SCADA provides a complete pictorial overview of the entire plant process with necessary monitoring and control facilities at a central location The control systems are always coupled with Man Machine Interface (MMI) or Supervisory Control and Data Acquisition Software SCADA software is to be connected to PLC / PID / DCS systems which in turn are connected to field instruments
Previously without SCADA software, an industrial process was entirely controlled by PLC, CNC , PID & micro controllers having programmed in certain languages or codes. These codes were either written in assembly language or relay logic without any true animation that would explain the process running. It is always easy to understand the status of the process if it is shown with some animations rather than written codes.
It works like a supervisor who supervises the entire plant area, it also controls the process as well as it converts the data segments for storing process values i.e. level, pressure, switch positions, density, temperature, messages, etc From a distant place if we want to run the process i.e. starting , stopping , opening and closing of field instruments, resetting alarms, as well as logging the various values; SCADA can help…
Dynamic process graphic Real-time and Historical trending Alarms Recipe Management Security Device connectivity Script for logic development Database connectivity Networking
Using this feature, one can develop graphics which can resemble the plant. The graphics can include reactors, valves, pumps, agitators, conveyors as well as other equipment and machinery used in the plant. The status of the equipment running/stopped can be shown using different colors/animation. Typicallythe SCADA software will have many ready to use symbols for proper representation which can be used in any type of industry.
This facility is used for representing the data in graphical form Real-time data will plot the real-time value for fixed period of time while historical data will have historical data stored value which can be viewed on demand Depending upon the storing capacity of the hard- disk one can specify the no of days the data can be stored
Every plant needs proper monitoring and control of the process parameters Alarms represent warnings of process conditions that could cause problems, and require an operator response Generally alarms are implemented by using the lamps or hooters in field but in SCADA it can be represented using animation. In many SCADA software, four type of alarm limits are used ie HI, HIHI, LOW, LOW LOW
In many cases we use the same plant for manufacturing different product range. For example an oil blending plant can manufacture power oil, transformer oil, automobile oil. The recipe management is facility used for maintain various recipes of different products and implement it on the process The recipe can be stored in a single server and it can be fetched by any client server from any area to run the process
Every SCADA software has various levels of security for securing the application by avoiding unauthorized access Depending upon the access level given the operator/engineers is allowed to do the task. In most of the cases, operators are allowed only to operate the plant while maintenance engineers can do the application modifications The security can be given for individual as well as for groups
Every control hardware has its own communication protocol for communicating with different hardware/software. Some of the leading communication protocol include Modbus, Profibus, Ethernet, Dh+, DH485, Devicenet, Controlnet. The SCADA software needs device driver software for communication with PLC or other control hardware. More the driver software available better is the device connectivity. Most of the SCADA software used in the industry have connectivity with most of the leading control system.
In many plants, it is important to download the real- time information to the MIS. In this case the database connectivity is must. Many SCADA software don’t have their own database. Hence for storage and reporting they use third party database like MS Access or SQL
Script is a way of writing logic in SCADA software. Every SCADA software has its own instructions and way of writing program. Using scripts, one can develop complex applications. You can create your own functions to suit the process requirement and execution. Various types of scripts make project execution simpler for programmer.
In many applications, we have to use more than one SCADA software/operator stations. This can be achieved by taking the SCADA node on network. In many cases Ethernet TCP/IP is commonly used for networking. In certain cases the SCADA software use proprietary networking protocols for networking.
To start with the SCADA software were used for monitor and controlling the parameters locally.
Subsequently the modems were used to monitor the data over a distance
The latest advancement in the SCADA technology includes the data monitoring on wide area network using modems, Ethernet tcp/ip as well as GPS system
Wonderware : InTouch Intellution : iFix (Earlier Fix DMACS) Allen Bradley : RS View (Earlier Control View) Siemens : WinCC (Earlier Coros LS /B ) GE Fanuc : Cimplicity Indusoft : I W S Movicon : Progea