Basics of PLC programming

PLC is a device. Which controls the output device based on the input device and user-developed program. By this PLC over relay logic is,

• Cost-effective
• easy maintenance
• Eas programming
• User friendly
• Easy troubleshooting

The basic common processor for PLC programming using Ladder Programming logic. The steps are,

Analyzing and get the idea of control application

The 1^st and the major step of a program is to get the idea of an application. which you are going to develop. You can use the DC motor when the push button is pressed. This status is displayed by the LED light when the monitor gets turn on. The motor attached to the sensor, that detects obstacles, so when this is turned on, the motor should be turned off. If the motor is switched off, the buzzer should be turned on.

Conditions List and get the design using flowchart

Here, we can design the variables as a flow chart. The variables including are, motor, input switch, output switch, LED, and Buzzer.

 Configuring the PLC programming software

First, you have to open the software, which is on your PC. Select the hardware model in the software. And configure with appropriate input and output modules. Then select ladder language from the list of the languages. Then choose the hardware processor and give a name for the program.

Add the rungs and address them

Based on control application logic, add the required rungs and then give an address to the inputs and outputs.

Error checking

Select the online option from the menu bar, then check the error and make necessary changes after selecting offline. And then goto online and select the run option to simulate it.

Download the program to CPU memory

After the simulation of the program, download the program by selecting the download option through a communication cable or a network. These steps are the basic steps including the PLC programming. PLC Executes the two different programs

1.The Operating system

The operating system organizes the functions, operations, and sequences of the CPU. These are not associated with a control task. The tasks of the OS are,

• Establishing communication with programmable devices
• Handling a hot restart and warm restart
• Updating
• Managing the memory areas
• Detecting and calling the interrupts

2.The User program

It is a combination of various functions. These are required to process an automated task.

• Executing interrupts and handling errors
• Reading and evaluating all input signals
• For specified task, all the conditions are initiating

In the present industrial automation sector, several leading plc manufacturers develop PLCs. These are from small to high-end PLCs. Each PLC manufacturer has its own software to configure the PLC hardware.

Some of the programming languages of PLC are,

1.Textual language

• Instructions list
• Structured Text

2.Graphical Language

• Function block diagram
• Ladder diagrams
• Sequential function chart

The function blocks are available in each PLC software. The function blocks includes the  timers,counters,strings,comparators,arithmetic,numeric functions, etc.

PLC programming devices

The different types of programming devices are used to enter, modify and troubleshoot a PLC program. These include PC and handheld-based devices. In this device, a proprietary device is connected to PLC through a cable. These devices are compact and easy. But the handheld devices have limited capabilities.

A personal computer is used for programming the plc in conjunction with the software given by the manufacturer. By using this, we can run the program in online or offline mode. And we can also edit, monitor, and troubleshoot the program of the PLC. The PC consists of program code. It is corresponding to a control application that is transferred to the PLC CPU via the programming cable.

Ladder Logic PLC Programming

Ladder logic is the most basic and simplest form of the PLC program. It has 2 push-button switches. If any one of the switches closed, the lamp glows. Here, the horizontal lines are called, rungs, vertical lines called rails.

PLC training institutes in Hyderabad

• Ladder logics
• MKR industrial automation
• Academy of automation
• Nano scientific research center
• Electromatic technologies
• Twg international
• Prolific Systems & Technologies
• Maa Bhagwati institute
• Smec labs
• Enrun India Mep Automation
• Air voice engineering solutions
• NIIT Ltd
• Pertecnica engineering LLP
• Jeev Automations