Scada


SCADA 

The SCADA concept was developed as a universal means of remote access to a variety of local control modules, which could be from different manufacturers allowing access through standard automation protocols. In practice, large SCADA systems have grown to become very similar to distributed control systems in function, but using multiple means of interfacing with the plant. They can control large-scale processes that can include multiple sites, and work over large distances. It is one of the most commonly-used types of industrial control systems, however there are concerns about SCADA systems being vulnerable to cyberwarfare/cyberterrorism attacks.
Supervisory control and data acquisition (SCADA) is a control system architecture that uses computers, networked data communications and graphical user interfaces for high-level process supervisory management, but uses other peripheral devices such as programmable logic controllers and discrete PID controllers to interface to the process plant or machinery. The operator interfaces which enable monitoring and the issuing of process commands, such as controller set point changes, are handled through the SCADA supervisory computer system. However, the real-time control logic or controller calculations are performed by networked modules which connect to the field sensors and actuators.

SCADA

Nell'ambito dei controlli automatici, l'acronimo SCADA (dall'inglese "Supervisory Control And Data Acquisition", cioè "controllo di supervisione e acquisizione dati") indica un sistema informatico distribuito per il monitoraggio elettronico di sistemi fisici.

Descrizione[modifica | modifica wikitesto]

Tipicamente, i sistemi di tipo SCADA sono utilizzati come sistemi di controllo in ambito industriale per il monitoraggio e controllo infrastrutturale o di processi industriali e sono composti da:
  • uno o più sensori, che effettuano misurazioni di grandezze fisiche di interesse sul sistema in oggetto;
  • uno o più microcontrollori, che possono essere PLC o microcomputer, che, continuativamente o a intervalli di tempo, effettuano misurazioni tramite i sensori a cui sono collegati e memorizzano i valori misurati in una memoria locale;
  • un sistema di telecomunicazione tra i microcontrollori e il supervisore. Può essere una rete di computer, oppure un insieme di linee seriali; può essere basato su cavo o su radio. Nei casi tipici sono cavi seriali digitali per brevi distanze, doppini di tipo telefonico a cui sono collegati o dei modem a bassa velocità, per medie distanze, oppure ponti radio o telefoni cellulari, per grandi distanze;
  • un computer supervisore (es. server), che periodicamente raccoglie i dati dai microcontrollori, li elabora per estrarne informazioni utili, memorizza su disco i dati o le informazioni riassuntive, eventualmente fa scattare un allarme, permette di selezionare e di visualizzare su schermo i dati correnti e passati, eventualmente in formato grafico, ed eventualmente invia informazioni selezionate al sistema informativo aziendale.
Un sistema SCADA utilizza una rete di telecomunicazioni geografica (Wide Area Network). Sistemi simili, ma basati su una rete di comunicazione locale (Local Area Network) sono propriamente definiti DCS (Distributed Control System): tipici esempi sono i sistemi di controllo e supervisione di impianti industriali.
I sistemi DCS sono ad un livello superiore, potendo, oltre che supervisionare, anche comandare i sistemi di automazione, cosa che ai sistemi SCADA è invece inibita.

Comments

Post a Comment

Popular posts from this blog

SCADA architecture development

Image
SCADA architecture development SCADA systems have evolved through four generations as follows: Early SCADA system computing was done by large minicomputers. Common network services did not exist at the time SCADA was developed. Thus SCADA systems were independent systems with no connectivity to other systems. The communication protocols used were strictly proprietary at that time. The first-generation SCADA system redundancy was achieved using a back-up mainframe system connected to all the Remote Terminal Unit sites and was used in the event of failure of the primary mainframe system. Some first generation SCADA systems were developed as "turn key" operations that ran on minicomputers such as the PDP-11 series made by the Digital Equipment Corporation. SCADA information and command processing was distributed across multiple stations which were connected through a LAN. Information was shared in near real time. Each station was respons...
Keep reading

Security issues

Security issues the lack of concern about security and authentication in the design, deployment and operation of some existing SCADA networks the belief that SCADA systems have the benefit of security through obscurity through the use of specialized protocols and proprietary interfaces the belief that SCADA networks are secure because they are physically secured the belief that SCADA networks are secure because they are disconnected from the Internet See also DNP3 IEC 60870 Modbus BACnet LonWorks SCADA systems that tie together decentralized facilities such as power, oil, gas pipelines, water distribution and wastewater collection systems were designed to be open, robust, and easily operated and repaired, but not necessarily secure. The move from proprietary technologies to more standardized and open solutions together with the increased number of connections between  systems, office networks and the Internet has made them m...
Keep reading

SCADA and PLC commercial integration

SCADA and PLC commercial integration Since about 1998, virtually all major PLC manufacturers have offered integrated HMI/SCADA systems, many of them using open and non-proprietary communications protocols. Numerous specialized third-party HMI/SCADA packages, offering built-in compatibility with most major PLCs, have also entered the market, allowing mechanical engineers, electrical engineers and technicians to configure HMIs themselves, without the need for a custom-made program written by a software programmer. The Remote Terminal Unit (RTU) connects to physical equipment. Typically, an RTU converts the electrical signals from the equipment to digital values such as the open/closed status from a switch or a valve, or measurements such as pressure, flow, voltage or current. By converting and sending these electrical signals out to equipment the RTU can control equipment, such as opening or closing a switch or a valve, or setting the speed of a pump. Communication infrastructure...
Keep reading