PCA 2 1000D OPERATING INSTRUCTION25055055

dissimilar potential (over 10 V!) will lead to the destruction of the
RS-485 interface (e.g. lightning).
•
Except the data link “A (D+)”, “B (D-)” and “GND” (for automatic
addressing additional “ID1” - “ID2” see following chapter) no
further cable cores of the data line may be used.
•
Pay attention to sufficient distance from powerlines and motor
wires (min. 20 cm).
•
A maximum of 64 participants can be directly connected to one
another, and another 64 participants via a repeater.
Example for MODBUS connection
MODBUS
26.02.2007
v_modbus_verbindung.vsd
The data line must be conducted 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.
Recommended wire types
1. CAT5 / CAT7 cables
2. J-Y (St) 2x2x0.6 (telephone cable)
3. AWG22 (2x2 twisted pair)
Max allowed wire length 1000 m (CAT5/7 500 m).
Shielding
The use of shielded cables is normally not needed but offers high
protection against electromagnetic 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 occur-
rence of compensating currents may have to be considered if the
shield is contacted on both sides.
Operating Instructions PCA-2 1000D2 Electrical installation
L-BAL-E295-GB 1906 Index 001 Part.-No.
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