Model-Based Automation Software

The trend to model-based software development is making an impact in the field of industrial automation. Using B&R Automation Studio Target for Simulink^®, development models constructed in the simulation environment provided by The MathWorks can be implemented on a B&R industrial controller at the push of a button.

"The key innovation is the ability to interface the code automatically generated from Simulink tools directly into the B&R Automation Suite's development environment," says Robert Muehlfellner, automation director for B&R Industrial Automation.

He says that models developed in Simulink, plus the code automatically generated out of the models, can be seamlessly executed on the B&R controls in real time. This capability is built on Real-Time Workshop, one of the components of MatLab Simulink, which generates C code. 

"It allows us to use our ability to have our controls to be programmed in C, which is uncommon in the controls world with PLCs or PACs," says Muehlfellner. "From Simulink, a real-time task is created that can be executed within our controls. In the Simulink toolbox, the user defines input and output variables which can be tagged to I/O points or used by visualization tools. Users see the model executed on the control as a black box."

Once models are built and mapped into the automation architecture, inputs, outputs and other control parameters represented as tags sense changes within the model. Other functions in the model are compiled into a C program which can be executed in real time on the B&R controls, and is integrated with other control tasks using the input and output tags.

Users of Simulink's Real-Time Workshop are typically working on a much lower level, and can leverage the product's automatic code generation algorithms. But the idea is to combine the best of both worlds - classical PLC-type programming and seamless integration of the C modules generated by Simulink.

The target for this solution is more complex processes in areas such as the automotive and semiconductor industries that benefit from advanced model-based design. Engineering is done typically by process engineers comfortable with programming in Simulink, and the C code encapsulated for use within the B&R controls programming environment cannot be easily modified. Interfacing is achieved using the input and output tags, and can be accomplished using either ladder logic or structured text programming.

Advanced simulation is particularly useful for applications where users need to create sophisticated process control models or rapid prototyping. If a process requires special cascaded control loops or real-time, process engineering gauges, engineers often turn to advanced simulation tools to draft their control algorithms. But it can be difficult when they need to convey that information to a controls engineer who implements a solution in PLC code, tests the code on a real machine, gathers results and makes adjustments to the code using an iterative process. 

"The problem of conveying what needs to be done, from the science to the controls engineering, is no longer an issue," says Muehlfellner. "The core process can be drafted using the tool kits available in Simulink. The simulation tool can be used to automatically generate the control code which the user can execute in real time on the controller, view results and test the system instantaneously."