Do strategies for implementing embedded control hardware and software differ from prepackaged controllers, such as a programmable logic controller (PLC), programmable automation controller (PAC), or industrial PC (IPC)? While there has been a heated debate about the differences of PLCs, PACs and PC-based automation solutions, the differentiation of these targeted systems from embedded control solutions always seemed straight-forward.
Embedded hardware, software
Embedded hardware provides an increased level of customization, the integration of custom I/O modules and the possibility to tailor the control system to application specific performance and price expectations. But this flexibility comes at the expense of additional development burden and a significantly different workflow for system design. Electrical design expertise and special tools are needed for the design and validation of embedded hardware.
On the software side, engineering teams need to create board support packages, take care of I/O drivers, and adapt an embedded operating system before they can start developing the automation software. Usually this is an iterative process where the hardware team needs to go through several hardware revisions until all of the requirements are met and the platform is ready for initial deployment. In addition to this extended development process, the user also needs to obtain all of the required certifications and maintain the design over the lifetime of the product. This process is costly, and often machine builders simply don’t have the expertise, time, or budget to employ embedded design teams or hire external consultants, which limits their capability to innovate.
Embedded system design platform
Some companies blur the lines by providing a platform-based approach to embedded system design. An integrated solution combines an open and powerful software development environment, designed to accelerate the productivity of engineers who build embedded control and monitoring systems with high-performance real-time processors and field programmable gate arrays (FPGAs), which customers can program. By adopting a graphical system design platform, engineering teams can begin implementing their automation application, leveraging existing software frameworks and choosing from a variety of programming approaches including graphical development, .m file scripts, and connectivity to existing ANSI C and hardware description language (HDL) code.
The resulting application can be deployed to a variety of embedded hardware platforms, including industrial-grade control systems and board-only systems or a system-on-module (SOM). Leveraging this approach, machine builders can quickly implement an off-the-shelf embedded hardware solution without needing to build custom electronics or port the final code to a cost-optimized deployment target with their own application-specific I/O board.
When should an embedded controller be used?
The decision between an embedded solution and a more traditional automation system like a PAC or PLC should be based on application-specific needs. Embedded controllers offer a greater level of flexibility and are ideal for automation tasks that require high-speed control, advanced signal processing and analytics, or custom protocols and algorithms. They typically perform the application tasks that provide an innovative differentiation.
In larger applications, it’s common to use embedded controllers in conjunction with more traditional systems, either because the system is evolved rather than redesigned or because the system benefits from a modular controls architecture.
A platform-based approach to embedded design makes embedded solutions accessible to design teams that don’t have the time, budget, or expertise for custom design. Combined with a variety of deployment hardware, this approach allows customers to quickly develop powerful embedded solutions and deploy to hardware that meets the application needs for form factor, performance, footprint and price.
– Christian Fritz is principal product manager, embedded systems, for National Instruments; edited by Mark T. Hoske, content manager, CFE Media, Control Engineering, firstname.lastname@example.org.
- Controllers choices, including PLCs, PACs, IPC and embedded controllers, can vary by application.
- An embedded system design platform can help: Design once and deploy to many control platforms.
An FPGA-based embedded controller offers flexibility for future changes and upgrades.
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