automation

PLC Cooking Timer Example for Kitchen Automation

Why Baud Rate is Important in Modbus Network

Why Baud Rate is Important in Modbus Network?

Open Systems Interconnection

What is Open Systems Interconnection?

PLC Automation Memory

What is NOR Flash Memory in PLC?

JMP instruction in PLC Programming

How to use JUMP Instruction in PLC Ladder Logic?

Use Cryptographic checks for PLC

#5 PLC Best Practices – Cryptographic and Checksum Integrity Checks

PLC Program for Forward and Reverse Motor control

3 Phase Motor Control using PLC Ladder Logic

Siemens PLC Write Protection

How to Protect Siemens PLC using Password?

Learn More

In this article, we will learn the difference between Machine Expert Basic and Machine Expert software in Schneider PLC.

Difference between Machine Expert Basic and Machine Expert – Schneider PLC

Field Instruments

Is Vacuum affects Field Instruments in Industries?

Caliper Calibration

Setting Up for Success: Preparing for Caliper Calibration

Digital Electronics Multiple Choice Questions

Hardware Description Language Objective Questions

Orifice plate with vent and drain holes

Basics of Orifice Plates

Instrumentation Cables Questions Answers

Instrumentation Cables Questions & Answers

Common Questions on Oil and Natural Gas Industry

Common Questions on Oil and Natural Gas Industry

Car Parking System using PLC Programming

Car Parking System using PLC Programming

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?