Software gives machine controls more value, departs from traditional code

Controls development in automation applications has advanced beyond producing “code” to integrating mechanical, electrical, and control domains of the machine to create a mechatronic entity. A multidisciplinary development approach helps create controls designs that are easy to repeat, maintain, and enhance.

By Daniel Ghizoni December 17, 2011

Machines and controls are becoming more software-driven and, as such, having a structured approach for requirements, specifications, design, development, and post-sales service is imperative to the successful execution of the project, and the successful harboring of a company’s technical know-how. Controls development in automation applications is no longer solely about producing “code,” but instead it encapsulates the mechanical, electrical, and control domains of the machine. These systems are much more deeply integrated today, resulting in what is best considered a “mechatronic entity.” Embracing this understanding opens the door to a multidisciplinary development approach to controls design.

Linear design tradition

The traditional approach to automation system design followed a linear path, where outputs from one step become the inputs of the next. The mechanics of a machine were the first in line and consumed the majority of the project duration. It was followed by the electrical integration of the machine components, and only after this step was the software, or controls, component introduced.

Suffering from scheduling pressures to finish the machine, the main focus at this stage was to get the machine running as quickly as possible. Even if this individual example machine was completed to the customer’s satisfaction, these methods do not often result in designs that are easy to repeat, maintain, and enhance over time.

Smarter, sustainable engineering

To develop more robust mechatronic entities, the design process and the selected tools must promote sustainable, smart engineering.

The design cycle of the mechatronic system follows a more collaborative structure, with constant reviews and iterations throughout the design process. A good place to start development of the software architecture and tasks is right after creating the product idea, and before even beginning the product specification. During this transition, designers can begin exploring the feasibility of ideas and concepts, and start defining key value-adding processes.

Faster innovation

But why is there a need for sustainable engineering? Machine builders, small and large, face a global and ever-more competitive marketplace, posing many challenges:

  • Machine customization needed to win business: customers want more say on how to control or execute processes.
  • Shipping machines worldwide: do you have the ability to quickly adapt and cater to different markets, with different needs?
  • Fast development times: do you have the ability to innovate, while keeping lead times short?
  • Post-sales service: are processes established to handle machine support—across borders?
  • Maturing fleet management: will the machine be able to “grow” and be updated seamlessly?

How can smart, sustainable engineering be achieved? It begins by considering the overall mechatronic entity and forming a multidisciplinary team to develop the machine. Complementing this with open and compatible standards, a modular system architecture, and model-based design and simulation control programmers and system integration can transition to more sustainable engineering design. Here’s how.

Control design changes

Using standard programming languages contributes to the sustainability of the development, and to the protection of the automation investment. Therefore it is important to consider development languages that are based on industry standards, such as specified by IEC 61131-3. Conforming to standards unties the intellectual property—the ideas, the innovative-portion of the design—from the automation provider. In addition, users should expect to have a choice in the programming language or languages to be used—are ANSI C and C++ also available? Support for a plurality of programming languages gives flexibility in implementing solutions using the most effective constructs while considering the needs of existing legacy implementations, the available expertise, and end-user specifications. Naturally, the availability of a variety of standard languages reduces the investment required to learn and adapt to the development tools necessary for a specific vendor’s technology.

A modular system architecture also adds to the sustainability of the design effort, during development and through the service stages of the machine life cycle. The application project for a mechatronic system is no longer a monolithic entity but is segmented or dissected into many subprojects. In the development stage, this breakdown in the project structure allows easier collaboration among the team members. An efficient use of the available engineering resources is achieved, with optimum results in productivity. In the service stage, it allows for easier maintenance and flexibility in adding features and enhancements.

Modularity in the project structure contributes to a sustainable engineering practice also by capitalizing on the reuse of intellectual property across platforms or projects. Technical know-how is easily replicated from project to project, and from machine to machine. Cultivation of company best practices is improved with the ability to manage central, user-defined libraries that can be easily implemented in parallel or future projects, as well as easily exporting and reusing modules from project to project.

Another important enabler is the ability to separate software development from the hardware selection. From a practical standpoint, separating software from hardware allows the developer to begin working on the software modules and structure before finalizing the decision of which PLC, PAC, or IPC (programmable logic controller, programmable automation controller or industrial PC) to use. In addition, this approach allows the same design and software to be implemented on a variety of PLCs. Here the benefit is that the final hardware selection can be made independently of the controls development process to meet unique specifications, performance requirements, or product positioning (value, mid-market, and premium), without the need of extensive tailoring of the programming.

Faithfully simulating the execution of software modules before implementation in the machine is an important addition to the design process, at all stages. Simulation in PLCs, PACs, and IPCs makes incremental testing and verification, the development of new ideas and concepts, and troubleshooting and debugging, quick and simple. While prevalent on a number of high-tech industries for many years, model-based design has of late made advances in the industrial automation field. In model-based design, a physical system is represented as a set of modeling blocks or mathematical equations. This model is then used for simulation of operating conditions, and also for the design of the very control system used to control it. Although typically coupled with a higher up-front cost, the advantages of such strategy are many: rapid prototyping and deployment of the machine, a better understanding of plant behavior, and the ability to simulate operation environments, including potential disturbances. Consider choosing programming tools that allow a link to established modeling tools.

Machine builders, large or small, need to ensure that their design process is structured in a smart and sustainable manner to remain competitive in the global marketplace. Treating the automation system as a mechatronic entity, and applying smart and sustainable design practices enable the automation provider to foster its technological expertise and succeed on ventures time and again.

Next generation programming advantages

Advantages of next-generation programming software, according to B&R Industrial Automation Corp., include:

  • Flexible implementation
  • Preservation of legacy assets
  • Better use of available expertise and end-user specifications
  • Sustainable design during development and service lifecycle stages
  • Optimized productivity
  • Faster modifications and enhancements
  • Reuse of intellectual property across platforms and projects
  • Separation of software from target hardware
  • Fewer errors
  • Faster time to market

– Daniel Ghizoni is senior solutions engineer, B&R Industrial Automation Corp. Edited by Mark T. Hoske, CFE Media, Control 

For more, see the January North American print and digital edition cover story on control programming and related Online Extras.