Control system is plant brain so make us sure, all parameters are under control accurately and production is done as well as we expected. Control methods are so different with large variety.
The most famous control system is PLC so can receive some input with different specifications and take the best possible decision as per philosophies of control and built in logic program. It has a simple structure and so suitable for small and middle applications but when we faced to many I/O in a plant we need more powerful device can manage a huge data also we will have to use DCS (Distributed Control System) and in some cases another system for emergency actions is considered for more safety knows as ESD (Emergency Shut Down System).
Control system should be designed based on plant requirement and many factors such as I/O quantity, redundancy, cycle times, scan rates and measuring devices and control points dispersion at site.
Control system contains some local equipment rooms (LER) so control an area and connected to a central control room (CCR). All devices can manage, adjust and repair from LERs or CCR remotely and operators can access to the devices well.
There are some engineering and monitoring stations in a DCS so provide data logging and online control and monitoring capabilities for operators. It depends on system arrangement and architecture and user requirements.
There are some connections in to the other subsystems such as packages and utilities control stations too, could help us to have a high speed or Ethernet gate for data transfer to other places and users. In new cases there is a possibility to transfer and storage system data to a clouds and be sure that will be remained for long time.
Much different type of communications such as conventional, Profibus, Foundation Field bus and etc can be used in a control system.
We can provide the best control solutions for your plant you just know your requirements.