ZyXEL Communications PLA-470 V2 - V3.0.5 Guía de instalación descargar pdf (Pagina 162)

Direct Tap Methods

The “direct tap” methods are used to connect PLC devices directly to the network

electrical wirings by perforating the cable insulator and the electrical wiring itself.

Such methods require resorting to an electrician authorized to intervene on LV

(low voltage) or MV (medium voltage) electrical networks because of the electrical

hazard.

Figure 7.26 illustrates the operating principle of direct tap coupling.

Transformers and Meters

To design the topology of a PLC network, it is necessary to know the range of the

PLC signal over the electrical network and to identify the points of the network that

may receive this signal. In addition, the PLC network can be secured with this infor-

mation.

Some devices existing on the electrical network where PLC devices are installed

have an influence on the PLC network insofar as they can alter the signal and even

cut it off completely. It is then necessary to inject the signal at locations of the elec-

trical network where the PLC signal may not be cut off. Among the devices of an

electrical network that may cut off the PLC signal, let’s mention the following

devices in particular:

•

The transformers consisting of two coils used to change the voltage from one

value to another one. These coils act as insulators between two parts of an

electrical network; this is called “galvanic isolation.”

Transformers and Meters 143

Figure 7.26 PLC direct tap coupling

1 2 ... 157 158 159 160 161 162 163 164 165 166 167 ... 348 349

Sin comentarios

ZyXEL Communications PLA-470 V2 - V3.0.5 Guía de instalación Pagina 162