Author: Seyedreza Fattahzadeh
Product Group : eBook
Format: PDF file
--:Number of pages
To help individuals who want to gain enough experience at school while taking few regular introductory courses in the PLC field, I have designed and implemented a relatively complex project which its title is:
Programming an automated parking system with
SIMATIC STEP 7 and S7-300 PLC
My four principal concerns to design and implement this project were:
1- Choosing the project: I chose the following industry recognized project:
Programming an Automated Parking System with SIMATIC STEP 7 software and S7-300 PLC
2- System Specification:
The PLC based system will keep track of 16 cars in the parking area. It will not allow more than 16 cars to park. It will show the number of lots unoccupied, will automatically raise the Gate arm to allow cars into the parking lot or leaving it. It keeps track of amount of time a car is parked, the time driver is leaving the parking lot, shows current and exit Time and Date and display them on an HMI or a PC's display or monitor (WinCC explorer based application program). PLC will finally calculate cost of parking for each car parked in the Parking. When amount is paid, the parking operator depresses a paid button, the exit arm gate is raised, and one unit is added to the total number of vacant cars in the Parking lot. All data related to cost of parking is shown in tabulated fashion on either the HMI or PC's monitor being used and are connected to the main PLC controller.
3- Documenting the project:
The content of text generated as documentation of the project consisted of 116 pages in which all codes related to the following control programs are explained fully.
Three important pieces of control programs are developed to get the hardware perform according to the system specification:
A) - The main PLC control program which activates all I/Os (toggle switches, IR sensors etc) and output signals and communicates with HMI device or PC's monitor. The main program is consisted of tens of Networks that each Network is consisted of at least 10 or more PLC instructions.
B) - specially designed HMI program which allows the parking operator to view and control all activities going on the parking area. Most of this program is related to the design and setting of different parameters to create images of counters, switches pushbuttons etc. The operator can view the status of each parking space, or the amount of parking cost the while a driver owes the parking management.
C) - A specially designed SIMATIC WinCC based program which allows the operator to view and control all activities going on the parking area on his PC's monitor. The application program developed for this application deals with how different parameters related to parking information is supposed to be set and code to be developed to get all information to be shown on typical PC's monitor. It is mostly performing the same function as the HMI device which its function was explained earlier.
D) - Schematics diagrams of all hardware related to a 2-digit numeric LED display (to show current number of cars in the garage), PCB schematic diagram of a small area regarding the parking area with 16 toggle switches and 32 LEDs, a break-beam sensor circuit and two arm gate DC motors are given and explain fully in the text.
4- The goal of the project:
In the text, the complete implementation of project by means of 3 application control programs are presented to you. Study them thoughtfully and your task is to re-write your own version of the same PLC application programs. Use your PLC simulator or your own PLC hardware (any brand!) to develop a similar program. When you have done it, simulate your solution to see if you can get it working at the first try. If you did not succeed at the first try, then compare your solution with mine presented in the text. When you find out what is wrong in your control program, go ahead and fix it. When you finally succeed make it, this means you are on the right track towards mastering your PLC programming knowledge. And that is the purpose of this manual.
The prototype version of the project is designed and implemented in my office lab. All of the control programs are presented to you after I have made sure that they are functioning 100% according to the system specification.
To watch the performance of the project hardware and software in action, click on the link: http://youtu.be/51oqLRxXcHk
The schematic diagrams of all hardware circuits used in this project are provided. If you wish, you can even design and implement your own hardware system similar to mine or even tailor it to the one with more features you wish to have. Or, you can still learn by simulating your own program and checking out its performance against mine. And if you find yourself stuck up at any step, you can check out my solution against yours!
What is the main reason for you to purchase this project e-book?
frankly, by writing small programs to learn how to use the PLC instructions is for the time you are taking an introductory course in a collage to learn how to start programming a PLC to do the exercises , BUTwhen you are applying for a job as a PLC programmer, the employer will NOT ASK you to write a simple PLC program just to "START", and "STOP" a 3-phase electro motor, on the contrary , he will give you a Project scope and will expect you to read it, understand it, and if you do not have any good question to ask, TO DO IT.
I have come up with a solution for those who an intermediate level of knowledge on programming any type a PLC but need to learn how to take a relatively complex projectspecificationand turn it into a working PLC control program.
The text assumes you have an intermediate level of background with programming any brand of a PLC- perhaps you are a mechanical or Process Engineer and you need to learn how to program a typical PLC to do some serious control programming similar to the ones usually employers will ask electrical techs or Engineers to do in a PLC based automated field.
Program has to control total of 16 toggle switches (to show if any spot is vacant or occupied), 32 LEDs, 2 green and red LEDs to inform in coming drivers if there is any vacant spot in the parking or not, a break-beam sensor (IR), two arm gate DC motors, 4 arm gate feedback limit switches, one 2-digit LED numerical display to show the number of vacant spots, communicate with an HMI display device, or communicate with PC's monitor to show all the activities going on in the garage in harmony! I assume he who can come up with a ladder logic control program as a solution for this project, he defiantly can do any other project which is even much more complex than this EASILY! Generating a ladder logic program for this project require you to know what you are doing other wise, it would not work right!. You have to make use of basic function blocks such as, flags, latches, timers, counters, Function Blocks, setting all Data Tables and Tags, designing HMI screens and developing an application program based on the state of art software such as SIMATIC WinCC Explore (SIMATIC WinCC is a supervisory control and data acquisition (SCADA) and human-machine interface (HMI) system from Siemens) etc.
In PLC programming business, you have to have a complete self confidence on yourself that "you can do it" when applying for a job.
You can only emit that self confidence when you believe in yourself truly, BUT how can you achieve that self confidence? By defending your programming knowledge not just by talking, BUT by proving it. You must show your future employer that you can handle the job of writing at least a fairly complex program in few hours. That knowledge can not be achieved unless you had done a few successful projects already. You can purchase my e-Book and just use a typical simulator software and write your own program, simulate it and then compare it with my solution and LEARN! Your learning process will start as soon as you even start reading the problem specification. And then in your resume, you can add the sentence: " I am looking for an entry level job in programming PLCs and the most complex program I did, was to write a Ladder Logic program to control an Automated Parking System using STEP7 software and S7-300 PLC plus two monitoring equipments such as a typical HMI and a WinCC based PC display devices" which was working according to its predefined hardware specification.". And watch your future employer's face and reaction when he is reading your RESUME! Probably he will be interested in what you did and will ask you to explain more about it!
Topics covered in the text are:
Chapter 1- Project specification of the system, Application of a touch screen display (TSD) HMI device, Circuit explanation and Break-Beam sensor, Arm gate motor, related limit switches and motor driver PCB, Display counter, Sixteen toggle switches to indicate presence of cars parked, Paid pushbutton switch, HMI display device, Application of SIMATIC WinCC software,
Chapter 2 – Explanation of the PLC ladder logic control program, Main program flowchart of the project, Declaration of the main DB and its components, Developing programs for phases 1and 2- moving the arm gate up, Developing programs for phase 3- A car enters the parking space # 5, Developing programs for phase 4- Calculating the cost of parking, Developing programs for phase 5- The car is exiting the parking space, Developing programs for phase 6- The paid button is depressed, Application of S7-PLCSIM to simulate the developed software,
Chapter 3 – Adding an HMI display to our project , Installation of a PanelMaster LCD screen touch panel, Developing HMI display control software with PM Designer,
Chapter 4 - Application of WinCC software as an HMI task, Phase 1- Developing an HMI application with SIMATIC WinCC, Phase 2- Developing a new SIMATIC S7 type driver, Phase 3 - Creating a WinCC project , Phase 4- Creating the settings related to the main screen page,