Why plc is used instead of microcontroller

Companies making microcontrollers may not share this sense of history. If you need to replace a controller for a project from five years ago, finding the exact parts you need could prove to be a challenge. Most PLC suppliers have excellent support capabilities, with some, like AutomationDirect, offering free tech support.

However, open-source microcontroller end users often develop their own technical support groups, with answers to your questions often found in discussion groups and forums with needs similar to your own. Or not. When a plant must run and products must be manufactured, reliability and safety matter more than anything else. To read more articles about programmable control, click here.

Since this article was first published, AutomationDirect has done extensive research into the viability of single-board controllers for industrial applications. As a result, AutomationDirect now offers their own brand of industrialized open-source controller, the ProductivityOpen , that mimics the Arduino MKRZero controller but is built to handle harsh environments.

For most, PLCs are the easier option since they are designed with many readily-available functions geared toward industrial applications. Microcontrollers are usually also programmed via application software running on a PC and they are usually connected to that PC via an additional piece of hardware usually called a programmers.

The operation of programs on the PLC is however very similar to that of the microcontroller. The PLC uses a dedicated controller as a result they only process one program over and over again.

An operating cycle through the program running on PLC is shown below. PLCs are the primary control elements used in industrial control systems. They find application in the control of industrial machines, conveyors, robots and other production line machineries. They are also used in SCADA based systems and in systems that require a high level of reliability and ability to withstand extreme conditions.

They are used in industries including;. Continuous bottle filling system 2. Batch mixing system 3. Traffic control. Microcontrollers on the other hand find application in everyday electronic devices. They are the major building blocks of several consumer electronics and smart devices. The advent of easy to use microcontroller boards have increased the scope within which microcontrollers are being used, they are now being adapted for certain applications for which microcontrollers were considered inappropriate from mini DIY computers to several complex control systems.

This has led to questions around why microcontrollers are not used in place of PLCs , the main argument being the cost of PLCs compared to that of microcontrollers. It is important that a lot needs to be done to the regular microcontrollers before it can be used in industrial applications. While the answer can be found from the points already mentioned within this article, it is sufficient to highlight two key points. Microcontrollers are not designed with the ruggedness and ability to withstand extreme conditions like PLCs.

Microcontrollers and PLCs can perform many of the same functions, such as mathematical operations, logic and data processing, and controlling devices. However, microcontrollers are significantly less expensive to obtain. The best way to understand why PLCs are still the clear choice for industrial applications is to examine the key characteristics that make these two types of computers different beyond just their lopsided price tags.

A microcontroller is a compact integrated circuit device that is typically embedded within another device, such as a home appliance, television, or a car, to control a singular function. For example, a car will have one microcontroller for operating the speedometer, another for the auto-braking system, and yet another for the powered windows.

Microcontrollers excel in applications requiring limited computing functions; however, they can perform a wide range of operations, including mathematical calculations, processing logic and data, controlling devices, and handling serial and wireless communications.

In addition, microcontrollers are typically compact in size and inexpensive, with some models being obtainable for less than a hundred dollars. With pure microcontroller programming it can get complicated to figure out exactly how a change in a function is going to affect the whole functioning of the program.

Ladder logic is easy to understand and program for machine control. We have electricians programming them without any involvement from engineering. They can easily troubleshoot the line's electrical systems by themselves and make the appropriate repairs. They can also write their own programs and do modifications to existing ones.

The debugging environment is way and I mean WAY better than what you can normally accomplish with embedded micros. With safety systems it becomes even more important to use safety PLCs and their redundant capabilities and watchdogs to ensure proper functionality.