Introduction to programming a SIEMENS LOGO PLC

Introduction to programming a SIEMENS LOGO PLC

  Author: Seyedreza Fattahzadeh 
  Product Group eBook 
  Format: PDF file
  Number of pages:205


This E book provides you with fundamental and cutting-edge coverage of both hardware and a software aspect of a great little PLC which is called "LOGO" that of course is made by Siemens.

Hardware aspect of a LOGO! PLC

Implement your own simple automation projects or simplify your existing control cabinet which already contains time switches, timing relays, counters and contactor relays - LOGO! is the complete all-in-one solution. With its 8 basic logic and 31 special functions, LOGO! replaces a wide range of conventional switchgear/control devices. A LOGO! performs small-scale automation tasks more quickly and free up space in your switch cabinet. LOGO! PLC Controller has 8 DC inputs, 4 relay outputs HMI Display (depending on the particular model number) and Keypad, Analog inputs 0-10vdc. With real Time Clock. You can expand LOGO! switching power by using I/O expansion module specially designed by Siemens (up to 24 DI and 12 DO). Now even more versatile for analog value applications and simple control tasks. Easy-to-mount, minimum wiring, easy programming . . . done!


 LogoSoft Comfort programming language


 LOGO! Soft Comfort – stands for sensationally easy and quick configuration. This allows the creation of ladder and function block diagrams by selecting the respective functions and their connection via drag & drop. In addition, the entire switching program can be simulated and tested offline on the PC. Also possible: an online test in both program displays during operation. LOGO! Soft Comfort provides professional documentation with all of the necessary project information such as switching programs, comments, and parameter settings. Program Memory 300 Lines or up to 512 Function Blocks. Input switches operable from the computer keyboard or by clicking on them. Timed Timer and counter contacts Analog functions, Compare, Gain, Ramp, Mux, 365 Day Clock Day, Month, Years Weekly timer. Latch and Unlatch Relays PWM, Modbus - Read - Write Special timers and multifunction On-Delay Timers (TON) Off-Delay Timers (TOF) Retentive Timers (RTO) U/Down Counters, Hour counter Timer/Counter Reset (RES) Shift Register, and pulse relays Set Reset Logical Outputs (AND, OR, NOT, NAND, NOR and XOR) Boolean functions Graphic or Text Display and more. This book represents the best way to learn or get trained on Ladder Logic or Function Block programming since it is  like you were buying three different books: One for Theory, one for Lessons and a third one for Real applications:.


In chapter 1, I explain difference between a contactor and a relay, power and control circuits, application START and STOP push buttons, design of a seal-in circuit, a bimetallic overload relay, application of few mostly used rely diagrams related to industrial control circuits such as reversing the rotation of a 3-phase motor, STAR and DELTA motor configurations. Chapter 2, Sensors and their application, inductive proximity sensors, analog sensors, inductive speed monitor sensors, capacitive sensors, magnetic sensors, liquid level sensors, reflective opto sensors, shaft encoders and their applications etc. chapter 3, history of PLCs, application and different ranges of  PLCs. Chapter 4, full explanation of LOGO! hardware, its different model number and their related hardware and I/O configurations, expansion modules, memory, communication cable, power supply, connecting sensors to LOGO, PT100 RTD sensors, LOGO! TD display. Chapter 5, introduction to complete application of LogoSoft , definition and developing both FBD and LDA PLC programs etc.




Actually lessons on application of LOGO! function blocks starts from chapter 5 in which through so many few lines of codes, I explain how that particular function block is supposed to be used including its related timing table, truth table etc. Step by step showing how to design and implement a PLC circuit program and how to simulate it offline or download into LOGO and actually run it. About 20 pages of text is devoted to "How to start developing a PLC control or circuit program" in which I explain how based on a given specification problem, a novice reader should think logically to come up with a algorithm to generate a PLC program for the process system in hand. In chapter 5, I have defined and designed 3 exercises to master developing the skill of thinking logically when generating PLC programs.


Exercise 1 is related to application of 3 inputs, 2 outputs and few other RS flip flop or AND logic gates to develop a simple state machine circuit.

Exercise 2 is to develop a PLC circuit program for a 4-floor elevator project. This is a very great project in which one should just by using many simple logic gates to come up with a PLC program which controls a 4-floor elevator which is consisted of 4 floor service call pushbuttons, 5 limit switches to detect and control exact location of car and a one digit LED seven segment to display the current floor number. And a simple CW and CCW motor control circuitry to move the car up/down anytime a service calls comes in

Exercise 3 is to develop a PLC circuit program for a vending coin acceptor system. Through this exercise, I explain how a programmer is supposed to think logically to come up with a PLC program solution to control a typical vending machine.


 Real applications


As for real applications, I have included 3 project specifications with complete worked out solutions to amplify logical thinking ability of a novice PLC programmer

1-   Writing a circuit program to control a 3-phase motor to run clockwise and counterclockwise. 2-  Writing a circuit program to turn two motors on with priority. 3-   Staring a squirrel cage 3-phase motor with initialization resistors.


Chapter 6: familiarizing ourselves with LOGO!Soft instructions. Definition of Function Block and Ladder Diagrams, Shift register bits, output block, LOGO TD function key, flags defined on different LOGO devices, message text instructions, analog I/O, basic logo functions, the AND, NAND, OR, NOT, XOR, major programming example with Analyzed solution, latching relay function, most of these functions definitions come with sample exercise programs, related ladder and typical wiring connection diagrams to a LOGO PLC. On Delay Timer, retentive On-delay, Off-delay timer, wiping relay, stairway lighting switch, multiple function switch, weekly timer function, yearly timer, up/down counter, threshold trigger, analog comparator, analog amplifier, analog watchdog, analog differential trigger, analog MUX, ramp control function bock, PI controller, pulse width modulation (PWM), mathematic instruction and error detection,  shift register, softkey instruction, message text, and 10 end chapter programming projects with solutions


1- Control of speed/direction of a 3-phase motor. 2- Changing the STAR to DELTA configuration of a 3-phase motor. 3- STAR/DELTA and CW/CCW control of a 3-phase motor. 4- Design of a residential anti-theft alarm system with a LOGO! PLC. 5- Industrial sequential control of two conveyors with a PLC 6- Industrial sequential control of three conveyors with a PLC 7- Control of solvent level in two containers 8- Control of a master conveyor with different sensors 9- Control of a storage capacity measurement with a PLC 10 Control of a chemical manufacturing process with a PLC.

 Chapter 7: 24 complementary programming projects with solutions


1- A 4-way intersection Traffic Light controller 2- A 3-way intersection Traffic Light controller 3- Designing a Traffic Controller for a main road with two side roads 4- An iron pipe cutting system 5- A car painting system 6- A hydroponics system 7- A four floor elevator system 8- A hot drinks dispenser machine 9- A bottling plant 10- A vending coin acceptor 11- Completing previous project 12-a liquid agitation system 13- a two floor elevator system 14- Design of a water pumping system 15- controlling a parking lot system using a PLC 6- A garden watering system 17- An automated bottling system 18- A pedestrian crossing system 19- A conveyor drilling system 20- A liquid processing system 21- A heat treatment system 22- Canal locks 23- Redoing Example 6-45 with PID algorithm 24- Redoing Example 6-46 with PID algorithm