hmi and scada

hello, what is the difference and similarities between HMI and SCADA

http://lmgtfy.com/?q=SCADA+wiki <- some info on SCADAs

http://lmgtfy.com/?q=HMI+wiki <- some info on HMIs

Search the forums and google a bit. With a little knowledge you can come back and ask specific questions.

HMI is a generic term - Human Machine Interface. A SCADA system is a HMI, so is a touch screen.

The way I view it...

HMI (or MMI) Human Machine Interface (or man machine interface), these are anything that will interact with your PLC from an human interaction, so if someone is changing the sp on a temp and they are using a (Red Lion or Panel View or etc) this would be an HMI.

SCADA (Supervisory Control and Data Acquisition) is more of a machine control and does not have to interact with a PLC, a lot of chemical companies use systems like this along with PLC they can be faster at controlling many PID loops they can have there own logic and run systems (not that a Red Lion can't)

This is the way I look at them... but I may be looking to deep

Still a HMI in my view. I use Citect all the time but the interfaces are not very sophisticated - pretty pictures - trend data - raise alarms - write some info to the PLCs - an occasional genie or super genie - that is about all. No processing involved - do use a Disk PLC from time to time though to collect and manipulate data.