OI (redirected from Oy)

(Operator Interface) A low-level graphical interface to a specialized computer (DCS, PLC or PAC) on the plant floor. Typically built into a ruggedized terminal for shop floor use, it provides a remote interface to the push buttons, switches and gauges found on the equipment itself. An OI does not offer the rich graphics and flexibility of a Windows-based interface. Contrast with HMI.

In the Plant

This operator interface is mounted right into the wall of a packaging plant. Although colorful, it does not have the rich graphics of a human machine interface (HMI). (Image courtesy of Opto 22, www.opto22.com)