Book Image

PLC and HMI Development with Siemens TIA Portal

By : Liam Bee
Book Image

PLC and HMI Development with Siemens TIA Portal

By: Liam Bee

Overview of this book

With automation requirements on the rise, Siemens’ TIA Portal development environment is almost a necessity for any automation engineer. The Totally Integrated Automation (TIA) environment helps seamlessly integrate all things automation, from PLC hardware and software design to HMI development. This book helps you understand the tools available in the TIA toolbox and shows you how to write code effectively. The book begins by introducing you to the TIA environment, covering the layout and tools available. Once you’ve got to grips with the environment, you’ll find out how to create hardware to write programs against, including adding IO modules and assigning memory for input and output. Next, you'll develop logic in all of the languages that TIA Portal offers, such as Ladder, Function Block Diagram, and Structured Text (SCL) (note that Statement List is not covered as a deprecated language), as well as the newest language, Cause and Effect (CEM). You’ll also discover how to store standard code in libraries, creating a version control system that is easy to manage and aids standard design. Finally, following the PLC design chapters, you’ll learn how to develop HMI applications in TIA Portal’s latest unified hardware. By the end of the book, you'll be well equipped to use all of the features that TIA Portal V17 offers.
Table of Contents (21 chapters)
1
Section 1 – The TIA Portal – Project Environment
5
Section 2 – TIA Portal – Languages, Structures, and Configurations
11
Section 3 – TIA Portal – HMI Development
16
Section 4 – TIA Portal – Deployment and Best Practices

Asynchronous data access considerations

It is important to remember that many modern human-machine interfaces (HMIs)/supervisory control and data acquisition (SCADA) systems will access PLC data asynchronously. This means that instead of waiting till the end of the PLC scan to obtain or write data, the HMI/SCADA system will interrupt the scan to update or obtain data.

Normally, this is not an issue. However, when references via InOut interfaces are in use, it can cause unexpected behavior. This can be very difficult to diagnose because the next time data is updated, it may not be updated in the same place in the scan.

Have a look at the following screenshot:

Figure 8.13 – Example of an erroneous configuration with InOut interfaces

Figure 8.13 is an example of a configuration that is valid by the compiler but introduces issues if data blocks are interfaced with an HMI.

The blue data blocks represent asset data—they are connected to InOut...