SCADA stands for Supervisory Control and Data Acquisition. Also some authors define it as the technology that enables data collection remote locations, as well as sending information to these locations.
Scada allows to omit the need for operators in these remote locations, which will now be known as remote stations. In this chapter we present some processes that are benefited with the installation of a SCADA system and publicize the basic elements of the system.
A SCADA system allows an operator at a central station located at great distances from the location of industrial processes, can make adjustments or changes in the local controllers of the process. Such is the case of opening or closing valves at a distance, knowing the state of safety switches a system to monitor the alarm status of the process and obtain information on the process variables involved.
When the distance of the process becomes very large: hundreds or thousands of miles from one point to another, the benefits in reducing the cost of routine visits can be appreciated. The value of these benefits are increased if the area to visit is very accessible. Programs and, if necessary, additional hardware is needed, it is called, in general, the SCADA system.
A SCADA must meet several goals for your facility is fully exploited:
Must be open architecture systems that can grow or adapt according to changing business needs.
Must communicate with ease and transparently to the user with plant equipment and the rest of the company (local and network management).
Must be easy to install programs without excessive hardware requirements and easy to use with user friendly interfaces.
Fig.1 monitoring and water pumping to a local station
This application has three tanks collectors mts3 1 000 each. From a pumping station located 20 miles is pumped to a reservoir which has an elevation higher than 1000 ft. The water reaches the treatment plant by gravity. As you can see, the monitoring station is located at more than 50 miles of the tanks collectors, but the information on the levels of these tanks is displayed in "real time", ie the level variables are updated times very small, less than 1 second.
From the monitoring station can be switched on and off the pumps that feed water to the reservoir manually and automatically. When working in manual mode, the operator control station pumps turning lights on signal from the panel.
When operated automatically, the local controller monitors the level of the reservoir and when it detects a minimum, turn sends the feed pumps to achieve the desired level.
Figure 2 Monitoring and control of oil platforms
The SCADA system allows control of the pumping stations, monitoring the levels of storage tanks at the refinery and monitoring and control of the tanks in the area of study. All operations are monitored from two local stations that operate on Unix platform.
SCADA SYSTEMS CLASSIFICATION
SCADA systems are characterized by great diversity, depending on the process they control, technology used, geographic location, etc.. Below groups Scada systems as their geographical distribution, as these systems share certain characteristics in common from this point of view.
General descriptions of hardware and basic software used in each system are valid general found major differences in the application software that adapts to each case.
a) LINEAR SYSTEMS
Systems with linear development
Oil.
Gas.
Pipelines.
Aqueduct.
rail and underground networks.
distribution networks of electricity.
b) BRANCHED SYSTEMS
In this case the system covers a large area:
Reservoir.
gas distribution networks, water or electricity.
The systems associated with these processes that rely significantly on their individual characteristics.
