• A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that requires high reliability, ease of programming, and process fault diagnosis.
• PLCs can range from small modular devices with tens of inputs and outputs (I/O), in a housing integral with the processor, to large rack-mounted modular devices with thousands of I/O, which are often networked to other PLC and SCADA systems.[1] They can be designed for many arrangements of digital and analog I/O, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact.
• PLCs were first developed in the automobile manufacturing industry to provide flexible, rugged, and easily programmable controllers to replace hard-wired relay logic systems. Dick Morley, who invented the first PLC, the Modicon 084, for General Motors in 1968, is considered the father of PLC.
• A PLC is an example of a hard real-time system since output results must be produced in response to input conditions within a limited time, otherwise unintended operation may result. Programs to control machine operation are typically stored in battery-backed-up or non-volatile memory.

• Human Machine Interface, often known by the acronym HMI, refers to a dashboard or screen used to control machinery. Line operators, managers, and supervisors in the industry rely on HMIs to translate complex data into useful information.
• For example, they use HMIs to monitor machinery to make sure it’s working properly. Easy-to-understand visual displays give meaning and context to near real-time information about tank levels, pressure and vibration measurements, motor and valve status, and other variables.
• But the advanced capabilities of today’s HMIs enable managers and supervisors to do much more than control processes. Using historical and trending data they offer vast new opportunities to improve product quality and make systems more efficient.
• For all these reasons, HMIs play a key role in the smooth and effective running of factories and manufacturing operations. However, not all HMIs are created the same.

• SCADA (supervisory control and data acquisition) is a category of software applications for controlling industrial processes, which is the gathering of data in Real Time from remote locations in order to control equipment and conditions. SCADA provides organizations with the tools needed to make and deploy data-driven decisions regarding their industrial processes.
• One of the most commonly used types of industrial control systems, SCADA can be used to manage almost any type of industrial process.
• SCADA systems include hardware and software components. The hardware gathers and feeds data into field controller systems, which forward the data to other systems that process and present it to a human-machine interface (HMI) promptly. SCADA systems also record and log all events for reporting process status and issues. SCADA applications warn when conditions become hazardous by sounding alarms.

A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply. The VFD also can control the ramp-up and ramp-down of the motor during start or stop, respectively. Even though though the drive controls the frequency and voltage of power supplied to the motor, we often refer to this as speed control, since the result is an adjustment of motor speed. There are many reasons why we may want to adjust this motor speed.

• To Save energy and improve system efficiency
• Convert power in hybridization applications
• Match the speed of the drive to the process requirements
• Match the torque or power of a drive to the process requirements
• Improve the working environment
• Lower noise levels, for example from fans and pumps
• Reduce mechanical stress on machines to extend their lifetime
• Shave peak consumption to avoid peak-demand prices and reduce the motor size required

• Set tasks, and receive data,   The servo drive receives a command signal from a control system, amplifies the signal, and transmits electric current to a servo motor to produce motion proportional to the command signal. Typically, the command signal represents a desired velocity, but can also represent a desired torque or position. A sensor attached to the servo motor reports the motor's actual status back to the servo drive. The servo drive then compares the actual motor status with the commanded motor status. It then alters the voltage, frequency, or pulse width of the motor to correct for any deviation from the commanded status
• In a properly configured control system, the servo motor rotates at a velocity that very closely approximates the velocity signal being received by the servo drive from the control system. Several parameters, such as stiffness (also known as proportional gain), damping (also known as derivative gain), and feedback gain, can be adjusted to achieve this desired performance. The process of adjusting these parameters is called performance tuning.
• Although many servo motors require a drive specific to that particular motor brand or model, many drives are now available that are compatible with a wide variety of motors, and manage projects.