INDUSTRIAL AUTOMATION
Today’s highly increasing competitiveness over the industry demands high quality and most consistent products with a competitive price. To address this challenge number of industries considering various new product designs and integrated manufacturing techniques in parallel with the use of automated devices.
One of the remarkable and influential moves for getting the solutions of above mentioned challenge is the industrial automation. Industrial automation facilitates to increase the product quality, reliability and production rate while reducing production and design cost by adopting new, innovative and integrated technologies and services.
What is Industrial Automation?
Automation takes a step further mechanization that uses a particular machinery mechanism aided human operators for performing a task. Mechanization is the manual operation of a task using powered machinery that depends on human decision making.
On the other hand, automation replaces the human involvement with the use of logical programming commands and powerful machineries.
Hierarchy of an Industrial Automation System
Industrial automation systems can be very complex in nature, having large number of devices working in synchronization with automation technologies. The figure below describes the hierarchical arrangement of the automation system consisting of different hierarchical levels.
Field Level
It is the lowest level of the automation hierarchy which includes the field devices like sensors and actuators. The main task of these field devices is to transfer the data of processes and machines to the next higher level for monitoring and analysis. And also it includes the controlling of process parameter through actuators. For instance, we can describe this level as eyes and arms of a particular process.
Sensors convert the real time parameters like temperature, pressure, flow, level, etc into electrical signals. This sensor data further transferred to the controller so as to monitor and analyze the real time parameters. Some of the sensors include thermocouple, proximity sensors, RTDs, flow meters, etc.
On other hand actuators converts the electrical signals (from the controllers) into mechanical means to control the processes. Flow control valves, solenoid valves, pneumatic actuators, relays, DC motors and servo motors are the examples of actuators.
Control Level
This level consists of various automation devices like CNC machines, PLCs, etc., which acquires the process parameters from various sensors. The automatic controllers drive the actuators based on the processed sensor signals and program or control technique.
Programmable Logic Controllers (PLCs) are most widely used robust industrial controllers which are capable of delivering automatic control functions based on input from sensors. It consists of various modules like CPU, analog I/O, digital I/O and communication modules. It allows the operator to program a control function or strategy to perform certain automatic operation on process.
Supervising and Production Control Level
In this level, automatic devices and monitoring system facilitates the controlling and intervening functions like Human Machine Interface (HMI), supervising various parameters, setting production targets, historical archiving, setting machine start and shutdown, etc.
Mostly, either Distribution Control System (DCS) or Supervisory Control and Data Acquisition (SCADA) HMIs are popularly used in this level.
Information or Enterprise Level
This is the top level of the industrial automation which manages the whole automation system. The tasks of this level include production planning, customer and market analysis, orders and sales, etc. So it deals more with commercial activities and less with technical aspects.
And also industrial communication networks are most prominent in industrial automation systems which transfer the information from one level to the other. So these are present in all the levels of automation system to provide continuous flow of information. This communication network can be different one level to the other. Some of these networks include RS485, CAN, DeviceNet, Foundation Field bus, Profibus, etc.
From the above hierarchy we can conclude that there is continuous information flow from high level to low level and vice-versa. If we assume this graphical way, it is like a pyramid in which as we go up, the information gets aggregated and while going down, we get detailed information about the process.
Fixed or Hard Automation
This type of automation is employed to perform fixed and repetitive operations in order to achieve high production rates. It uses special purpose or dedicated equipment to automate the fixed sequence assembling or processing operations. Once it is employed, it is relatively hard to change or vary the product design. Therefore, it is inflexible in providing product variety, but increases the efficiency with higher production rate and reduces unit cost.
Some of these automated systems are distilled process, paint shops and conveyors.
Programmable Automation
In this automation, a specific class of product changes and also assembling or processing operations can be changed with the modification of control program in the automated equipment.
This automation is best suited for batch production process where product volume is medium to high. But in this, it is hard to change and reconfigure the system for a new product or sequence of operations. Therefore, new product or reconfigure of sequence of operations requires a long setup.
Examples of this automation system are numerically controlled machines, paper mills, steel rolling mills, industrial robots, etc.
Flexible or Soft Automation
This automation system provides the automatic control equipment that offers a great flexibility for making changes in the product design. These changes can be performed quickly through the commands given in the form of codes by the human operators.
This automation allows the manufacturers to produce multiple products with different ranges as a combined combination process rather than separate.
Some of the examples of this automation system are automatic guided vehicles, automobiles, and multipurpose CNC machines.
