What is SCADA?

SCADA system PLC industry.

SCADA system

SCADA system is a supervisory control and data acquisition software.
Its purpose is to control automation in industry gathering information from equipment like PLC communicating with a computer with SCADA software in real time. 

Work as HMI (Human Machine Interface) in a computer.

SCADA system supervisory:

The SCADA system begins with a supervisory concept. Management of industry data is important to an administration control system. Data acquisition from equipment in real time and organized reports improves company management solutions. Solutions like this, allied to industrial automation, result in quality improvements.

PLC is a Programmable Logic Controller. It is a hardware that can be used to control process in factory plan.
Its information can be passed to the PLC SCADA systems in a computer.
The SCADA can monitor in real time, control, record and generate reports from this information.

In a supervisory, the SCADA systems organize that information from the industrial factory through communication with PLC and data acquisition equipment. The information goes from users in a factory to general management.

The SCADA systems can monitor the industrial information through HMI panels in screens and reports with data from the recorded database.
The data acquisition can be stored in databases and distributed as needed.

SCADA panels can be replicated in the network via LAN / WEB. Several users are able to monitor the SCADA system supervisory.
The screen can be customized according to each case.
HMI objects are distributed in monitor creating control panels and plant schemes.
Animated objects pictures with graphic information are used to improve SCADA supervisory.
These objects can be displays, controls, bar graphs, gauges, valves, pumps, buttons, charts, etc.

SCADA control system with supervisory:

They can interact with SCADA users clicking and typing.
When these objects are used, information can be sent to PLC to control data acquisition in the factory.
SCADA data is passed to them. Users are able to get SCADA information through this.
The PLC SCADA can control the supervisory information through users and programming applications.
Scripts can be used for programming an application.
Automate systems getting input information, calculating and generating output data to the factory.

SCADA programming:

The SCADA systems are programmable according to each supervisory case.
If some data are included in some condition then information are sent to the PLC equipment.
And logical conditions define SCADA systems way to proceed the specific applications.
This programming can be made via script in SCADA.
The SCADA systems control automation in the factory.
Scripts are commands in several languages depending on the platform.
These commands can send and receive data to the SCADA system according to the each application case.


Data acquisition that came from PLC is made through networks like Ethernet and serial. Each PLC has protocols defined over these supervisory networks.

For example, Ethernet can be used with MODBUS TCP protocol.
There are several PLC with communication that can be used in SCADA automation.
These PLC can be distributed in a factory and connected.

The SCADA systems can centralize supervisory information of all PLC in net.

SCADA database:

SCADA system data are recorded in a database. This database can be SCADA proprietary or ODBC base.
Databases are tables of values that are used to store information about the system.
Each table has fields. Each field can be SCADA tag from PLC or variable.
Database fields may store values in number or text format according to the case.
Each register is a set of fields recorded.
Each scanning value is a register.

Inside this register, it can be stored a time field and header information before the values from data acquisition.
Auxiliary tables of products, recipes, customers, etc... can be used in SCADA system to improve.

PLC data acquisition passed to supervisory SCADA can be stored in this database.

SCADA reporting system:

After data stored in the database, reports can be generated.
Listing of the SCADA system tag fields. They can be formatted according to each case.
Several reports of PLC SCADA data acquisition are created to the manager.

Alarms can be set to trigger events. Limits maximum and minimum for each tag case.
Calculation according to process.
These SCADA system alarms are stored and recognized. Can be set in real time.
When data acquisition values reach alarm limits an event can be triggered.
The alarm is stored and informed to the SCADA system.


Another important issue is security. For example, remote applications must be secured from non-authorized external controls.

SCADA industrial solutions examples introduction:

There are several control fields in the industry. Metal, manufacturing, electric, food, chemical, automobile, etc...

Temperature SCADA system:

SCADA information of temperature can be monitored. Low, average or high temperatures are stored to assure process quality.
Limits and alarms are set to quality assurance.
If some temperature reaches limits, an occurrence is triggered for action and explanation in report system.
When SCADA recipes are set, SCADA system must control from start to finish of each process in the factory.
In temperature control, a setpoint must be defined for each case. Microcontrollers can be used to set data PID in the industry.

Pressure SCADA system.

SCADA information of pressure can be monitored. Limits and alarms are set to quality assurance.
If some pressure reaches limits, an occurrence is triggered for action and explanation in report system.
When SCADA recipes are set, SCADA system must control from start to finish of each process in factory company.

SCADA production counting.

SCADA system can do the counting of products on a production line.  Each product that passes to sensor sends to PLC a signal. A counter is used as a tag in SCADA to increase value to the number of items. These items can be products, objects, events, users, etc...

SCADA water treatment

In the SCADA system, each step of water treatment can be supervised and controlled. Levels, pressures, temperatures, events, alarms, etc...

Pumps can be monitored and triggered when needed. Valves also are controlled by SCADA.

Each variable can be reported in SCADA that was recorded in the database.