SCADA
SCADA stands for Supervisory Control and Data Acquisition. It describes the control system of an industry and is really a computer system which controls and monitors a certain process. The process may be infrastructural, facility or industrial.
- Industrial processes – these include production, refining, manufacturing, power generation and fabrication. Activities performed by the system include inventory management and quality control. Processes may be carried out in batch, discrete, repetitive or continuous modes. The system is used to control refrigeration, lighting and entry units.
- Infrastructure processes – these include water treatment as well as distribution, collection and treatment of waste water, distribution and transmission of electricity. It also refers to large communications processes, civil defense siren systems, gas and oil pipelines. These can be either public or private.
- Facility processes – Both public and private facilities have all the facility processes. These are space stations, airports and ships. Transportation companies use the system to monitor the supply of electricity, control traffic signals for rail systems, to locate and track trains and buses and to control the crossing gates at railroads.
SCADA gathers data from several sensors and then transmit the data to a central computer which stores the data. The main advantage of using a SCADA system is its ability to monitor processes in real time.
The term SCADA refers to one central area which includes the following:
- Signal hardware (both input and output)
- Controllers
- Networks
- User interface
- Communications equipment and software
Four important functions carried out by a SCADA system are.
- Gathers data
- Transmits data
- Presents data
- Controls processes
The most important functions of the SCADA system are carried out through the Remote Terminal Units (RTU) which is made up of a logic converter that is set to certain standards. SCADA systems are viewed as highly intellectual and they are capable of operating with little or no human intervention.
The system has many data elements known as points. Each point is a monitor or sensor, and they are categorized as either hard point or soft point. A hard point can be a monitor while a soft point may be an application. Data from both hard and soft points are recorded and stored.
A SCADA system has a user interface that is called Human Machine Interface (HMI). This is where the data is presented to the human user. It is equipped with controls to enable the user to interface with the system.
SCADA systems are suitable for running and monitoring processes; from small processes such as climate control to large processes such as controlling a nuclear power plant. They are suitable for use where human control would be impractical. The main advantages of the system are:
- Improve the quality of products.
- Reduces operational and maintenance costs as fewer personnel are required to carry out tasks.
- Can be easily integrated into the business.
- Preserves capital investment.
The initial cost of installing a SCADA system may be high but the long-term benefits far outweigh the costs. The use of the system will result in greater efficiency levels which, in turn, should positively impact business profitability.