Inst ToolsInst ToolsInst Tools
  • Ask
  • Courses
  • Videos
  • Q & A
    • Interview
      • Instrumentation
      • Electronics
      • Electrical
      • Practical Questions
    • MCQ
      • Instrumentation MCQ
      • Electrical MCQ
      • Electronics MCQ
      • Control Systems MCQ
      • Analog Electronics MCQ
      • Digital Electronics MCQ
      • Power Electronics MCQ
      • Microprocessor MCQ
      • Multiple Choice Questions
  • EE
    • Electronics
      • Electronics Q & A
      • Electronic Basics
      • Electronic Devices & Circuits
      • Electronics Animation
      • Digital Electronics
    • Electrical
      • Electrical Basics
      • Electrical Q & A
      • Power Electronics
      • Electrical Machines
      • Electrical Animation
      • Power Systems
      • Switchgear & Protection
      • Transmission & Distribution
  • Measure
    • Control Valves
    • Calibration
    • Temperature
    • Pressure
    • Flow
    • Level
    • Analyzers
    • Switches
    • Vibration
    • Solenoid Valve
  • Control
    • PLC Tutorials
    • Control Systems
    • Safety Instrumented System (SIS)
    • Communication
    • Fire & Gas System
  • More
    • Design
    • Tools
    • Animation
    • Basics
    • Formulas
    • Standards
    • TextBooks
    • Common
    • Software
    • Excel Tools
    • Erection & Commissioning
    • Process Fundamentals
    • Videos
    • Books
Search
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Reading: What is a Dry Contact? – Basics of PLC Wiring
Share
Notification Show More
Font ResizerAa
Inst ToolsInst Tools
Font ResizerAa
  • Courses
  • PLC Tutorials
  • Control Systems
Search
  • Ask
  • Courses
  • Videos
  • Q & A
    • Interview
    • MCQ
  • EE
    • Electronics
    • Electrical
  • Measure
    • Control Valves
    • Calibration
    • Temperature
    • Pressure
    • Flow
    • Level
    • Analyzers
    • Switches
    • Vibration
    • Solenoid Valve
  • Control
    • PLC Tutorials
    • Control Systems
    • Safety Instrumented System (SIS)
    • Communication
    • Fire & Gas System
  • More
    • Design
    • Tools
    • Animation
    • Basics
    • Formulas
    • Standards
    • TextBooks
    • Common
    • Software
    • Excel Tools
    • Erection & Commissioning
    • Process Fundamentals
    • Videos
    • Books
Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Inst Tools > Blog > PLC Tutorials > What is a Dry Contact? – Basics of PLC Wiring

What is a Dry Contact? – Basics of PLC Wiring

In this article, we will understood the basic concept and wiring of a dry contact in PLC, and their advantages & disadvantages.

Last updated: April 1, 2022 9:03 am
Editorial Staff
PLC Tutorials
No Comments
Share
4 Min Read
SHARE

In this post, we will understand the concept of a dry contact in PLC and understand its wiring.

Contents
What is a Dry Contact?Advantages of Dry ContactRead Next:

In PLC electrical wiring, understanding the concept of contact switching and wiring is important for operation. A circuit is completed when the contact is closed; so, it is important to understand the wiring and switching.

When it comes to contact wiring, basically, two types of contacts are used –

  1. Dry contact and
  2. Wet contact

It is important to note that it applies only to digital inputs and outputs; because analog is variable in nature and there is no concept of contact in it.

What is a Dry Contact?

In this post, we will understand the concept of dry contact wiring.

Dry Contact in PLC

Dry contact means a simple example of an electrical relay. The relay has a coil that when given power, operates a set of contacts at its outputs.

The contacts can be given a different potential than the potential applied at replay input. If the relay is energized by AC supply, then the contact potential to drive the load can be AC, DC, or even potential free.

This means the contacts and switching and powering the circuit irrespective of the power at its source. So, dry contact is defined as a contact in which power or voltage is not given to a circuit by a switch, but instead, given by an external power source.

In the example we discussed here, the circuit power is not supplied by the switch; it is supplied by an external power source that is applied at the contacts.

If it was to be supplied by the switch, then the relay potential which is given to energize the relay would have been directly applied to the contacts once triggered.

Basic Concepts of the Safety Relay
In Relay, the control signals are called as A1 & A2 terminals

Let us simplify it more for better understanding. A relay has 5 basic terminals – A1 (supply positive), A2 (supply negative), COM (contact common), NO (contact normally open), and NC (contact normally close).

The terminals A1 and A2 are used to energize the relay. The contact circuit is isolated from the power circuit.

When the relay is energized, the potential given at the common terminal (AC, DC, or potential free) will be given to the NO terminal.

When the relay is de-energized, the potential given at the common terminal will be given to the NC terminal.

Advantages of Dry Contact

This shows that a dry contact acts just like an ordinary switch. They are used to provide isolation between two circuits.

One main advantage is that you can completely isolate the two circuits and check one circuit if any problem arises, without touching the second circuit. If any issue arises for example on the input side, then you do not need to check and switch off the potential supply of the output side.

In this way, we understood the basic concept and wiring of a dry contact in PLC.

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

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

Read Next:

  • PLC Wiring Diagrams
  • Electrical Wiring Diagram
  • 4-20 mA Transmitter Wiring
  • Why 24 Volts DC Power Supply?
  • Interposing Relay Panel Wiring
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 !
Configuration of Profibus Network in Siemens PLC
Feedback Monitoring in Safety PLC
Light ON OFF Control using PLC
Siemens Tia Portal PLC Training Course
PLC Programming to Control Lights in a Sequence
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
Leave a Comment

Leave a Reply Cancel reply

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

Stay Connected

128.3kFollowersLike
69.1kFollowersFollow
208kSubscribersSubscribe
38kFollowersFollow

Categories

Recent Comments

  • Guifty Shimica on Top Non-PLC Certification Courses for Automation Professionals
  • Guifty Shimica on Top Non-PLC Certification Courses for Automation Professionals
  • MIHARITSOA Aina Sitraka on Top Non-PLC Certification Courses for Automation Professionals
  • Vaishnavi on Free Instrumentation Course for Trainee Engineers

Related Articles

Ccomparator in PLC Programming

Comparator in PLC Programming

PLC Examples for calling functions in SCL

How to Insert Block Calls in SCL Language?

What is Hot Standby in PLC

What is Hot Standby in PLC?

Electrical Ground Loop

How to Solve Electrical Ground Loop Problems?

PLC Programmer Tools

Tools Required for PLC Programmer to Carry at Site

PLC Programmer Unknown Do's

Unknown Do’s Need to Know as a PLC Programmer

One Shot Rising PLC Example Program

One Shot Rising PLC Example Program

Control Algorithms in PLC Programming

Control Algorithms in PLC Programming

More Articles

Conductivity Meter

How to Select a Conductivity Meter

Single Phase Earth Return System

Single Phase Earth Return System Advantages & Disadvantages

Instrumentation Inspection and Quality Control Questions

Instrumentation Inspection and Quality Control Questions

Digital Electronics Multiple Choice Questions

Liquid Crystal Display Objective Questions

Typical Purging Installation

Purging of Instruments

Water Treatment Plant SCADA

Typical HMI Screen Design for Water Treatment Plant

Displacer Type Density Transmitter

Displacer Type Density Transmitter Question

types-of-total-organic-carbon

Basics of Total Organic Carbon (TOC) Analyzers

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?