The type of controller can be selected based on customer specification, as well as present and future requirements. The control system is typically located in an approved electrical panel which is positioned in close proximity to the system that is being controlled. As an alternate arrangement, the controller could be located in a room designated specifically for controls. In either situation, all wiring to and from the controller is always carefully marked with an identifier, correlated to the supplied working drawings. Operator interface control stations are located in strategic positions along the route of the conveyor, containing the essential operating controls for the system. Duplicate controls can be located at the system control panel either by mounting parallel buttons or by providing a Man Machine Interface panel (MMI) directly on the panel door. Parallel buttons provide a simple, cost effective solution, whereas the MMI terminal provides direct control over the system and real time status of both the system and its sub-components.