Automated Guided vehicle automation in the PLC

Automated Guided vehicle automation in the PLC

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D Flip Flop PLC Ladder Logic

D Flip Flop PLC Ladder Logic

D flip flop in PLC.Learn how to implement D flip flop in PLC.

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PLC program for latching and unlatching circuit

PLC Level Control of Two Tanks

The Art of Balance: PLC Level Control for Two Tanks

In many industrial processes, maintaining a consistent liquid level in a tank is critical. Whether it's for mixing chemicals, ensuring a continuous supply to a production line, or managing wastewater, a simple overflow or dry-run can lead to costly downtime and safety hazards. A Programmable Logic Controller (PLC) is the perfect tool for this job, using a simple and reliable logic to automate the process. This article explains how a PLC system can be configured to control the liquid level in not one, but two interconnected tanks.

The Challenge: Keeping Two Tanks in Sync

Imagine a system with two tanks, Tank A and Tank B, where Tank A fills Tank B. If Tank B is allowed to overflow, it creates a spill, but if it runs empty, the downstream process stops. The goal is to design a control system that uses a pump and a valve to maintain the liquid level within a safe operating range in both tanks. The complexity lies in managing the flow between the tanks to prevent either a dry-run or an overflow condition.

Key Components of the System

A PLC-based level control system relies on a few core components to function:

Level Sensors: These are the "eyes" of the system. For a two-tank setup, you would typically use two sensors per tank.

 For example:

• • High-Level Sensor (HLS): A sensor placed at the top of the tank to detect when the liquid has reached the maximum safe level.

  • Low-Level Sensor (LLS): A sensor placed near the bottom of the tank to detect when the liquid is running low.

• Actuators: These are the devices that perform the physical work. In our example, this would be a pump and a valve.

  • Pump (P1): Fills Tank A from a source.

  • Valve (V1): Controls the flow from Tank A to Tank B.

• Programmable Logic Controller (PLC): The "brain" of the system. It receives signals from the level sensors and sends commands to the pump and valve based on its programmed logic.

The Control Logic: A Simple But Effective Solution

The logic for this system is designed to be fail-safe and efficient. It can be broken down into a few simple rules:

Rule 1: Filling Tank A

• The PLC continuously monitors the low-level sensor in Tank A.

• IF the Tank A Low-Level Sensor (LS1) is OFF (meaning the tank is not low), THEN the PLC keeps the pump (P1) OFF.

• IF the Tank A Low-Level Sensor (LS1) is ON (meaning the tank is low), THEN the PLC turns the pump (P1) ON to start filling the tank.

• The pump will continue to run until the Tank A High-Level Sensor (HS1) turns ON. When this happens, the PLC turns the pump OFF.

Rule 2: Filling Tank B

• The PLC monitors the level sensors in Tank B and also checks the level in Tank A to ensure there is enough liquid to transfer.

• IF the Tank A Low-Level Sensor (LS1) is OFF AND the Tank B Low-Level Sensor (LS2) is ON, THEN the PLC opens the valve (V1). This allows liquid to flow from Tank A to Tank B.

• IF the Tank B High-Level Sensor (HS2) turns ON, THEN the PLC closes the valve (V1) to prevent overflow.

By programming these simple conditional statements, the PLC creates an automated system that keeps both tanks at a stable level. The logic ensures that Tank A always has enough liquid to supply Tank B and that Tank B never overflows.

Automatic Mixing Controlling in a Tank

 Automatic mixing controlling in a tank.Learn how to write PLC program for this application.

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Counting Moving Objects on Conveyor.

PLC Program for Counting Moving Objects on Conveyor.

This is PLC Program to implement program for counting of objects on the moving conveyor.

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Example:-ON/OFF PLC Output with Switch

Example:-ON/OFF PLC Output with Switch 

Explanation:-

When Start switch (SW1) will be pressed then Output (Lamp 1) will be on and Output (Lamp 1) will be turned off if switch will be turned off.

Program: - Write the ladder Logic for above application.

Input List:

Start Switch-I0.0

Output List:

Lamp 1 -Q0.0

Count and Pack Objects from Conveyor

Food Processing Industry.

Draining Same Products from Two Tanks

Drain Same Products from Two Tanks

Drain same products from two tanks in idustry. Learn how to write PLC program for this application.

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Automatic light blinking on 2s interval using PLC.

Automatic light blinking on 2s interval using PLC.

This is PLC Program for the automatic light blinking on 2s interval using PLC.

Problem Description

We need to light ON/OFF at 2 sec interval. Write the PLC for gram for this application using ladder diagram language.

Problem Diagram

Problem Solution

This problem can be solved by PLC logic. We can use timer instruction for this logic.

For explanation consider one switch for enabling the ON/OFF cycle and consider one lamp for monitoring.

When the user starts the cycle lamp will be ON and after 2sec delay it will be OFF automatically. This cycle runs continuously till start switch is pressed.

Program

Here is PLC program for the automatic light blinking on 2 sec interval using PLC.

List of Inputs/Outputs

Inputs List:-

ON/OFF SW =I0.0

E STOP:-I0.1

Outputs List:-

Light:-Q0.0

M Memory:-

M1.0=bit memory for lamp OFF command.

Ladder diagram for the automatic light blinking on 2 sec interval using PLC.

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Program Description

In network 1 when ON/OFF SW (I0.0) is pressed and lamp OFF command is not present then light (Q0.0) will be ON. So here we are using NO contact of ON/OFF SW (I0.0) and NC contact of light OFF condition (M1.0).

In this network once lamp (Q0.0) is ON then TON (ON delay timer) instruction is going to be executed and it'll set the lamp OFF condition. Therefore we've taken here NO contact of light (Q0.0), TON timer and programmed time 2s.

As per our condition light OFF condition (M1.0) ought to be OFF once 2s delay therefore we've got used TON once more. Therefore we tend to use NO contact of light OFF condition (M1.0) and TON with 2s programmed time.

E stop button is used for emergency stop cycle if any fault occur.