Ingeteam AAX7051 Manual De Usuario página 17

Description of the communication
2. Description of the communication
It is possible for the Ingeteam inverters to communicate via RS-485 using the corresponding accessories. This type
of communication is master-slave. The network master shall be a PC, PLC, etc., responsible for monitoring and
configuring the slave inverters of the installation.
2.1. Overview
RS-485, as the standard EIA-485 is generally known, defines the electrical characteristics of the transmitters and
receivers of a low-cost system for digital communication in hostile electromagnetic areas. The robustness against
noise is due to the communication mode being differential, in other words, the information is transmitted on a
pair of wires that are usually braided, where the signal of one is inverse to that of the other. The standard EIA-485
defines signal B as the 'non-inverted' or positive (+) pin, while signal A is the inverted or negative (-) pin.
Topology
The distribution of the cabling is a number of consecutive nodes, also called a bus or line. Installation in a star or
ring formation, and other topologies, are not allowed.
In a bus topology, the master should remain at the center of the bus for its signal to reach the highest number of
slaves with the greatest strength possible.
Serial parameters
Communication in the INGECON units is 9600 bps with 8 bits of data, with no parity bit and with 1 stop bit.
Half Duplex
The communication via RS-485 line in the INGECON units is done in Half Duplex mode. In this configuration, the
information both sent and received is transmitted through the same pair of wires.
Wiring
Solar PV plants are habitually wired with large flows of energy that can have a negative effect on communication.
Ingeteam establishes the following guidelines for the design and wiring of the installation:
• The conduit for the data wiring must be used exclusively for this wiring. This conduit must be as far as
possible from the power lines and other sources of noise.
• The total distance of wiring shall be as short as possible, centering the master on the bus and avoiding a
total branch length of 40 m.
• Braided shielded pair type cable with characteristics impedance of 120 Ohm shall be used. One braided
pair shall be used for the pair of the signals B (+) and A (-), and the other for the GND.
• Although the data is transmitted on a pair of wires, the wiring of the GND must provide a voltage
reference shared by all the devices connected to the bus.
End of line
120 Ohm end of line resistors must be installed at the two ends of the RS-485 wiring. The Ingeteam units
incorporate these resistors.
AAX2011IQM02_C - User manual
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