Wattstopper LMLS-500 Open Loop Multiple Zone DLM photosensorWattstopper LMLS 500 LMLS 500 Product Description The LMLS 500 is an open loop, multi zone photosensor that measures the daylight contribution in order to automatically switch or dim up to three zones of lighting. It is part of a Digital Lighting Management (DLM) system and sends light level signals to control loads connected to DLM on off or dimming room controllers. Specifications: Product Line: Wattstopper UPC Number: 754182928927 Product Width: 3.