The Operator Interface Panel (OIP) provides the operator interface to the controller. This interface comprises a 2 line by 20 character, backlit, LCD alphanumeric display, a 20 key membrane keypad, with two indicator leds.

The OIP handles display and data entry, relieving the main processor of display refresh and key scanning functions.

The OIP communicates with the main board using the OIP communications channel, RS485 at 38400 baud. Refer to section 8 for details of the communications protocol.

Up to three OIPs may be connected to the controller, using addresses 1, 2, and 3. These panels operate completely independantly.