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Over the years, information system security professionals developed a number of generally accepted best practies to protect networks and computing infrastructures from malicious attacks. However, these practices cannot be applied directly to SCADA systems without accounting for the different requirements of IT and SCADA systems. The following list provides examples of IT best practices and the state of their application to SCADA systems: - Audit and monitoring logs: After-the-fact analysis of audit trails is a useful means to detect past events. Monitoring, on the other hand, implies real-time capture of data as a system is operating Both techniques are successfully employed in IT systems.Their application to SCADA systems will yield benefits similar to those derived from their use in IT systems. BEcause of the varying ages and sophistication of some SCADA system components, many do not have logging capabilities. The cost of installing, operating, and maintaining extensive auditing a...

For reasons of efficiency, maintence, and economics, data acquisition and control platforms have migrated from isolated in-plant netwoeks using proprietary protocols, and the internet. The downside of this transition has been to expose SCADA systems to the same vulnerabilities and threats that plague Windows-based PCs and their associated networks. Some typical attacks that might be mounted against SCADA systems that employ standard hardware and software are listed here: Image Saurce: gcn.com - Malicious code such as viruses, trojan horses, and worms - Unauthorized disclosure of critical data - Unauthorized modification and manipulation of critical data - Denial of service -  Unauthorized access to audit logs and modification of audit logs Terminology of PLCs The L3GD203-Axis Gyro Introduction To Robotics Classification Of Robotics SCADA System Architecture   Most SCADA system, paticularly the local PLCs or controllers, have ro operate in real-time or near re...

Specific terminology is associated with the components of SCADA systems. These SCADA elements are defined as follows: - Operator : Human operator who monitors the SCADA system and performs supervisory control functions for the remote plant operations - Human machine interface (HMI) : Presents data to the operator and provides for control inputs in avariety of formats, including graphics, schematics, windows, pull-down menus, touch-screens, and so on. - Master terminal unit (MTU) : Equivalent to a master unit in a master/ slave architecture. The MTU presents data to the operator through the HMI, gathers data from the distant site, and transmits control signals to the remote site. The transmission rate of data between th MTU and the remote site is relatively low and the control method is usually open loop because of possible time delays or data flow interruptions - Communications means : communication method between the MTU and remote controllers. Communication can be through th...

Most SCADA half-duplex protocols do not allow one slave station to talk to another slave station, exept throught special application-soecific  code, which requires processing overhead in the master station. However, Allan-Bradleys DF1 half -duplex protocol implements slave-to-slave communications as a feature of the protocol within the master station, wirhout any additional application code or extra procesing overhead. Refer to chapter 3 of the DF1 Protocol and Commond Set Reference Manual, pulication 1770-RM516, for additional information. If one slave station has a message to send to another, it simply includes the destination slave station's address in the message instrucrion's destination field in place of the master station's address when responding to a poll. The master starion checks the destination station address in every packet header it receives from any slave station. If the address does nt match its own station address, the entire message is forwarded back on...

From the introduction of actuators and transducers (that made monitoring of processes easier, more accurate and less costly) at the instrumentation level to the introduction of open standards (to improve the interchange of data between a SCADA sysem and other processes within an organisation), SCADA systems have exploited the various technological advances to drive forward their proficiency. The drive of modern SCADA systems is to: Provide instrumentation and Rus/PLCs for asset or process solutions that can be easily managed and to provide operational benefits from the SCADA host down to the instumentation, not just in terms of controlling and retriecing data but also engineering, implementing, operating and maintaining these assets. Develo and employ open standards to duther ease the integration of assets within a SCADA system using best practices defined by open groups and not a single manufacturing entily. This will in turn reduce the cosr of owning SCADA. Provide secure envir...

 Security for SCADA systems has in recent years become animportant and hotly debated topic. Traditionally SCADA systems were isolated entities that were the relm of operators enginners and technicians. Ths has meant that SCADA Host platforms were not necessarily developed to have protected connections to public networks. This left many SCADA host platforms open to attack as they did not have the toos necessary to protect themselves. In terms of remote assets communicating back to a SCADA Host, security has been an issue for many years with numerous documented attacks on SCADA systems. However, it's only been in recent years that an open standard has been produced to provide secure encrypted and authenticated data exchanges between remote assets and a SCADA Host platform. Conclusion of SCADA   About Slave-to- Slave Messaging SCADA Programmable Logic Controllers (PLCs) Terminology of PLCs   The L3GD203-Axis Gyro Solutions for remote asset and SCADA host communic...

Traditionally, SCADA Host software has been the mechanism to view graphical displays alarms and trends. Control from the SCADA Host itself only became available when control elements for remote instruments were developed. These systems were isolated fro the outside world and were the domain of operaors, technicians and engineers. Their responsibility was to monitor, maintain and engineer processes and SCADA elements. With advancements in Ingormation Tecnology (IT) this is no longer the case. Many different stake holdes now require real time access to the data that the SCADA Host software generates. Accounting, maintenance management and material purchaasing requirements are preformed or party preformed from data derived from the SCADA system. SCADA Systems SCADA Field INstrumentation PLCs and RTUs Remote Communications Networks Consequently, there is a drive for the SCADA Host to be an Enterprise entity providing data to a number of different users and processes. This has encora...

The remote commuication network is necessary to relay data from remote RTU/PPLCs, which are out in the field or along the pipeline, to the SCADA host located at the field office or central control center. With assets distributed over a large geographical area, communicaton is the glue or the linking part of a SCADA system and essential to its operation. How well a SCADA system can manage communication to remote assets is fundamental to how sucessful the SCADA system is. Twnty years ago the comunication network would have been leased lines or dial-up modems which were very expenive to install and maintain, but in the last 10-15 years many users have switched to radio or satellite communications to reduce costs and eliminate the problematic cabling issues. More recenly, other communication tyes have been made available that include cellular communictions and improved radio devices that can support greater communication rates and better diagnosics. However, the fact hat these types of c...

Programmable Lagic Controllers (PLCs) and Remote Telemetry Units (RTUs) used to be distincly different devices but over they time they are now almost the same. This has been a convergence of tecnology as manufactures of these devices exlanded their capabilities to meet market demands. If we go back 30 years, an RTU was a 'dumb' telemety box for connecting field instruments. The RTU would 'relay' the data from the instruments to SCADA host without any processing or control bud had well-developed communication interfaces or telemetry. In the 1990s control programming was added to the RTU so it operated more like a PLC. PLCs on the other hand could always do the conteol program but lacked communication interfaces and data logging capability, which has been added to some extent over the past decade.  SCADA Systems SCADA Field INstrumentation PLCs and RTUs Remote Communications Networks SCADA Host Sofware A futher development of devices in the field is to of...

"You can't control what you don't measure" is an old adage, meaning that instrumentation is a key component of a safe and optimised control system. Traditionally, pumps and their coresponding operational values would have been manually controlled i.e an operator would start/stop pumps locally and valves would have been opened.closed by hand. Slowly over time, these instruments would have been fitted with feedback sensors, such as limit switches, providing connectivity for these wired devices into a local PLC or RTU, to relay data to the SCADA host software PLCs and RTUs Remote Communications Networks SCADA Host Sofware SCADA Security Conclusion of SCADA Progress of instrumentation Although today's instrumentation technician rewuires more technical knowlwdge and the ability to design, install and maintain equipment, that in the past, this is mitigated by the reduced cost in automating processes and higher technical skills held by personnel. Today, most...

The definition of SCADA is ‘Supervisory ontrol and Data Acquisition’. The major fungcion of SCADA is for acquiring data from remote devices such as valves, pumps, transmitters etc. and providing overall control remotely from a SCADA Host software platform. This provides process control locally so that these devices turn on and off at the right time, supporting your control strategy and a remote method of capturing data and events (alarms) for monitoring these processes. SCADA Host platform also provide functions for graphical displays, alarming, trending and historical storage of data. SCADA Field INstrumentation PLCs and RTUs Remote Communications Networks SCADA Host Sofware SCADA Security Historically, SCADA products have been produced that are generic with a ‘one shoe fits all’ approach to various markets. As SCADA has matured to provide specific solutions to specific SCADA markets it has provided solutions for ide area network SCADA systems that rely on tenuous co...