29
EN
Connection with the Master inside the
network
12 OPERATING INSTRUCTIONS FOR
CONNECTION VIA AN RS485
SERIAL LINE
• When making the electrical connections in a net-
work of fan coils communicating via a serial line,
extreme care must be paid to some important
details :
1. type of cables used: twisted pair with shield, 24
AWg, flexible
2. the overall length of the network must not ex-
ceed 700/800 metres
3. a maximum of 20 fan coils can be connected
RS485 data cable characteristic impedance
120 Ohm configuration 1 x 2 x AWG24 (1 x
2 x 0.22 mm²)
• Installation notes
• the cables should be tightened to a force of less
than 12 kg. Higher forces may fray the wires and
reduce the transmission properties;
• do not twist, knot,crush or fray the wires;
• do not lay the signal cables and power cables to-
gether;
• if the signal cable needs to cross a power cable,
make sure the intersection is at 90°;
• do not join sections of cable. Always use one sin-
gle cable to connect the units together;
• do not excessively tighten the wires under the
connection terminals. Strip the end of the cable
with care. do not crush the cable at the cable
glands or safety supports;
• always observe the positions of the colours corre-
sponding to the start and end of the connections;
• once having completed the wiring, visually and
physically check that the cables are in good con-
dition and correctly positioned;
• install the cables and the unit in such as way as
to minimise the possibility of accidental contact
with other power cables or potentially dangerous
cables, such as the cables for the lighting system;
• do not lay the 12 Vac power cables and commu-
nication cables near power devices, lights, anten-
nae, transformers or hot water or steam pipes;
• never position the communication cables in any
conduits, pipes, junction boxes or other contain-
ers together with the power cables or the lighting
system cables;
• always ensure there is adequate separation be-
tween the communication cables and all other
electrical cables;
• keep the communication cables, and the units
themselves, at least 2 metres away from units with
significant inductive loads (distribution panels,
motors, generators forlighting systems).
12.1 Earthing the network
When performing the serial connection between the
units, follow the connection symbols :
• Clamp “d-” with clamp “d-”
• Clamp “d+” with clamp “d+”
• Clamp “0” : connect the shield of the serial cable.
• Never reverse the connections.
Summary of Contents for QCV-MB
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