Tuesday, September 8, 2015

The Top 9 Advantages and Disadvantages of Internet SCADA or Web-Based SCADA




Technological developments influence the design of the control system. In the past, the control system based on serial data communication Point-to-Multipoint using a cable connection (RS232, RS485, BEL202), but this time the system was not able to accommodate the needs of control systems  that required rapid high mobility. Currently SCADA control design are already using web-based technology with the advent of Internet Protocol (IP). The system uses an IP tunnel over satellite, frame relay, fiber, radio to connect the SCADA network to the central office based on  individual IP so that it can be handled more quickly.
Is it true that internet SCADA or web-based SCADA technology profitable? What are the weaknesses and the potential risks that arise with this system? Let’s see this explanation below:

Internet SCADA or Web-Based SCADA

Advantages of Internet SCADA or Web-Based SCADA

1. Wide area connectivity and pervasive

At first, SCADA perform data communication via radio, modem or serial cable lines special. Currently SCADA data can be transmitted via Ethernet or TCP / IP. For ability mobile control system, computer networks for SCADA is a wide area connectivity without exposing sensitive data on the Internet, because once the connection has been established, it is then also the device can be responded.

2. Routable

In a SCADA-based control system design need supporting data communications mechanism utilities. It may deploy between the control center and the device in the field. Currently it takes a methodology that can be used for security implementations are primarily led by single vendors. Routable control system tend to focus on individual protocols and will give result environment that contains a mixture of security solutions that may only address some communication protocols at an increasing operational burden for the utility.

3. Parallel Polling

In the SCADA system Master Station sequentially scanning RTU to send short messages to each RTU can be determined if the RTU has information that needs to be reported. Scan cycle requires a relatively short time, approximately 7 seconds (maximum 10 seconds). Scan cycle that is scanning the entire remote terminals in the system. When Master Station give orders to an RTU, then all RTU will receive the order, but only the RTU whose address in accordance with a command that will run it. This system is called the parallel system polling.

4. Redundancy and Hot Standby

SCADA systems other advantage is the ability to limit the amount of data transferred between Master Station and RTU. This is done through a procedure known as exception reporting where only certain data that is sent when the data changes that exceed the limit setting, for example, the frequency value can only be considered to be changed if there is a change of 0.05 Hertz. So if there is a change that value is very small then it will be deemed not change the frequency. This is to anticipate the hysteresis properties of the system so that the actual frequency value can be read clearly.

5. Large addressing range

Decentralized system on SCADA requires a methodology that involves the user interface to data stored in the PLC memory addresses specified. When the data comes from a variety of sensors, controllers and different databases (which may be local or at varying locations connected), it requires a large addressing range. One of the benefits of web-based SCADA is having addressing large range.

6. Integration of IT to Automation and Monitoring Networks

SCADA facilities necessary to carry out the operation control in real-time. A SCADA system consists of a number of RTU (Remote Terminal Unit), a Master Station / RCC (Region Control Center), and the telecommunication networks of data between RTU and Master Station is the integration of IT systems and network control to get a good result performance.

7. Standardization

SCADA communication is regulated through a protocol, if the antiquity used a proprietary protocol in accordance with its SCADA manufacturers, now there are already some established protocol standards, so no need to worry about compatibility issues of communication again.

Disadvantages of Internet SCADA or Web-Based SCADA

8. IP Performance Overhead

IP address is the address given on computer networks and network equipment using TCP / IP. IP address consists of 32-bit binary numbers that can be written as four groups of decimal numbers. IP addresses are divided into five classes ranging class A through E. Web-based SCADA has a very large number of hosts. 1.xxx.xxx.xxx IP range. - 126.xxx.xxx.xxx, there are 16,777,214 (16 million) IP address

9. Security concerns

Currently SCADA-based control system is quite vulnerable if it is not done with the supervision and discipline. The initial solution was to use VPN (Virtual Private Networks) that can provide the required level of security, but if the connection is already connected to the wide area network the level of risk is high. Lately, news of Stuxnet is a very sophisticated program that was made with the code is so complex and able to exploit some loopholes operating system simultaneously with the target of attacks aimed at the large scale / industrial.

Conclusion

SCADA systems are designed to follow the latest technological developments. Formerly in the control system design with enough cable connection, but now the system is web based SCADA control. The use of web-based control systems have advantages and drawbacks. But in general, this system is more beneficial to the user for the technician in charge has the responsibility and discipline in running a good control system procedures.


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