Siemens SIMATIC NET PROFIBUS manual Illumination Range

6ZB5530–3AC30–0BA1 Infrared Link Modul (ILM)

11.1Illumination Range

To determine the arrangement of two PROFIBUS ILMs on an infrared transmission link, the illumination range of the sending PROFIBUS ILM must be known. The receive cone is broader so that with the half-duplex transmission used with PROFIBUS the restriction results from the narrower cone.

Note

Each PROFIBUS ILM on an infrared link must be arranged and aligned so that it reaches its partner with its transmit cone.

The illumination range of the sender is shown in Figure 19. In the range from 0.5 to 12 m, there is adequate illumination density in a solid angle of )/– 10 degrees with free emission without shadows caused by obstacles. At 12 m distance from the sending PROFIBUS ILM, there is an illuminated circular area with a diameter of approximately 4 m. Although the send window of the PROFIBUS ILM is neither round nor square, from a distance of 2 m the illuminated area is practically round since from this distance the light source can be assumed to be a point.

At a distance greater than 12 m, in the same way as the illumination provided by a spotlight, the illuminated area starts to reduce. At 15 m distance, an illuminated area of 2 m diameter is guaranteed.

Note

These data are only guaranteed when the windows of the PROFIBUS ILM are clean. From time to time, the window should be cleaned using a clean soft cloth as usual with other optical devices or glasses. Under no circumstances should aggressive or abrasive cleaning agents be used.

Condensation on the window or wetting with water or other liquids reduces the illumination range. With condensation, a reduction of approximately half of the maximum range has been measured. If the liquid produces bubbles, the reduction is sometimes even higher since not only the optical attenuation but also the optical refraction of the liquid takes effect.

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