Difference between RTU & PLC / SCADA & HMI

[Heartnet 0]

Hi, Can someone please clarify whats the difference between RTU (remote terminal unit) and PLC (programmable logic controller)? As well as HMI & SCADA? I am so confused. Isn't RTU basically PLC? Thanks.

[RussB 22]

What book did you read, maybe you need to read it again? What did it say that confused you? I really don't believe it will help you much if I do your homework for you. :) Edited 11 Mar 2013 by RussB

[Heartnet 0]

Book says SCADA consist of a HMI, RTU and a PLC. For what I understand is that. RTU = PLC. Why doesn't the book categorise them both into one?

[Heartnet 0]

A book that I read states that SCADA consist of a HMI, PLC and RTU. Can SCADA exist if a system only consist of HMI and PLC? Can PLC act like RTU?

[RussB 22]

What is a SCADA, the acronym stands for Supervisory Control And Data Acquisition. Do those devices meet all of this? If no, why? If yes, how? What does your book say about that?

[Heartnet 0]

From what I can gather Local SCADA consist of a human machine interface, programmable logic controller Wide range SCADA consist of a human machine interface, RTU. -> remote terminal unit. RTU act like a PLC but it provide better communication ie: thru Ethernet and etc. Am I on the right track here.