The Heart Of an Industry can also be called A “PLC” or ” Programmable Logic Controller “.
A PROGRAMMABLE LOGIC CONTROLLER (PLC) is an industrial computer control system that continuously monitors the state of input devices and makes decisions based upon a custom program to control the state of output devices.
Ever since the semiconductors were invented, the electronics industry grew exponentially at an exceedingly high rate in terms of the number of electronic devices produced each year.
Microprocessors, which are made of millions of semiconductors, are now more powerful than ever before. From 8-bit processing, microprocessors now support up to 64-bit processing and are THE standard ones to use these days.
Operations a PLC can perform :
- Mathematical operations
- Serial communications
- Wireless communications
- -Pr· -Logical processing
- e-processing of data for Machine Learning
- Controlling devices for a DIY Smart Home
- Reading data from both Analog and Digital devices
You see, the basic PLC was actually designed to be future-proof and is still being developed by different makers. They even have different types of PLCs that suit the control system to their size. Having said that, here are some of the reasons why the PLC is used over the microcontrollers.
Why PLC used
- User-friendly
Anyone can easily learn PLC and immediately start using it because it has a very small learning curve, a programming language used for PLC generally is “Ladder Logic Diagram” which is convenient and short to execute compared to programming an Arduino Uno board. When we buy any PLC it comes with a user manual that has detailed instructions so that the consumer can use the PLC’s full potential immediately. - Ease of programming
“Ladder Logic Diagram “is a graphical or pictorial type of programming language in which we just have to ” connect the two vertical lines to create a network, and the single line is called a ‘Rung’, which is ‘ON’.
In the case of other microcontrollers, Flowcharts, Tables, piecharts, etc can be created, but they are programmed in a lower-level language like ” C “, compared to the Ladder diagram, functions are already given and we have to place the elements in a process to create a network. Also, we don’t have to remember all the code unlike in C programming. - Modular Design
The modular PLC have different modules that you can just “Plug n Play ” in order to start using them. Expanding your system will only take a very short amount of installation time because the modules are just basically plugged into the rack mount of the PLC. Modules can also include Memory, I/O points, and Communications.
This design allows PLC to be scalable and hence allows your control system to expand along with the business. When a fault happens in a PLC control system using a Modular PLC, you can easily identify which module caused the problem, replace it with a spare one, and start the operations again. The faulty module will be sent to the service center for repair. It’s that easy. - Safety systems
Diagnostic features are installed in all PLC devices such that before the system even starts, it detects errors that the operator or programmer may have overlooked in his PLC Commissioning.
Also, the rudundancy PLC system which offers multiple safety options like
– Continuing the Industrial Process in case of breakdown or system fault or power fault, where 2 exact similar systems are installed in case of emergencies like these
– To avoid any production loss to the industry
– Every operation and execution can be monitored and supervised and recorded for report making
– Programs can be made password protected for proprietary purposes of the individual industry - Robustness
PLC is an Industrial grade device, whose controllers are designed inside a rugged shield case that protects the controllers from dust, high temperatures, power fluctuations, electromagnetic induction, electrostatic coupling, or conduction.
PLCs have a long durable life even in some challenging industrial conditions. - Maintenance
The PLC requires very low maintenance because they are robust.
Again, any maintenance electrician that may be assigned to the PLC control system can easily check the whole system because the connections are just easier, the program is highly readable, and it is standardized. - Historical Inertia
Programmable Logic Controllers are systems that have already proven themselves through the years of application and development.
It solved the major problem of control using the Relays, and it just continued to develop to suit companies that deal with a wide number of controlled devices.
Nowadays, PLCs can even be networked using peripherals such as the Ethernet, or other communication devices. This makes a more complex system out of the basic PLC setup. Also, because the PLC was used a very long time ago, companies are less likely to migrate to a microcontroller-based setup when the spares have been designed for PLC systems. Even so, new equipment for PLC is still compatible with the old ones that were manufactured years ago. This makes the PLC more cost-efficient in the long run than the microcontrollers. - Upfront costs are less important
In the long run, the PLC would produce less downtime than the microcontroller-based ones thus generating more assets for the company with a lower maintenance cost. Microcontrollers are cheaper, yes, but their qualities are just not the ones that companies are looking for in the industrial side. It’s quantity over quality with high productivity for them. Even though the upfront cost is high the maintenance cost is low.
Overall, PLCs are still king in the industrial side of automation and control systems. Although microcontrollers may be used in highly specialized systems, they are just not suited for the battles that the PLCs face in the industry. PLCs have less complexity, are cost-efficient, and are robust–that’s generally the reason why they are preferred for industrial control systems.