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5.7.2 Power supply connections
In the above circumstances, the resistance can be overlooked
in the majority of cases. More care must be taken, however, if
the cable has to carry power: in this case, the resistance could
cause a significant drop for the purposes of correct operation of
the device you intend to power.
Supposing we have a run of 100m of cable powering a device
with consumption of 100mA. Using Ohm's Law 1, let us analyse
the voltage drops for a range of sections:
0.22 mm² : V=R*I = 17*0.1 = 1.7V
0.50 mm² : V=R*I = 6.4*0.1 = 0.64V
0.75 mm² : V=R*I = 5.2*0.1 = 0.52V
1 mm² :
V=R*I = 4*0.1 = 0.4V
This is why it is important to size the power supply conductors
correctly.
V = R * I. The estimated drop in Volts is equal to the total resistance
of the circuit, expressed in Ohms, multiplied by the circulating
current I, expressed in amps.
To connect the IP module from the Vedo control panel to a data
network, you need to go through a hub or a network switch. The
control panel will be connected by means of a network cable in
straight configuration. In many cases, it will be possible to buy a
standard cable of suitable length, but when this is not possible,
you will need to make the connection autonomously.
This is done using UTP CAT5 cable or higher.
The cable will be terminated at both ends with RJ45 plugs with
the aid of a specific crimp tool. Both RJ45 plugs must be wired
in the same sequence as shown in the figure.
The conductor colours shown in the figure must be rigorously
observed. Non-conformance with the colours may cause the
connection to work intermittently or not at all.
Procedure:
1.
Remove about 5 cm of jacket from the cable so as to make
the 4 pairs of wire accessible
2.
Separate the conductors in the pairs
3.
Stretch the conductors out so as to straighten them, and
place them in the order shown in the figure
4.
Adjust the length of the conductors to about 12mm
5.
Insert the conductors as shown in the figure (the connector
is illustrated as seen from the side)
5.8 DATA NETWORK CONNECTION CABLE
