Sun Tracking Routing Entry
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Sun Tracking Routing Entry |
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A sun-tracking routing entry allows the router to send up to 16 different scenes to a group of devices depending on:
the calculated position of the sun at a specific location; and
the actual amount of light detected by the interior- or exterior-mounted light sensors.
In the current version of Designer, you can use sun tracking routing entries to adjust the position of the blinds incorporated into the lighting system. You can do this directly, with scene control, when a Helvar 490 Blinds Controller is used. In addition, a selection of manufacturer-specific blind motors are supported on the DMX port of a 920 Imagine router. In this case, you need to use the sun tracking routing entry in combination with a Blinds Control Routing Entry.
This Help topic describes the rationale that underlines a sun-tracking routing entry. It is structured as follows:
Calculated position of the sun describes how you can take advantage of the sun’s apparent motion during the year to control a group of devices.
Information from the sensors describes how this information can be used when something blocks the path of the sunlight.
For information about how to create a sun tracking routing entry, see Create a Tracking Routing Entry.
The path of the sun varies every day of the year because of the Earth’s tilt and orbit. However, the exact position of the sun at any given moment can be easily calculated from the geographic coordinates, the time zone and the date and time of the observer.
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Path
of the sun during the year
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For simplification, the following subsections give a horizontal view and a vertical view of how a sun tracking routing entry can take advantage of the calculated position of the sun to set the scene that is most relevant for your purpose.
Your window has a field of view that depends on its dimensions, its azimuth, and the location of the observer. The following figure shows this for a window facing South.
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Pathway of the sun – Horizontal view
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For windows or groups of windows facing different directions, you would normally create a sun tracking routing entry per building face.
The sun elevation plays a significant role in the illuminance of any area. For example, in many latitudes, the summer sun is so high during the middle hours of the day that it is not necessary to pull the blinds far down. However in winter, when the sun travels a lower path through the sky, it may be important to shut them in order to prevent visual discomfort.
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Pathway of the sun – Vertical view for
35° N (Algeria, Tibet, Honshū, Tennessee; hour lines are
shown in solar time.
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The data of the calculated position of the sun (see Calculated position of the sun) is enough for the router to recall the appropriate scene as long as nothing stands in the way of the light. If something blocks the light, for example when the sky is covered by cloud, you can take advantage of the information from the light sensors to configure how the router system is to react.
To do this, you need to define Conditions that enable the system to take a specific sun-tracking action when the readings from these sensors are above or below a specified value over a certain period of time. The choice of this period of time is key to preventing your device from continually reacting to changes in light level while being fast enough to accomplish the required task.
The following figure illustrates how the various data sources can be combined to create a sun tracking routing entry.
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Sun tracking – Data sources
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