What makes SCADA and DCS different? Does every DCS have SCADA? If yes then how are they intergrated?

 

Speaking in gross generalities:

Although SCADA can execute control commands remotely, SCADA is generally more about the historian: data collection of process data, alarms and events from various and multiple devices and locations, archiving that data, and providing means of analyzing the data.

A DCS is primarily about control. The historian part is always optional (at big money) but I suspect that the DCS without an historian is a rare beast.

Integration between the various components - controllers, HMI, historian - of a DCS is very tight which is part of the price tag of a DCS.

SCADA achieves integration as a result of lots of man hours 'integrating' all the bits and pieces.

 

Speaking in gross generalities:

Although SCADA can execute control commands remotely, SCADA is generally more about the historian: data collection of process data, alarms and events from various and multiple devices and locations, archiving that data, and providing means of analyzing the data.

A DCS is primarily about control. The historian part is always optional (at big money) but I suspect that the DCS without an historian is a rare beast.

Integration between the various components - controllers, HMI, historian - of a DCS is very tight which is part of the price tag of a DCS.

SCADA achieves integration as a result of lots of man hours 'integrating' all the bits and pieces.

so where there is DCS, SCADA is must there too? right?

 

Yes, the features of SCADA, Data acquisition and an historian, are present when a DCS has an historian,

 

Yes, the features of SCADA, Data acquisition and an historian, are present when a DCS has an historian,

that was very helpful
thanks !

 

A DCS will be for acquisition, processing and control response of systems. SCADA is generally for data transmission and historian. As an example, ABB's DCS INFI-90 open, Harmony, and Symphony have trends that can function as a historian, but its main function is to respond to process inputs. The DCS's historian can have certain limitations with retention of data and acquisition of stored data by supervisory personnel (managers etc.)
This is where SCADA is useful, OSI Soft with their PI system allows the powers that be to look at the tags of concern and has the architecture to create trends, and graphs that are written at more precise intervals. The interface can be more user friendly for the type of data viewing that is necessary for the communication of plant efficiency, material usage, and equipment degradation.
Utilizing SCADA in this fashion can provide better network security as well. The DCS can be firewalled to the SCADA computer/server, and then the SCADA should have its own firewall. This puts more hurdles for anyone trying to access plant control for nefarious purposes.
This link has more information and videos to expound on the things discussed here. https://www.dpstele.com/blog/similarities-and-differences-between-scada-and-dcs.php