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Human Machine Interface. An industrial automation term describing a graphical interface into the process. Usually a PC application that uses tags from a PLC or DCS. At one time this was called MMI (Man Machine Interface) until engineering geeks became politically correct.
The operator of the machine was so stoned he didn't see all the alarms on the HMI while the entire lot was scrapped.
by bagadonutz November 06, 2005