Ingeteam AAX7051 Manual De Usuario página 18

Ingeteam
Uncertainty thresholds
RS-485 establishes two uncertainty thresholds for differential mode communications. Standard and True Fail-Safe.
Protection shield
The cable shielding protects the communication against electromagnetic noise. The grid should only be earthed at
one of the ends of the section.
The figure below depicts an example of a logic diagram for the RS-485 wiring. The signals B (+) and A (-), GND
and the protection shield are included. The units considered end of line will have the resistor.
Inverter
GND 1
R
B+
A-
Protection shield
R: 120 Ω
18
TRUE FAIL-
STANDARD
RS-485
RECEIVER
0.4 LOGIC 1
0.2
0
-0.03
UNDEFINED UNDEFINED
-0.2
-0.4 LOGIC 0
GND 2
B+
A-
Description of the communication
SAFE
RS-485
RECEIVER
LOGIC 1
LOGIC 0
GND N-1
B+
A-
AAX2011IQM02_C - User manual
GND N
R
B+
A-