Equipment for PLC programming

 

 

 

 

 

What does ‘PLC’ mean?

A PLC (Programmable Logic Controllers)  is an industrial computer used to monitor inputs, and depending upon their state make decisions based on its program or logic, to control (turn on/off) its outputs to automate a machine or a process.

NEMA defines a PROGRAMMABLE LOGIC CONTROLLER as:

“A digitally operating electronic apparatus which uses a programmable memory for the internal storage of instructions by implementing specific functions such as logic sequencing, timing, counting, and arithmetic to control, through digital or analog input/output modules, various types of machines or processes”.

Traditional PLC Applications

*In automated system, PLC controller is usually the central part of a process control system.
*To run more complex processes it is possible to connect more PLC controllers to a central computer.

Disadvantages of PLC control

- Too much work required in connecting wires.
- Difficulty with changes or replacements.
- Difficulty in finding errors; requiring skillful work force.
- When a problem occurs, hold-up time is indefinite, usually long.

Advantages of PLC control

* Rugged and designed to withstand vibrations, temperature, humidity, and noise.
* Have interfacing for inputs and outputs already inside the controller.
* Easily programmed and have an easily understood programming language

 

Programmable Logic Control

What is Programmable Logic Control? This equipment is very common in industrial over the world.It use in many equipment and machinery.It make the processing more easier to handling. In general,PLC  is a collection of electronic device which are in  place to ensure the stability,accuracy and smooth transition of a process or manufacturing activity.The relay,timer,counter,preset counter  

Equipment for PLC programming

 Now in automation industry,the common practice for programming the PLC is using a desktop or laptop.It easy to handle and more comfortable when perform the design or troubleshooting job. PLC manufacture also in advance to produce a user friendly PLC software in market today.It made our programming task more easy and can get the best.....

PLC Programming

Introduction for PLC programming How we can make the PLC functioning properly to control the machine?We need to stored the PROGRAMMABLE CONTROL SYSTEM  into the PLC memory.We need the special PLC PROGRAM to written the PLC language.For that task..we need the PC or LAPTOP to run the programming software :D After we make a sketch

Hardware Components of a PLC System

Processor unit (CPU), Memory, Input/Output, Power supply unit, Programming device, and other devices.

Central Processing Unit (CPU)

CPU – Microprocessor based, may allow arithmetic operations, logic operators, block memory moves, computer interface, local area network, functions, etc.
CPU makes a great number of check-ups of the PLC controller itself so eventual errors would be discovered early.
System Busses
The internal paths along which the digital signals flow within the PLC are called
busses.
The system has four busses:
- The CPU uses the data bus for sending data between the different elements,
- The address bus to send the addresses of locations for accessing stored data,
- The control bus for signals relating to internal control actions,
- The system bus is used for communications between the I/O ports and the I/O unit.

Memory

System (ROM) to give permanent storage for the operating system and the fixed data used by the CPU.
RAM for data. This is where information is stored on the status of input and output devices and the values of timers and counters and other internal devices. EPROM for ROM’s that can be programmed and then the program made permanent.

I/O Sections

Inputs monitor field devices, such as switches and sensors.
Outputs control other devices, such as motors, pumps, solenoid valves, and lights.

Power Supply

Most PLC controllers work either at 24 VDC or 220 VAC. Some PLC controllers have electrical supply as a separate module, while small and medium series already contain the supply module.

Programming Device

The programming device is used to enter the required program into the memory of the processor.
The program is developed in the programming device and then transferred to the  memory unit of the PLC.

 

Category of PLC Applications

• Automatic Gates using PLC
• Control Seven Segment Display with PLC
• Conveyor Control Using PLC
• Elevator with PLC Program
• Heater Controller with PLC
• Lock Unlock Door Using PLC
• Parking Information using PLC
• Password Using PLC
• PLC and Servo
• PLC for 3 Movement
• PLC for Assembly Line
• PLC for Automatic Welding
• PLC for Binding Machine
• PLC for Cutting Machine
• PLC for Filling Machine
• PLC for Injection Molding
• PLC for Marking
• PLC for Packing
• PLC for Rotary Bottle Washing
• PLC for Sorter Machine
• PLC for Water Treatment
• Push ON Push OFF with PLC
• Standard Sequence Programming for PLC
• Timer Countdown with PLC
• Traffic Light with PLC
• Automated washing  machines

PLC Ladder Logic

• Is it normally open or normally closed?
• A basic rung of logic
• Instruction types
• MCR, JSR and basic structure of a PLC program
• Adjusting Timers and Counters
• What is integers, binary, floating point data memory areas.
• symbols and rung descriptions

Standard Operating Practices (SOP)

• Backing up your PLC programs
• Protecting your PLC programs
• Reliable operating procedures
• EPROM for zero downtime
• Documenting change
• Safety while troubleshooting
• File Management
• Downloading and Uploading

Troubleshoot Actual Problems

• Basic troubleshooting theory
• The most common problems
• Relating your PLC program to the real world
• Tracing and monitoring input and outputs
• How to recover quickly from lightning and other power problems
• Actual troubleshooting exercise
• Using RsLogix's ^™ Advanced Diagnostics

Setup PLC Hardware and New Program

• Configure PLC Drivers
• Setup PLC IO
• Set up PLC Communication
• Create a New PLC Program
• How to Structure a PLC Program
• Document PLC Program
• PLC Programming Tips
• Writing Diagnostic and Troubleshooting rungs

Example 1:

Write a program (instruction list) to put the number (4000) in a memory location, and the number (41)in another location. divide the first one by the second and put the result in a memory location.

solution:

  

Example 2:

Make a program to increase the counter by one with each pulse from the pulse generator SM0.4 (on rising edge) , and decrease another counter by the same pulse.

Solution:

 steps of solution would be like this:
 1. put zero in memory location vw100.
 2. put (10) in the memory location vw110.
 3. with each rising edge from SM0.4 (every 30 sec), we increase memory location vw100 by one. and at the same time decrease  vw110  by one. the program will continue like that without any instruction to stop.
#please note that:
 MOVW => move word
 INCW => increment word
 DECW => decrement word