What kind of controller is best for your application? Is it a PLC (programmable logic controller) — or perhaps you should use a PAC (programmable automation controller), or maybe a PAD (programmable automation device)? When it comes down to it, the name is not that important. What is important is developing a clear understanding of your needs and then finding the controller that best targets them.

In the world of industrial automation, technology has evolved leading to innovations in controllers and I/O, enhanced engineering tools and entirely new system architectures. The controller we are familiar with can now take virtually any size and shape, from a traditional industrial PLC, to a PC-based controller and even a “nano-sized” brick.

On paper, an automation controller must cover a broad range of application requirements. The platform should offer standards-based openness; flexible, single-database integration for the entire system; standard IEC-61131-3 control programming and configuration languages; the ability to create preconfigured libraries of reusable code; and object-oriented design of complete system architectures.

The reality is that very few controllers can truly provide these capabilities in one package. But such solutions do exist, so it’s important to identify unique control applications and then look at what the controller should do to help you solve the application. Following is a list of six control applications: If we look at each of these, and identify some core elements that you must have, we can paint a picture of what the modern automation controller can deliver.