AERMEC prd 1 Manual De Uso página 7

Electrical connections
Connect the RS485 serial line leaving the power sup-
ply "RJ12 power supply" to the supervisor input on the
µC2, using a twisted pair cable with shield. Power ter-
minals G-G0 from a transformer with a 250 mAT fuse.
Make the connection between the power supply "RJ12
power supply" and the terminal using the telephone
cable supplied. If the cable is not long enough, use a
pin-to-pin telephone cable with a maximum length of
40 m.
Set
Prg
transformer
not supplied
230V~50Hz
Maximun RS485 distance
Cable characteristics
Cross-section
PRD1
Sel
d
Telephone cable
(standard supplied)
Insert 120 ohm terminal resistor
betweenTx/Rx+ and Tx/Rx- for
lines longer than 20 m
L MAX = 1000 m
Serial cable
250 mA
24 Vac 3VA
Speed
Warnings:
• only use safety transformers;
• for safety reasons a 250 mA slow-blow fuse must be
fi tted in series with terminal 'G';
• if using the same transformer for the µC2 and the
terminal, respect the polarity G-G0 as per the wiring
diagram. Reversing the polarity is the same as short-
circuiting the secondary of the transformer;
• do not earth the secondary of the transformer.
RS485
Power supply line
Typical length
250 m
100 m
50 m
Serial line to microchiller
19200 baud
1000 m (with 120 ohm terminals)
twisted pair + shield
0,35 mm
microchiller 2
Resistor
not supplied
120 Ohm ; 0,5 W
G + -
G + -
Minimun cross-section
1,5 mm
0,5 mm
0,35 mm
2
2
2
2