January 19, 2025

Single tank level controlling using PLC using FBD language

Single tank level controlling using PLC-FBD

 

This is PLC Program for single tank level controlling.

 

Problem Description:-

We need to control the level of water in the tank. Control the water level by simple PLC logic. Write the FBD diagram logic for this application.

Problem Diagram




Problem Solution

To solve this this example we are using PLC programming. Here we have a tendency to use 2 sensors for level measurement, one is for prime level and second is for low level.

We use feeding valve for feeding Cycle for the tank and discharge valve for discharging cycle for the tank. Each valve are controlled by sensors. So once the water level goes below low level then feeding valve can activate mechanically and water level senses the high level then discharging method are activate mechanically.

Program

Here is PLC program for single tank level controlling using PLC.

List of inputs/outputs

Digital inputs:-

Main switch:-I1.1

Start button:-I0.0

Stop button:-I0.1

High level:-I0.2

Low level:-I0.3

Feeding valve:-Q0.1

Discharge valve:-Q0.2

 

Digital outputs:-

Master coil:-Q0.0

Feeding valve:-Q0.1

Discharge valve:-Q0.2

Mixer motor:-Q0.3


FBD diagram for single tank level controlling.







Program Description


In network 1 we tend to used latching circuit for master coil ON (Q0.0) output.it will be started by pressing START Push button (I0.0) and stop by pressing STOP pushbutton (I0.1).


When cycle are going to be begin then system check level of the tank. If tank level is low then then feeding method can begin and tank level is high then Discharge cycle can begin.


Here we've taken NO contact for each sensors within the program for simplicity. It will be done by relay logic in field otherwise you will choose such variety of sensors.


In network 2,when tank can observe low level then low level sensor (I0.2) is going to be activated and feeding cycle are going to be ON. Here we've taken NC contact of high level sensor (I0.3) therefore once PLC can observe high level then it'll STOP feeding cycle.


In network 3,when tank can observe high level then high level sensor (I0.3)  is  to be activated and discharging cycle are going to be ON. Here we've taken NC contact of low level sensor (I0.2) therefore once PLC can observe low level then it'll STOP discharge cycle.

In network 4, mixer motor (Q0.3) will remain ON when discharge valve is ON.


Note:-Application is only for learning and educational purpose .Above application may be different from actual application. This application can be done in other PLC also. Users are responsible for correct operation of the PLC system and for any possible injuries and or material damages resulting from the use of this program. It is necessary to take care of safety during implementation, installation, maintenance and operation.

 

All parameters and graphical representations considered in this example are for explanation purpose only, parameters or representation may be different in actual applications. Also all interlocks are not considered in the application.

 

 

January 18, 2025

Single tank level controlling using PLC using ladder language

Single tank level controlling using PLC.

 

This is PLC Program for single tank level controlling.

 

Problem Description:-

We need to control the level of water in the tank. Control the water level by simple PLC logic. Write the ladder diagram logic for this application.

Problem Diagram



Problem Solution

To solve this this example we are using PLC programming. Here we have a tendency to use 2 sensors for level measurement, one is for prime level and second is for low level.

We use feeding valve for feeding Cycle for the tank and discharge valve for discharging cycle for the tank. Each valve are controlled by sensors. So once the water level goes below low level then feeding valve can activate mechanically and water level senses the high level then discharging method are activate mechanically.

Program

Here is PLC program for single tank level controlling using PLC.

List of inputs/outputs

Digital inputs:-

Main switch:-I1.1

Start button:-I0.0

Stop button:-I0.1

High level:-I0.2

Low level:-I0.3

Feeding valve:-Q0.1

Discharge valve:-Q0.2

 

Digital outputs:-

Master coil:-Q0.0

Feeding valve:-Q0.1

Discharge valve:-Q0.2

Mixer motor:-Q0.3

 Ladder diagram for single tank level controlling.






Program Description


In network 1 we tend to used latching circuit for master coil ON (Q0.0) output.it will be started by pressing START Push button (I0.0) and stop by pressing STOP pushbutton (I0.1).


When cycle are going to be begin then system check level of the tank. If tank level is low then then feeding method can begin and tank level is high then Discharge cycle can begin.


Here we've taken NO contact for each sensors within the program for simplicity. It will be done by relay logic in field otherwise you will choose such variety of sensors.


In network 2,when tank can observe low level then low level sensor (I0.2) is going to be activated and feeding cycle are going to be ON. Here we've taken NC contact of high level sensor (I0.3) therefore once PLC can observe high level then it'll STOP feeding cycle.


In network 3,when tank can observe high level then high level sensor (I0.3)  is  to be activated and discharging cycle are going to be ON. Here we've taken NC contact of low level sensor (I0.2) therefore once PLC can observe low level then it'll STOP discharge cycle.

In network 4, mixer motor (Q0.3) will remain ON when discharge valve is ON.


Note:-Application is only for learning and educational purpose .Above application may be different from actual application. This application can be done in other PLC also. Users are responsible for correct operation of the PLC system and for any possible injuries and or material damages resulting from the use of this program. It is necessary to take care of safety during implementation, installation, maintenance and operation.

 

All parameters and graphical representations considered in this example are for explanation purpose only, parameters or representation may be different in actual applications. Also all interlocks are not considered in the application.

 

January 17, 2025

OR Valve and Series Connection in Pneumatic Circuit

In pneumatic control systems, an OR valve is a crucial component that allows alternative flow paths for air, enabling a flexible operation of devices. The series connection of pneumatic components refers to the way components are connected in a series to perform specific sequential actions.

This article explores the OR valve and its use in a series connection within a pneumatic circuit, covering the working principles, components, and circuit designs.

What is an OR Valve?

An OR valve is a type of pneumatic valve used to create alternative flow paths. It is typically a 3/2-way valve that allows air to flow to one of two outputs based on which input is activated.

The key function of an OR valve is to select one of the available paths for airflow based on external signals. This makes it useful in circuits where different actions can be triggered by either of two inputs.

Key Characteristics of OR Valves

  • 3/2-Way OR Valve: The valve has three ports and two positions, and the flow can be directed to one of the outputs depending on the active input.
  • Control Flexibility: Allows for the combination of multiple inputs to control the same output.
  • Safety: Prevents system overload by managing the airflow paths effectively.

Working Principle of OR Valve in Pneumatic Circuit

An OR valve can be connected to either a push button or a limit switch. It ensures that air flows to the output from either of the input sources based on which is activated.

Here’s how it works:

  • Input 1 Activated: Air is directed to the output through port A.
  • Input 2 Activated: Air is directed to the output through port B.
  • If both inputs are activated, either path can be used, ensuring flexibility in system operation.

The OR valve is often used when you need to provide an alternative air path or for redundancy purposes. For example, in a cylinder actuation system, two sensors or buttons can trigger the same operation, but each has its own independent signal.

Series Connection in Pneumatic Circuit

In a series connection setup, pneumatic components (such as cylinders, valves, or limit switches) are connected one after the other, forming a sequence of operations. This method ensures that the pneumatic system operates in a controlled order, with each component activated sequentially based on the condition of the previous one.

How Does Series Connection Work?

  • Series Operation: Components in the series will operate only when the previous component is activated. For example, if multiple limit switches are connected in series, the cylinder will only extend if all limit switches are activated in sequence.
  • Sequential Control: If there is a failure or deactivation in one of the components, the entire series will be halted.
  • Common Applications: Safety systems, sequential material handling, and process automation, where conditions must be met in a specific order.

Combining OR Valve and Series Connection in Pneumatic Circuit

When combining OR valves and series connections, you create a circuit that offers flexibility and control. The OR valve ensures multiple input sources can trigger the same output, while the series connection ensures that components must be activated in a specific order.

Example: Cylinder Control Using OR Valve and Series Connection

In a system where a double-acting cylinder is used, the OR valve can be employed to allow either of two buttons (or sensors) to extend the cylinder. A limit switch could be connected in series to ensure the cylinder retracts only when the right conditions are met.

  1. Step 1: Press Button 1 (or Trigger Sensor 1)

    • The OR valve directs air to the cylinder extension port, causing the cylinder to extend.
  2. Step 2: Press Button 2 (or Trigger Sensor 2)

    • Air is directed through the OR valve and reaches the cylinder, causing it to extend even if Button 1 wasn’t pressed.
  3. Step 3: Limit Switch in Series for Retraction

    • Once the cylinder has fully extended, the limit switch in the series path activates and sends a signal to the valve to retract the cylinder.

By combining the OR valve with a series connection of components, the system becomes more adaptable, and the overall control is optimized for both flexibility and safety.

Advantages of Using OR Valve and Series Connection

  • Flexibility: The OR valve allows multiple inputs to control the same output, making it adaptable for different operational conditions.
  • Redundancy: If one input fails, the alternative input can still activate the output.
  • Sequence Control: The series connection ensures the system operates in the correct sequence, which is critical for applications that require strict control.
  • Simplicity in Design: By combining an OR valve with a series connection, you can achieve complex functionality with minimal components.

Implementation in AutoSIM 200

To simulate this system in AutoSIM 200, follow these steps:

  1. Open AutoSIM 200 and create a new project.
  2. Add components from the pneumatic library:
    • OR valve (3/2-way valve)
    • Double-acting cylinder
    • Limit switches
    • Push buttons or sensors
  3. Connect the components in series, ensuring the OR valve is correctly wired to the push buttons and sensors.
  4. Run the simulation and test the circuit:
    • Activate one input → Cylinder extends.
    • Activate both inputs → Cylinder still extends.
    • Limit switches in series will control the cylinder’s retraction.

Conclusion

The OR valve and series connection in a pneumatic circuit offer a flexible, reliable, and cost-effective solution for controlling complex pneumatic systems. By combining the OR valve’s alternative flow path with the series connection’s sequential control, you can design circuits that provide efficient operation for a variety of automation tasks.


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