SCADA - Supervisory Control and Data Acquisition

Introduction of SCADA

Prior to the introduction of SCADA, producing floors and modern plants depended on the manual control and screen utilizing press catches and simple hardware. As the size of the enterprises and assembling units developed in size, they began utilizing transfers and clocks, that gave administrative control to a limited degree. Shockingly, transfers and clocks had the option to tackle issues just with insignificant computerization usefulness and reconfiguring the framework was troublesome. Thus, a progressively productive and completely robotized framework was required by all enterprises. 

PCs were produced for modern control purposes in the mid-1950s. Gradually, the telemetry idea was presented for virtual correspondence and transmission of information. Around the year 1970, the term SCADA was begotten alongside the development of Microprocessors and PLC ideas. Along these lines, this aided for the advancement of a completely robotized framework, that can be utilized remotely in Industry. As years moved by, in the mid-2000s, conveyed SCADA frameworks were created. 

Current SCADA frameworks appeared that permitted us to control and screen constant information anyplace on the planet. The ongoing association blasted up the business and took the development of enterprises to more prominent statures. Regardless of whether the administrator didn't have a lot of information on programming improvement, he had the option to oversee present-day SCADA frameworks.

What is SCADA?

SCADA stands for Supervisory Control and Data Acquisition. It enables engineers, supervisors, managers and operators to view and interact with the working of the entire operation through graphical representation (Human Machine Interfaces), networked data communication and computers of their production process. It constantly gathers data from the plant in real-time, stores and processes it in the database, evaluates and generates alarms and displays information to plant operators and can issue an instruction to Programmable Logic Controller (PLC) and PID controllers on the plant floor.

Objectives of SCADA

• Monitor: SCADA systems continuously monitor the physical parameters
• Measure: It measures the parameter for processing
• Data Acquisition: It acquires data from RTU, data loggers, etc
• Data Communication: It helps to communicate and transmit a large amount of data between MTU and RTU units
• Controlling: Online real-time monitoring and controlling of the process
• Automation: It helps for automatic transmission and functionality.

Functions of SCADA Systems

The SCADA system is a collection of hardware and software components that allows the manufacturing units to perform specific functions. Some of the important functions include

• To monitor and gather data in real-time
• To interact with field devices and control stations via Human Machine Interface (HMI)
• To record systems events into a log file
• To control manufacturing process virtually
• Information Storage and Reports

SCADA

Different types of Software used for SCADA

Citect SCADA – Schneider Electric

A compact, flexible and reliable SCADA software developed by Schneider Electric. The latest product released by them is Vijeo Citect (version7.10) Citect SCADA is still one of the commonly used SCADA technologies and you certainly need to learn about this platform as a SCADA developer. It has actually become part of the SCADA alternatives for Wonderware.

InTouch – Wonderware

InTouch, which has become one of the largest SCADA suppliers on the market, comes from Wonderware, now owned by Schneider Electric. Although Wonderware is relatively new to the market, it is quickly gaining popularity. The Wonderware system platform is a SCADA system with many “plug-and-play” parts that is modular and very versatile. Because of the modularity of this scheme, you can readily customize it to your requirements if you choose this SCADA software. The benefit of In Touch is that they use open standards of communication and can operate with most PLC systems.

Experion SCADA – Honeywell

Honeywell is commonly used in PLC systems (particularly in the US). They are also a big player in the SCADA market, providing a software platform for programming SCADA and HMI systems. You can either use their software for a stand-alone SCADA scheme or use it with Honeywell’s PLC platform (e.g. C200 and C300 platform) as well as RTU’s like Control Edge RTU. Although Honeywell’s SCADA software works are optimized to communicate with other Honeywell products (e.g. PLCs and RTUs), it will still work when paired with non-Honeywell products.

iFIX – General Electric

General Electric (GE) is one of the world’s largest manufacturing businesses, is also a significant player in the SCADA market. IFIX is one of their software solutions and it is a very flexible SCADA system. The advantage of using iFIX is its ability to develop screens quickly with HTML5. Another reason is the many drivers that allow you to set up networked and distributed systems, allowing you to connect and exchange information with most contemporary PLCs. GE also have their own branded PLCs – but a GE SCADA system does not require these GE PLCs to function correctly.

Ignition – Inductive Automation

Ignition is a SCADA scheme that uses the latest IoT architecture to its full potential. Ignition from Induction Automation is a very nice option if you want a system that is up-to-date with all Industry 4.0 norms and techniques. Ignition is relatively new to the SCADA industry compared to some of the veteran systems. That said between Ignition’s IoT integrations and the fact that they work with most PLC systems, Ignition has been chosen by many businesses as their SCADA solution.

SIMATIC WinCC V7 – Siemens

The Siemens SCADA system has been around for many years, and is known as “WinCC”. Siemens is one of the largest players in the PLC and SCADA industry, and many businesses use the Siemens platform. Siemens is a huge company that has been evolving their PLC and SCADA platforms over the years to adopt modern technologies. The fact that they are a large and veteran player in the SCADA industry gives many businesses confidence in entrusting them with their SCADA applications.

RS View 32 – Rockwell Automation

Monitoring and controlling automation machines and processes demands versatility and the scalability to connect to a host of open technologies. RSView®32™ is an integrated, component-based HMI for monitoring and controlling automation machines and processes. RSView32 expands your view with open technologies that provide unprecedented connectivity to other Rockwell Software products, Microsoft products, and third-party applications.

What is Tag?

A tag database consists of records called tags. ( A tag similar to a symbol in PLC programming terminology.) In the tag database, you define the data you want RSView32 to monitor. You can organize tags into groups using folders. This speeds up database creation because you can duplicate a folder and its tag in a single operation.

Types of Tags:-

• Analog: Stores numerical values
• Digital: Stores simple ON/OFF information
• String: Stores alphanumeric characters

The data sources for a tag can be:-

Device:- receives its data from PLCs through a direct driver via communication driver or a DDE server or OPC server. It can also receive data from other windows program through a DDE or OPC server

Memory:- Data comes only from the value table rather than a PLCs or other program.

System tags:- The third type of tag, the system tag, is created.

Features of SCADA

Dynamic Process Graphic:-

It developed in SCADA software should resemble the process mimic. SCADA should have a good library of symbols so that you can develop the mimic as per requirement. Once the operator sees the screen he should know what is going on in the plant.

Real-time and Historical Trend:-

The trends play a very important role in the process operation. If you batch fails or the plant trips, you can simply go to the historical trend data and do the analysis. You can have a better look at the parameters through the trends. 

Example:-

We commission a SCADA system for Acid Regeneration plant where the plant has to be operated on 850-deg temperature. If the operator operates a plant at 900 deg you can imagine how much additional LPG he is putting into the reactor. Again what will happen to the bricks of the reactor? So the production manager's first job will be to go through the trends of how the operators are operating the plant. Even when the plant trips there are more than 25 probable reasons for the same but if you go through the historical trends, its very easy to identify the problems.

Visibility:-  

To make any device invisible when it is at rest by applying expression on them.

Example:-
Tagname:- a

                    a < = 25 

                    a  >  25 & a < = 25

                    a  > 50 & a < = 50

                    a  > 75

* Always gives visibility spontaneously.

Orientation:-

To rotate any device in the counter-clockwise (CCW) or clockwise (CW) direction from 0 deg to 360 deg angle.

X-axis and Y-axis

   Horizontal           

                                  Orientation                                      X                                          Y

•                           Centre 0                                            0                                           0
•                           A is centre                                        -5                                          0
•                           B is centre                                         5                                           0

    Vertical

                                  Orientation                                      X                                          Y

•                           Centre 0                                            0                                           0
•                           A is centre                                         0                                          -5
•                           B is centre                                         0                                           5

      Rectangle

                                  Orientation                                      X                                          Y

•                           Centre 0                                            0                                           0
•                           A is centre                                         5                                        -10
•                           B is centre                                        -5                                        -10
•                           C is centre                                        -5                                         10
•                           D is centre                                         5                                         10

Alarms:-  

To indicate to the operator instantly when something goes wrong. It is often equally important to have a record of alarm and whether an alarm was acknowledged. 

An alarm can signal that a device or process has stopped operating within a pre-defined limit or it can indicate breakdown, wear, or process malfunction.

Deadband:- 

The value defines the range after which a high-low alarm condition return to normal.

Recipe Management:- 

Most of the plants are manufacturing multi-products. When you have different products to manufacture, you just have to load the recipe for that particular product.

Device Connectivity:- 

You will find there are hundreds of automation hardware manufacturers like  Modicon, Siemens, Allen-Bradley, Yokogawa, ABB and Rockwell Automation. Everybody has there own way of communication or we can say they have there own used in automation. It should not happen that for Modicon I am buying one software and for Siemens another one. The software like Aspic or Wonderware has connectivity to almost all hardware used in automation.

Database Connectivity:- 

Most manufacturing units go for Enterprise Resource Planning (ERP) or Management Information System (MIS).

1). EXCEL →                2003                 →      Filename.XLS
                                       2007                 →      Filename.XLS X

2). Tag name →              I/O REAL

3). Access →                  NAME → Filename
                                       MODE → NOT
                                       APP  →     EXCEL
                                      TOPIC →  Filename.XLS
                                                         Filename.XLS X

4). Item (Place)     → R1C1
                                   I/O Communication

5). D.D.E. (Microsoft Dynamic Data Exchange)

It is a communication protocol developed by Microsoft to allow application (INTOUCH) in the window's environment to send/receive data and instruction to/from each other. It implements a client-server relationship between two concurrently running applications. The server application provides the data and accepts requests from any other application interested in its data. Requesting applications are called Clients. Some applications such as INTOUCH and Microsoft EXCEL can simultaneously be both a client and a server.

MS EXCEL  SERVER   → To provide data and accept requests from any other application.
INTOUCH   CLIENTS →  It can be linked by DDE, NetDDE and Wonderware suite link protocol.

Net DDE → It extends the standard Window DDE functionality to include communication over local area networks and through serial ports. Network extensions are available to allow DDE links between an application running on different computers connected via network or modems.

Dynamic Data Exchange Excel

Security:-

It is one facility people generally look for. You can allocate certain facilities or features to the operator, process people, engineering dept & maintenance dept. For example, operators should have access to changing the application developed.

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Application of SCADA

Production Dept:-

• Real-time production status: manufacturing status is updated in real-time in direct communication to operator and control device.
• Production schedules: production schedules can be viewed and updated directly.
• Production information mgt.: production specific information is distributed to all.

Quality Dept:-

• Data integrity and quality control are improved by using a common interface.
• It is an open platform for statistical analysis.
• Consolidation of manufacturing and lab data.

Maintenance Dept:-

• Improved troubleshooting and debugging: direct connection to a wide variety of devices, displays improves troubleshooting reduces diagnostic/debugging time.
• The plant can be viewed remotely. Notification can include pagers, e-mails and phones.
• Co-ordination between maintenance and management reduces unscheduled downtime.

Enterprise Information:-

• Corporate information and real-time production data can be gathered and viewed from anywhere within your operations.
• User-specific information ensures better-informed decisions
• Data exchange with standard databases and Enterprise systems provides integrated information solutions.

Engineering Dept:-

• Integrated Automation solutions reduce design and configuration time.
• The common configuration platform offers flexibility for constant configuration in all areas.
• Capable of connecting to a wide variety of systems. Reduces start-up time and system training with industry proven open interfaces.

Manufacturing Dept:-

• Unscheduled downtime is reduced due to swift alarm detection event-driven information.
• Makes operations easier and more eatable with its real-time functionality.
• Secured real-time operations are maintained with windows.