SCADA systems

SCADA systems:

SCADA systems consists of SCADA Master which is generally referred as SCADA Master Station which includes SCADA hardware system and SCADA software system and Remote Terminal Unit (RTU). SCADA master station job is to communicates with  Remote Terminal Unit (RTU) for carrying out monitoring, control, data storage and Human Machine Interface (HMI) operations. SCADA hardware consists of hardware components such as very reliable PC ( work station ) and its peripherals present in the master station and able to control the RTUs or PLCs (programmable Logic Controllers) through SCADA software. SCADA software system was developed to communicate with the PLCs or RTUs for data acquisition and control operations.

SCADA Master System:

SCADA Master Station has the centralized control to monitor and control the remote stations. SCADA master station should perform tasks such as:

• Display the real time data received from PLCs, RTUs, and IEDs
• Stores the received historical data received
• Activates alarms when necessary
• Displaces sequences of events during disturbance
• Provide an Human or Operator Interface for supervisory control
• Perform the communication control over the network

SCADA Hardware system:

Master station is a part of the WAN or LAN network. The hardware for the master station includes high end and more reliable PC (workstation), its peripherals and its communication ports. Reliability of the hardware in master station is important else entire SCADA system will tamper. Redundant workstations are provided to improve the reliability of the system.

SCADA software System:

SCADA software systems consists of

1.The operating system software:

program on which SCADA software programs runs

2.SCADA system software:

SCADA system software includes 4 modules

Data acquisition: Refers to receiving and analyzing and processing the data from the field. 

Control: Controlling the remote units (RTUs) by commands initiated either by operator or automatic according to predefined parameters. 

Data Storage: Storing the historical data obtained from the field. 

Human machine Interface: Includes input and output devices for interaction between the operator and software, the way the data is displayed in graphs and the commands given to the system

3.SCADA application software:

SCADA application software is optional software to enhance the performance of the SCADA main software

eg: software tools for analyzing the system disturbance recordings

Remote Terminal Units (RTU):

Remote Terminal Units employed at remote units o network and it acts as interface between the SCADA master system and field instruments. It receives and stores all the information from field such as values, alarms, meter readings in the memory. When master station asks the data it transmits the data to master station. Based on the commands received from master station it performs certain tasks such as opening value, tripping the relay