What is GSD file?

What is GSD file?

WHAT IS GSD FILE? The functionality of a PROFINET IO device is defined in GSD files. This file contains all the data necessary for its communication with the IO controller. PROFINET IO devices are described using XML-based GSDML files. “GSDML” …

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What is Profinet Communication?

What is Profinet Communication? Profinet is an Ethernet-based communication protocol that adheres to industrial standards. It is widely used in the manufacturing world for machine automation or process automation, where a response time below 100 ms is required. Mainly for …

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What is MQTT>

WHAT IS MQTT? MQTT stands for “Message Queuing Telemetry Transport. MQTT protocol was indeed developed by Dr. Andy Stanford-Clark of IBM and Arlen Nipper of Arcom (now part of Eurotech). MQTT is a lightweight and straightforward communication protocol primarily designed …

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Relay Output in PLC?

Relay Output in PLC? Relay outputs are extensively employed in the manufacturing industry to control the activation and deactivation of slow-switching devices, such as motors, valves, and pumps. Since relay switching is mechanically based, its response time is slower compared …

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Categories PLC

PLC Transistor Type Output

Sink and Source Output

What is PLC Output Types? Relay Type and Transistor Type Transistor Divided Into Sink and Source Output Type 1.Sink Output Type: ( -ve common) The Sink Output type module requires a negative (-ve) common connection. When output Y is on …

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PLC Hardware Component’s?

PLC Hardware Components

PLC Hardware Components? 1.Power Supply 2.CPU: Central Processing Unit (Processor) 3.Base Rack or Chassis 4.Input Module 5.Output Module In this article, I will offer a comprehensive explanation of PLC hardware, using Rockwell PLCs as an illustrative example. 1.Power Supply: A …

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What is Power Supply in PLC?

What is Power Supply in PLC? A power supply is essential for providing power to all hardware components, including the CPU, input/output modules, and any other hardware such as communication modules, mounted on the chassis or base rack. The selection …

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What is VFD?


In this article we will learn ….

What is VFD?

Use of VFD in manufacturing world.

Advantages of VFD?

VFD stands for “Variable Frequency Drive”.

It is an electronic device designed to control the speed of a motor by varying the frequency and voltage supplied to the motor. It is mainly used to drive Induction Motors and is commonly referred to as AC drives or Inverters.

VFD’s main task is to change the power supply frequency in order to adjust the speed of the motor.

The supply voltage and frequency supplied to the VFD are fixed (typically ranging from 50 Hz to 60 Hz). The VFD then smoothly varies the frequency to adjust the motor’s speed.

Rotational Speed of Motor is calculated with following formula.

Rotational Speed of =          120* Supply Frequency [Hz]     * (1-S) [rotation/min]
Motor                                No of Poles                          
  1. When motor is stopped S is 1.
  2. No. of Poles depend on Motor configuration-4p means 4 pole motor.
  3. S=Slip-During rated speed S is 0.03 or 0.05.

Application in Manufacturing Industries

1.Damper Control

  • Airflow speed of the motor is controlled using a Variable Frequency Drive (VFD).

2.Screw Conveyor

  • In this Screw Conveyor application, a VFD is used to control the flow of material in the hopper.
  • Adjusting the speed of the motor controls the flow of material.

3.Conveyor Application

Nowadays, VFDs are mostly used in Conveyor Applications.

  • For Bottle filling applications, conveyors are used to transfer bottles. To ensure a smooth start and stop of the conveyor, an inverter is used here.
  • They are also used to improve operating efficiency by adjusting the speed as required.
  • There are thousands of applications where VFDs are used, ranging from handling small machines to managing the processes of large plants.
Categories PLC


What is Scan Time of PLC?

PLC scan time is the time taken by the PLC to scan the inputs, execute the operation logic, and generate the outputs for one cycle. This process occurs in a continuous loop. Higher the number of steps in a PLC program, the more time it will require to complete each scan. PLC scanning works from left to right and top to bottom in the program’s logic.

“For high accuracy and fast machines, a low scan time is required. Typically, PLC scan times range from 0 to 500ms, with a scan time below 100ms considered good. Higher-end PLCs generally have lower scan times.

lower scan time is indicative of a better-performing PLC, while a higher scan time suggests a less efficient or worse-performing PLC.

Instructions become more complex, their execution takes longer, leading to an increase in the scan time of a PLC.

Steps of Scan Time...

  1. When the PLC is powered ON, it first performs a diagnostic check on module configuration and parameter settings. It verifies that all hardware modules are connected and correctly configured in the program.
  2. After the diagnostic check, the PLC scans all hardware inputs to check their status. Based on the program logic, it then executes the program and updates the output status in the output map of the PLC.
  3. After that, the PLC performs communication-related tasks.
  4. And it performs another diagnostic check.

If PLC In fault state (Diagnostic function of PLC)

  • It puts the outputs into a safe state, turning all of them off.
  • And the PLC waits for the fault to clear.

PLC scanning is performed in four steps.


  • The application program is executed based on the status of inputs.


  • In the Input Scan, the PLC reads the actual inputs and transfers the image to the input image for processing.


  • The PLC reads the output processed by the CPU and updates the actual output.


Categories PLC

Block Diagram of PLC

Block Diagram of PLC Above is Block diagram of PLC. Devices connected to input side is called as Input devices like Limit Switch, Select switch, Push Button and Sensors. And output devices connected to output side. Output devices are motor, …

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Categories PLC