Cabling Distances And Power Requirements; Mounting; Selecting The Location For The Camera - Videotec MDI Manuel D'instructions

5.4.1 Cabling distances and power requirements

The MDI dome will function with a supply voltage within the range 12-24V
supply voltage is not critical. Ensure that the power source and associated cabling is capable of continuously
supplying 4VA and peaks of 6VA.
If the cabling distance is greater than 150 metres, it is advised that the camera be powered locally from either a
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24V~ or 12V supply. This is best achieved by connecting the supplied pigtail cable to the second RJ-45
connector that is labelled "CHAIN" and using the DC input power jack to complete the local power connection.
When connected in this manner, it is important that no power be supplied via the fixed CAT-5 cabling that is
connected to the RJ-45 connector labelled "CONTROLLER".

6 Mounting

This product is supplied complete with mounting hardware that is intended to be used for surface mounting the
dome on internal ceilings constructed from plaster board, timber, concrete or similar materials.
Additional brackets are available to enable the product to be pendant and wall mounted. Please contact your
supplier for the appropriate brackets if contemplating mounting the product in such a manner.
The following procedure describes the process for mounting the dome in a typical ceiling installation. Actual
requirements may vary depending on the material and structure of the mounting surface.

6.1 Selecting the location for the camera

This product is designed for indoor use only and it must not be installed where exposed to rain or moisture
and extreme temperature variations.
Carefully select the mounting location to ensure that it provides the optimal field of view of the intended
surveillance area. Care should be exercised to ensure that the field of view is not blocked, wholly or in-part by
immovable objects. The mounting location should ensure that the product is safe from exposure to moisture,
high temperatures and/or direct sunlight and is also free from vibrations.
The most important consideration when selecting the location of a camera is the desired result on the monitor.
For example, if the purpose of the system is to clearly identify human subjects, the camera should be positioned
so that viewed subjects occupy at least 50% of the viewed screen height.
Table 5 illustrates the percentage of a monitor's height that will be occupied by a 1.6 metre tall person standing
at various distances from the camera for the two dome models. This table is based on the camera being
mounted on a 3 metre high ceiling.
If a specific object or region of interest is to be observed, without the need to constantly reposition the camera, it
is important to site the camera so that the object or region of interest fits within the camera's field of view. As an
aid, Table 6 indicates the displayed field of view for the two lenses at various distances from the camera.
Supply voltage
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12V
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24V o 24V~
Table 4 - Maximum cable lengths for CAT-5 cable.
Object distance
Standard lens
(metres)
2
4
6
8
10
12
14
Table 5 - Subject screen height and viewing distance
Pag. 8
Maximum cable length
25 metres
150 metres
Wide lens 6mm
8mm
239% 178%
120% 89%
80% 59%
60% 44%
48% 35%
40% 30%
34% 25%
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or 12-24V~. The polarity of the
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