Custom Sheet Metal Fabrication: What You Should Know

Posted on: 11 March 2015

Programmable logic controllers date back to the late 1960s. Now, they are used to automate systems of all kinds, from traffic lights to theme park rides. In fact, you probably interact with things that depend on Eaton PLCs every day without even realizing it. They play a vital role in technology management and automation, keeping key components of society operating on a predetermined schedule. There are two primary types of PLCs. Here's a look at what you need to know about each of them.

The Types of PLC's

Programmable logic controllers are available in two primary forms – modular and fixed. Both of them provide the same key functions and consist of a central processor and a user interface. The controllers can be programmed to handle a variety of configurations and respond with a series of control functions based on the programming. You can adjust the input requirements and output processing as necessary using the user interface. All of the system's core activities are regulated by the processor and your programming.

Fixed PLCs

Fixed PLCs are designed to serve basic functions, but they are not typically equipped to handle more complex processes. Fixed units are smaller in size, which makes them convenient when you need something compact. The whole structure, including the power supply and the processing unit, are all contained within a single housing.

For a fixed PLC to work correctly, the entire system must be in good condition. A single malfunction of any component will leave you facing replacement of the entire unit. Since everything is encased in the single unit, there's little warning when a component is failing. If you're opting for a fixed PLC system, you'll want to reduce your risk of downtime from equipment failure by keeping a replacement unit on hand at all times.

Additionally, fixed PLCs are equipped with a fixed amount of memory, so when you choose these controllers, you'll need to consider how much on-board memory you'll need. Since everything is housed in a single structure with these units and they have limited processing capability, you can't upgrade the memory. You also can't expand the system without having to replace the entire unit. If your business operations start to grow beyond the capacity of your current controllers, you'll have to replace your PLC systems to accommodate those changes.

Modular PLCs

Modular PLCs are larger than their fixed counterparts, so they don't work well in compact operations. They are often referred to as rack-mounted controllers, and they consist of a base that allows for the use of several independent components, including multiple input and output components.

Modular PLCs are a bit more versatile in terms of memory capacity. These systems have the capacity to store more information, because you can expand the memory more easily. The modular PLC structure was designed specifically to allow for expansion and growth in most any system. If your operations are growing or you expect them to grow over the next few years, modular PLCs are the way to go.

In a dynamic business environment, a modular PLC system may be ideal, because the core flexibility of these systems will allow you to mix and match your components. The input and output sections are plug-and-play in these structures, so you can customize the operation as needed, responding almost immediately to changes in your operational requirements.

When it comes to system malfunctions, the fact that the components are all independent in a modular PLC system makes it easier to troubleshoot. And, you can replace a single component quickly to restore the processes immediately while you're trying to determine the source of the problem.

Before you make the decision to invest in either modular or fixed programmable logic controllers for your business, consider the information here to determine which will be the best fit. That way, you can make a single investment with the confidence that you're getting what's right for your operation.