Weidmuller 2008130000, Руководство пользователя

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• When daisy chaining combiner boxes, the D+ and D– of each Transclinic should use
one twisted pair of the cable, leaving the remaining wire (in cables with 1.5 pairs)
or the remaining twisted pair (in cables with 2 pairs) for the C connection. Always
make sure that D+, D– and C use the right color-coded wire of the cable. It is a must
to connect the C pin of all the Transclinics and the RS–485 master together(see the
RS-485 wiring diagram).
CAUTION
• IMPORTANT: in each combiner box always wire the C pin first and
afterwards the D+ and D– pins.
• It is very important NOT to connect the shield to the C pin in any
combiner box (see the RS-485 wiring diagram).
Daisy-chained shield running non-stop from end to end of the RS–485
bus.
Leave the shield floating (i.e. unconnected) at the far end of the RS–485
bus
(i.e. the combiner box farthest from the RS–485 master in terms of cable
length). Tie the shield directly to protective earth at the RS–485 master
end
• Tie the C pin to protective earth at the RS–485 master end (see RS-485
wiring diagram). Before doing this please ensure that the C pin is not
connected to protective earth anywhere else in the whole RS–485 bus
(keep in mind that some RS–485 masters may already tie internally the C
pin to protective earth or to their power supply ground!). This connection
makes sure that the RS–485 common-mode voltage stays close to
earth potential instead of rising to dangerous voltages due to stray
capacitances and conductances in the network.
• Check communication schema on next page.