UNIVERSITY OF KHARTOUM
FACULTY OF ENGINEERING
DEPARTMENT OF ELECTRICAL AND ELECTRONIC ENGINEERING
AUTOMATION LABORATORY 5TH GRADE CONTROL
EXPERIMENT NO (2)
HMI USING WINCC
1. OBJECTIVES:
The main Objective of this experiment is to use WinCC HMI to Monitor and control an ongoing
process in a PLC. The process being a simplified parking system.
2. INTRODUCTION:
WinCC (Windows Control Centre) is a powerful HMI system for use under Microsoft Windows
XP, Windows Vista and Microsoft Windows Server 2003. HMI stands for "Human Machine
Interface", i.e. the interface between the person and the machine. WinCC allows the operation
and observance of the processes that run in a machine. The communication between WinCC and
the machine takes place via an automation system.
An HMI system assumes the following tasks:
Process visualization. Process values and alarms logging.
Operator control of the process. Archiving process values and alarms.
Process and machine parameter management.
3. METHODOLOGY
3.1. THE WINCC PROJECT:
Different types of projects can be created using WinCC flexible. The type of project is dependent
on the system configuration, the size of the system or machine, the required representation of
the system or machine and the HMI devices used for operating and monitoring.
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The default layout of a newly created project looks like shown in the figure below, where:
• Projects are edited in the Work Area. All WinCC flexible elements are arranged on the
borders of the work area. With the exception of the work area, you can organize,
configure and, for example, move or hide any of the elements to suit your individual
requirements.
• All component parts and all available editors of a project appear in a tree structure and
can be opened from there in the Project View. Furthermore, in the Project View you
have access to the project properties as well as the device settings of the HMI device.
• The Property View is used to edit object properties, e.g. the color of screen objects.
• The Toolbox contains a selection of objects that you can add to your screens, e.g. image
objects or operator control elements. In addition, the toolbox also provides libraries
containing object templates and collections of faceplates.
3.2. PROJECT COMPONENTS:
When creating an HMI for some process, the most important parts to consider no matter how
small and simple your HMI is, are:
Connections. Tags. Screens.
There are other components or features that can add to system performance and can be very
essential in big industrial and automated systems such as:
Archiving (Data base Systems). Alarm systems. Logging.
In this experiment, we will go through the configuration of connections, tags and screens since
no HMI can work without these three.
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3.3. WORKING WITH CONNECTIONS:
By connections, we mean the way in which WinCC can access the data present in the PLC to read
or write. WinCC offers many choices for communications which can be divided into two
categories:
Direct Connections:
This is achieved via communication drivers embedded in WinCC software, WinCC has many
drivers from different vendors that enables it to access the PLC unit directly to perform read
or write Operations (The same way MicroWin communicates with S7 200 PLCs).
Connection via OPC:
In this mode, The HMI accesses the data of the process using OPC technology. WinCC can be
an OPC server which provides data to other HMIs running on different PCs, or an OPC client
which requests the data from another OPC server installed in the same or different PC. This
mode can be very helpful especially when the driver for your PLC is no present in WinCC.
In this lab session we are going to communicate via OPC using PCaccess as our OPC server and
WinCC as the client.
3.4. WORKING WITH TAGS:
Tags are the variables or data that represent the process parameters, Input or outputs that are
required to be monitored or altered by the HMI. There are two types of tags:
Internal tags:
These tags are not present in the PLC memory or external process, but are rather in the
WinCC memory area. These tags are used in order to perform mathematical operation on
the process variables or to scale some variable to fit a plot or any other edition on the
variable prior to display. They don’t have any connections associated with them.
External Tags:
These are the real variables or process components that are present in the PLC. For every
tag you define, you need to specify the type of connection WinCC will use to reach this tag,
the address of the tag, the acquisition cycle for the tag and the other features found in the
tag area.
Note: When tags are accessed using OPC server, they have to be defined in the server first
for WinCC to be able “see” them. The address will be given by the server.
3.5. WORKING WITH SCREENS:
A screen may consist of static or dynamic elements.
Static elements such as text or graphic objects do not change their status in runtime.
Dynamic elements change their status based on the process. Visual current process values as
follows:
From the memory of the PLC
From the memory of the HMI device in the form of alphanumeric displays, trends and
bars.
Each screen element is associated with a tag; for example a light can turn on when a tag (Q0.0)
is high.
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4. PROCEDURE:
1. Use Microwin to write and download the ladder diagram of the parking system to your PLC.
2. Use PCaccess to define variables that should be monitored and written
3. Use the test client to check communication and addresses. Save the Pca file and close.
4. Open WinCC, the project wizard will help you set the option you prefer for you HMI
appearance.
5. In the connection area of WinCC, select OPC as your driver. All the OPC servers installed in
the PC will be listed. Select S7-200 OPC server “PCaccess”.
6. Now, in the tag area of WinCC, you can import the tags you defined earlier in Pcaccess.
7. In the screen area, you can use windows styles such as “drag and drop” and “multiple select”
to choose the appropriate graphics from library and place them in the screen area. From the
property area under the screen, you can select the tag associated with every screen element.
5. THE CODE
The code provided is for the operation of a local garage with a total capacity of 5 cars. It has
proximity sensors (I0.0 & I0.1) to control the operation of the entrance gate (Q0.0) that closes
after the 5th car, and the exit gate (Q0.1) that opens each time a car exits.
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