User Manual

EMpro - multifunctional energy measuring devices for DIN rail mounting
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PHOENIX CONTACT 109357_en_00
11.2.2.2 Using connections and designations
Figure 11-6 Connections and designations
The RS-485 interface has four assigned terminals.
The non-inverted signal can have the following designations: A, +, A+, TxD+/RxD+, D+
The inverted signal can have the following designations: B, -, B-, TxD-/RxD-, D-
To ensure that the communication is guaranteed even in the event of malfunctions, ensure
that the following conditions are met in the RS-485 network:
– Twisted pair conductors (A and B) (stranding)
– Shielded conductors (GND)
– Termination resistors (and a bias network)
NOTE: If you want to activate the integrated 120  resistor, bridge the terminals  and A+.
GND: Shield of signal line
B- and A+: Signal lines
: 120  resistor
Internal
GND
B-
A+
Ω
Ω