Rs-485 Wiring - Pyronix PCX 78 Installation Manual

5. If an expansion module with a power supply on board is connected, the D2+ terminal must
not be connected between the main bus and module.

RS-485 Wiring

Cable type
4 core alarm cable
6 core alarm cable
doubling D1 (0V) and D2
(12V)
Twisted pair
Figure 2: Star Wiring example
PCX Installation Guide
Screened Cable Bus range
(m)
Use when bus located 300 m
near fragmented 230V
1000 m
AC mains power line
1000 m
102017852 - V01
Wiring Format
Daisy Chain Range Star Range
1000m 50 m
For greater than 1000m
range, standard isolated
RS485 repeaters are
required.
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