SCADA

SCADA  Supervisory  Control  And  Data  Acquisition.

What is SCADA?

SCADA (supervisory control and data acquisition) is a category of software application program for process control, the gathering of data in real time from remote locations in order to control equipment and conditions. SCADA is used in power plants as well as in oil and gas refining, telecommunications, transportation, and water and waste control.

SCADA systems include hardware and software components. The hardware gathers and feeds data into a computer that has SCADA software installed. The computer then processes this data and presents it in a timely manner. SCADA also records and logs all events into a file stored on a hard disk or sends them to a printer. SCADA warns when conditions become hazardous by sounding alarms.                                                                                                           

SCADA systems were initially employed in the 1960s. They include both software and hardware components. The hardware collects and enters data into a computer with SCADA software. 

SCADA systems consist of:

• Field data interface equipment, generally programmable logic controllers (PLCs) or remote terminal units (RTUs). These connect to field sensing devices, local control switchboxes and valve actuators. Field-data-interface equipment forms the core part of SCADA systems.

• A communications system. This is employed to move data between different pieces of field data interface equipment and control units, and the computer systems employed in the SCADA central host. The system may be telephone, radio, satellite, cable, and so on, or a combination of any of these. The communications network is designed to offer the way by which the data can be transmitted in between the field-based RTUs and the central host computer servers.

• A central host computer server(s). This is often known as a master station, a SCADA center, or a master terminal unit (MTU). The central host computer is usually a single computer or a computer server network.

• A set of standard and/or customized software systems. They are helpful in delivering the operator terminal application and SCADA central host. This supports the communications system, and monitors and controls the remotely located field-data-interface equipment.

As such it is a software package that is purely positioned on top of hardware to which it is interfaced, in general via Programmable Logic Controllers (PLC), or other commercial hardware modules. 

SCADA systems are used not only in most industrial part processes: for example, steel making, power generation (conventional and nuclear) and distribution, chemistry, 

but also in some experimental facilities such as nuclear fusion. 

Main functions of the system SCADA

· Remote Monitoring Facilities 

· Remote Control Facilities 

· Information Processing 

· Presentation of Dynamic Graphics 

· Report Generation 

· Presentation of Alarms 

· Storage of Historical Information 

· Introducing Trend Charts 

· Schedule of Events

In conclusion a SCADA system is able to record data, generate alarms and manage a distributed control system through a network of hardware (usually PLCs and PACs).

CAN Communication Protocol

CAN Comunicatio Prococol

CAN or CAN Bus, is short for Controller Area Network is a bus serial communications for control applications in real time, with a communication speed of up to 1 Mbit per second, and has excellent detection and fault isolation . That is, this is the best and most current technology in new vehicles. 

This system uses two cables in which two signals traveling exactly the same amplitude and frequency but completely reverse voltage modules in these two pulses identifies the message, but also has options to keep active network but fails one of the communication cables.

Esquema simplificado de un Bus CAN

CAN is a durable and economical network that allows multiple devices to communicate with each other. One benefit is that it allows the electronic control units (ECUs) have a single CAN interface (as pictured), instead of different analog and digital for each device in the system inputs. This reduces the cost and weight in cars.

The main advantage of this protocol is that it allows sharing of a large amount of information between the control units in the system, which causes a significant reduction in both the number of sensors used and the number of cables that make up the electrical system, important topic considering the dimensions that are handled within a car. Thus, significantly increase the functions present in automotive systems where CAN-BUS is used without increasing costs. 

Security systems incorporating the Can-Bus allows the probability of failure in the communication process are very low, but it remains possible that cables, contacts and control units themselves present some dysfunction.