I’m here to discuss about the field of industrial automation and the sub-fields related to it. We will also learn about the industrial automation jobs and opportunities in coming years.
Scope of Industrial Automation
Industries and factories are the most essential requirements of the world.
These industries and factories are divided into various sub-factors like manufacturing, production, power plants, oil and gas industries, meat cutting, bottle filling plants, etc.
These industries involve a lot of engineering domains like electrical and electronics, mechanical, instrumentation, etc.
As we know that industries require a lot of space and various work locations (especially some remote locations), so it is feasible to control and monitor them with the help of PLC and SCADA systems.
Introduction of PLC and SCADA
Importance of PLC in industrial automation jobs
What is the importance of PLC in industries?
PLC is a programmable logic controller which is used to control the industries with the help of input (I) and output (O) devices.
PLC is an industrial controlling device that uses input and output modules to interface with the field devices and controls them depending upon the plant requirements.
It will be having a CPU for processing, generally termed as the ‘Master control unit’ and for the purpose of communication with the input and output modules.
The communication process varies from PLC to PLC depending upon the make or brands of PLC.
The PLC unit consists of the following hardware components:
- Central processing unit (CPU)
- Input (I) and output modules (O) (Analog type and Digital type)
- Power supply (PS)
- Back plane
- Communication modules (depending upon the type of PLC)
- Ethernet switches
- Media converters (depends on the requirements)
- Ethernet cables (depends on the type of communications)
The PLC unit consists of the following useful 5 software PLC languages:
- Ladder diagram or ladder logic (LD)
- Structure text (ST)
- Function block diagram (FBD)
- Sequential function charts (SFC)
- Instruction list (IL)
We will be using some communication protocols for the communication between PLC and SCADA. Some of them are listed below:
- Ethernet TCP/IP
- Modus RTU
- Modbus TCP/IP
- ProfiBus and many more.
Check here 31 Most Used PLC Communication Protocols in Industries.
For the long distancing communication there are some limitations for Ethernet cables, so industries are making use of optical fiber cables (OFC) for long-distance communication. Because, OFC cables are robust, reliable and no limitations for distance.
For the interfacing of Ethernet with OFC, industries use media converters and line interface unit (LIU) for the transmission of data between remote nodes and master PLC.
Along with the PLC automation industries such as oil and gas make use of a remote terminal unit (RTU) which is portable in size and can be installed at most of the remote locations where it is hard for the workers or employees to monitor and control the plant.
Importance of SCADA in Automation
What are the roles of SCADA in industrial automation jobs?
SCADA is a supervisory control system where the operators/engineers can control and monitor the entire plant with the help of the program written in the PLC programming terminal.
PLC or RTU is communicated to SCADA with the help of the communication protocols which is used according to the project requirement.
Generally, SCADA systems will be of the following types:
- Server or Client system
- Master or Slave system
EWS generally called as ‘Engineering Work System’ where the PLC programming will be done and the remote work station (RWS) where the operators can control and monitor the plants or industries, and the SERVER where all the client systems (RWS) gets the data.
This setup will be placed in the central control room (CCR). Apart from these systems industries or factories also make use of some industrial devices like media converters, GPRS modem, Ethernet switches, LAN tester for some connectivity check between Ethernet cables.
The data will be transmitted from nodes (salve PLC) to the master PLC and from the master PLC
through the SCADA server.
The whole process of communication will be done through IP addresses assigned to the specified node or server or workstations.
They must be in the same domain to communicate with each other (not mandatory in all cases) some devices communicate through different domains but through gateway addresses.
Introduction to Field Devices
To control and monitor the plants or industries field devices (instruments or controllers) are necessary.
So according to the industrial point of view transmitters are the ideal instruments for an industry to get the data.
The listed instruments are the feasible devices for the transmission of analog data:
- Flow Transmitters (FT)
- Level Transmitters (LT)
- Temperature Transmitters (TT)
- Pressure Transmitters (PT)
- Differential Pressure Transmitters (DPT)
Along with the transmitters the field devices also consist of the digital controlling devices like:
- Motor operated valves (MOV)
- Level controllers
These transmitters transmit the data in the form of a current (4-20 mA). And this current will be sent to the respective node (slave PLC) and through that PLC it will be transmitted to the master PLC.
This ‘current’ value will be scaled in the form of counts (0-32000) and sent to the SCADA server depending upon the project requirement and it will be scaled in server-based upon the further requirement.
These transmissions will be done through the Ethernet cables, OFC cables, and media converters.
A leak detection system (LDS) is a system used to detect any leaks in the gas pipelines which is easy for the technician to rectify the leak.
Operation of MOV’s and Pumps
MOV’s and pumps operate based on the relay contacts. The power supply of these instruments will depend on their rating or capacity.
They can be controlled from the CCR or from the local itself. These R or L indications are also sent to the SCADA through the PLC node.
These are the digital indications depending upon the type of instruments. Digital signals are divided into two types. They are:
- Digital input (DI)
- Digital output (DO)
DO is the command used to drive the motor or MOV which is used to change the state (from 0 to 1) of the instrument.
Generally, MOV’s and pumps are of double digital types (four states). While the indications of the status of the operations of the instruments will be considered as the digital inputs (DI).
The sequence of operation of the DO command will be as follows:
First the DO command will be given from the SCADA RWS PLC relay of the instrument. Then it will operate according to the condition of the PLC logic and the feedback will be sent to the SCADA server through the 4-20 mA or 24V DC re-transmission wire.
Development of the Automation Project
For the execution and development of a project the following sequence is considered:
- Preparing the line diagram of the project using with the necessary equipment involved in that.
- Piping and instrumentation diagrams (P & ID) if the project involves pumps and valves.
- Preparing the outlay or overview of the project using E-PLAN or AutoCAD software.
- Analyzing the number of inputs required for the project and preparing them in an excel sheet to create the tags.
- Installation of the PLC panels in the specified location suitable for the field devices to communicate.
- Installation of the instruments and field devices that are incorporated in the project.
- Wiring the field devices to the PLC panel terminal breakers (TB’s).
- Developing the logic according to the working of the plant and the requirement of the project.
- Set up of the SCADA server-client system and establishment of communication between PLC and SCADA.
- Laying of the cables for long-distance communication with the remote PLCs.
- Checking whether all the inputs are working properly according to the logic by doing a FAT procedure.
- After the FAT, proceed with the SAT to verify at the client location.
Revolution of Industrial Automation
Now industrial automation has evolved in different fields, ‘Home automation’ is also developing its ideas based on the technology used in industrial automation with the use of compact PLCs.
Read more: Compact PLC and Modular PLC
Now industry 4.0, IOT has merged with industrial automation to enhance its technology and make it more emerged in the practical world.
Career in Industrial Automation Jobs
Industrial automation has whooping career opportunities and jobs in the coming few years as the engineers or technicians required for this field are in scarcity.
Core industries or factories need to be automated for reliable and efficient working. So there will be huge industrial automation job opportunities.
With the evolving of the industrial revolution, one can trust that industrial automation will be the next big thing in the modern world.
I completed BTech in electrical & electronics engineering. Currently, I’m working as a process automation engineer. I want to explore my knowledge in the field of industrial automation and so I find writing this kind of article defines it more purposeful.