Industrial automation systems have developed over time and Programmable Logic Controllers or PLCs have made it possible for internal components of automated units to function as one unit. There are many systems that use PLC today. A programmable logic controller is a computer device that can be used for industrial control systems. It is programmed to control different devices and industrial equipment. It does this by making connections between each unit so that they all function together.There is great potential for PLCs to become more diverse with the advancement of industrial control systems.

There is a computer processor that powers the PLC and this is what collects all the inputs in order to provide an output that we require. There can be digital or analog inputs. There are companies such as megatronic power control systems that specialise in the programming of these units. The programing teams will ensure that the system is programmed in such a way that it can suit the application required by the client. There are different industries where PLCs are used such as manufacturing lines, conveyor systems etc. PLC allows for more options to be created in a system. The clients are able to look for more complex control systems which will allow them to make their existing systems more efficient.

Inputs from different sources are scanned by the PLC and this information is internalized. The desired output is known therefore it can easily execute its programming in order to achieve it. There will be a control network that the PLC communicates with to provide useful information. There are diagnostic tests run to make sure that the PLC is working efficiently. If there is a bigger input in the beginning, the PLC programme should be sufficiently large in order to scan it. Also, for larger inputs, a much longer scan cycle will be required. However, it takes milliseconds for the scan cycle to complete so these systems can be very fast. If the scan cycle needs to be sped up, a programmable automation controller can be used for specialized processing tasks. User programming plays a large role in how well the PLC runs. So the efficiency of the system and all the potential benefits will be determined by the level of programming.

A PLC is quite similar to a small computer that is highly specialized for a task. It has much of the same components but it is built to fulfil a role in an industrial environment. There are different classifications of PLCs as well that depends on their capabilities and features. There are compact PLCs, small-medium-large PLCs and modular PLCs. A compact PLC can be packed into a small unit as the name implies. The number and the types of inputs and outputs for the device will be decided by the manufacturer. Modular PLCs are made up of multiple parts that are plugged onto one rack. They vary in their processing power and functions. Some of the basic components of PLCs are the central processing unit, input/output (I/O) section, rack and power supply.