In this article, we will learn the difference between PLC and SCADA. PLC and SCADA systems exist at an advanced level in the industrial automation world. We can not complete our automation skill set without these systems because, in the present age, almost all types of industries can not survive without PLC and SCADA systems.
PLC is a combination of software and hardware, which is connected with field devices and controls the operation according to given programming while the SCADA is only software that provides the help to control and supervise this process as well as acquire the data record.
Functionality of PLC
Each PLC brand has its own software which provides help to program and configure to PLC for different operations. On the other hand, all the field devices (sensors actuators and VFDs) are connected with plc through different types of communication protocols like Modbus. In simple words PLC acts like a mind that takes the analog and digital signals through field devices and gives the instructions according to programming while field devices do the work as eyes and hands, these devices collect the data from the field and execute the operation according given instructions.
Functionality of SCADA
SCADA is just software, which is a major difference between PLC and SCADA, that is connected with PLC controllers, it provides a graphical view so we can supervise the process through it and gives access to pass the different instructions to controllers. Moreover, the SCADA system acquires data from PLC controllers and saves it in the connected database, The SCADA system also shows this data in different types of charts, where we can straightforwardly analyze the data.
What is the role of PLC in SCADA?
In the SCADA system, PLC is used as a controller with the programming file In its memory, PLC performs the operation according to its programming logic. PLC also receives digital and analog signals from the field with the help of field I/Os. Other than that PLC sends this data to the SCADA system, where SCADA shows this data in graphics form. The difference between PLC and SCADA in simple words, in the SCADA system, a lot of PLCs work at the same time these PLCs control different processes in a plant, we can not monitor all PLCs directly so, we use SCADA software to supervise, control, and record the data of these PLCs.
Can PLC work without SCADA?
PLC can work without SCADA because wherever we don’t need of graphical view, data record or control, PLC can be used without SCADA, it will perform its operation according to logic but the SCADA system is useless without PLC because in SCADA system plc is the main unit which is controlled by SCADA. If we neglect the plc from this system, the SCADA system has not any use.
Comparison Between PLC and SCADA
PLC
SCADA
PLC is a hardware device which used to control or automate different processes and machinery.
SCADA is a software that provides a graphical view, supervisory control, and, record the data.
PLC works in lower stream.
SCADA works in the upper stream.
PLC receives input and output signals from field I/Os to control related machines or processes.
SCADA communicates with different PLCs at the same time and provides a graphical view of the controlling process.
The different programming languages (Ladder logic, FBD) used to program the PLC.
In SCADA different graphical libraries are used to make the graphical view.
PLC is used for real-time control of the process or machine by programming.
SCADA is used for real-time monitoring, storing the data for analysis, showing the alarms, and taking corrective actions.
PLC is used for specific machine and process
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Which should I learn first PLC or SCADA?
In industrial automation plc is a first step to learn, you can start from plc programming because Scada comes in the upper layer of automation. PLC hardware understanding, PLC wiring methods, and PLC basic programming will be the initial steps of your dream journey then you can go ahead for the SCADA system.