Pelco C600M-B Manuale Utente
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Pelco Manual C600M-B (4/00)
Prior to installation and use of this product, the following WARNINGS should be observed.
1. Installation and servicing should only be done by qualified service personnel and conform to all local
codes.
2. Unless the unit is specifically marked as a NEMA Type 3, 3R, 3S, 4, 4X ,6 or 6P enclosure, it is de-
signed for indoor use only and it must not be installed where exposed to rain and moisture.
3. Only use replacement parts recommended by Pelco.
IMPORTANT SAFEGUARDS AND WARNINGS
DESCRIPTION
The GIT100 Ground Loop Isolation Transformer reduces interference with CCTV signals caused by
ground loop potentials.
ground loop potentials.
A ground loop is an electrical problem that happens when an AC current interferes with the ground refer-
ence level of the video signal. It occurs on the conductive path formed by the shield of the coaxial video
cable and the chassis of the video equipment. A loop results from the difference between the voltage po-
tential of the shield at one end of the cable, versus the voltage potential of the shield at the other end.
ence level of the video signal. It occurs on the conductive path formed by the shield of the coaxial video
cable and the chassis of the video equipment. A loop results from the difference between the voltage po-
tential of the shield at one end of the cable, versus the voltage potential of the shield at the other end.
The electrical level of the shield is usually zero volts. When a ground loop is present, this level fluctuates
above and below zero volts. The greater the difference, the more severe the video distortion or tearing.
If the potential is too great, it can destroy the equipment.
above and below zero volts. The greater the difference, the more severe the video distortion or tearing.
If the potential is too great, it can destroy the equipment.
Larger voltages are common for distances of a few thousand feet, not for small separations. Potentials of
greater than 0.5 are commonly found between two points in the same building.
greater than 0.5 are commonly found between two points in the same building.
INSTALLATION
For best results place the transformer near the monitor. Refer to Figure 1.
The shorter the coaxial cable the greater the performance of the GIT100. Use more than one ground loop
isolation transformer when the ground loop potential exceeds 10 Vp-p; typically, place one transformer at
each end of the coaxial cable.
isolation transformer when the ground loop potential exceeds 10 Vp-p; typically, place one transformer at
each end of the coaxial cable.
Figure 1. Basic Installation of the GIT100 Transformer
GTI100