DCS
DCS systems have for many years provided multi-disciplined controllers for logic, sequential and process control, HMIs, custom applications, and business integration on one platform.
PLC
Although PLCs have become more powerful, they are still based on “loose” component architectures allowing functions to be easily added with hardware and software. For example, a historian may be added to many PLC products by plugging a module into the backplane that acquires data from the controllers, but history communications is done over a separate Ethernet connection.
