•
ID - ID1/2 = yellow (for automatic addressing for MODBUS Master)
•
GND = white
Information
•
You must ensure correct connection; i.e.
“
A (D+)
”
must also be connected on the following devices
to
“
A (D+)
”
. The same applies to
“
A (D+)
”
.
•
Inaddition,a "GND" connection must be established, as dissimilar potential (over 10 V!) will lead to
the destruction of the RS-485 interface (e.g. lightning).
•
Except for the data link
“
A (D+)
”
,
“
B (D-)
”
, the
“
ID1 - ID2
”
(automatic addressing for MODBUS Master)
and the
“
GND
”
connection, no further cable cores of the data line may be used.
•
Pay attention to suf
fi
cient distance from powerlines and motor wires (min. 20 cm).
The data line must be connected from one device to the next. No other type of wiring is allowed!
Always use only two wires of one lead (twisted pair) for the connection.
MODBUS connection
MODBUS
26.02.2007
v_modbus_verbindung.vsd
Recommended wire types
1. CAT5 / CAT7 cables
2. J-Y (St) 2x2x0.6 (telephone wire)
3. AWG22 (2x2 twisted pair)
Max. allowed wire length 1000 m (CAT5/7 500 m)
Shielding
The use of shielded cables is normally not demanded but offers high protection against electro-
magnetic interferences, especially high frequencies. However, the effectiveness of the shield depends
on careful installation of the line.
If shielded cables are used, the shield should be placed at
“
PE
”
on at least one side (preferably on the
master connection). The occurrence of compensating currents may have to be considered if the shield
is contacted on both sides.
Shield connection correct
Shield connection incorrect
Information
If any matters are unclear, please contact our V-STE support department for control systems -
ventilation technology. The information sheet "Network structure of MODBUS" R-TIL08_01 contains
detailed information about "MODBUS".
Operating Instructions
UNIcon MODBUS Master
Electrical installation
L-BAL-E207-GB 1723 Index 003
Part.-No.
12/114