Connections; Dcfit Power Supply - Videotec DCFIT Manuel D'instructions

Connections

Cables and distances
It is advisable to use the following types of cable for correct operation of the system:
Cable for RS485 line (Terminals A and B of J1)
Use a twisted pair telephone cable with a minimum section of 0.22 mm² (AWG 24). The maximum distance that
can be reached with the RS485 line is 1200 metres.
Power supply cable (Terminals GND and 12V
Use a pair of cables with a minimum section of 0.22 mm² (AWG 24). The DCFIT must only be powered by a
12V= power supply. Therefore a suitable power source must be used (never use non-stabilised power
supplies with voltages greater or less than 12V=). The power supply cables must not be too long, especially
if power is supplied by the SMXXA matrix (maximum distance of 50 metres). In every case, we recommend
installing the DCFIT as near as possible to the matrix or the local supply that powers it.
Cable for Current Loop line
A pair of cables or three cables may be necessary depending on the devices that are used. In both cases it
is advisable to use a cable with a minimum section of 0.22 mm² (AWG 24). The maximum allowed distance
depends on the circumstances: 1500 metres in the case of 3-cable transmission (DCS2, KEYPLUS, SWC16
and SW164OSM) and 500 metres in the case of 2-cable reception/transmission (SW42REM, SW82REM,
DCMT8, SWC4 and SWC8).

DCFIT power supply

For a correct power supply, the DCFIT interface requires a 12V= voltage applied over the J1 terminals
which are marked by the words: 12V= and GND (POWER, see Figure 1 on page 5). Apply the positive of
the 12V= to the 12V= terminal and the negative to the GND terminal.
Once power has been supplied, the LD1 LED will start flashing (the interface is on and operating).
=
of J1)
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