MODULAR SUNWAY TG
TE OD
INSTALLATION GUIDE
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139
Rev. 03
– 01/06//2018
7.3.2. RS-485 bus - multidrop connection
Figure 46: Multidrop connection diagram
The RS485 multidrop line to multiple devices must be wired using a linear and not a star topography: each
device connected to the line must be connected by an incoming cable from the previous device and have
an outgoing cable to connect the next device. The exceptions are obviously the first and last devices in the
chain which, will have only an outgoing line and an incoming line respectively.
Elements participating in a RS485 section are called nodes. The maximum number of nodes which can be
connected on a section is limited to the following aspects:
•
Logic limit of the bus, equal to 247
•
Length of the connection
•
Transmission speed
•
Electronic drivers used
The limit set by the line drivers used in SUNWAY TG TE inverters is 30 devices. It is not advisable to use
section lengths exceeding 500m. Should it be necessary to connect more than 30 devices on the same line
or over a length exceeding 500 m, it is advisable to break the connection up into more than one section
using RS485 repeaters.
NOTE
The RS485 bus default rate is 38400 baud. It is not advisable to exceed this value. In the event
of communication disturbances, it is possible to set the rate at a lower value (19200 or 9600
baud).
7.3.3. COM1 port
Serial Port
Options Required
Optically Isolated Port Terminal and contacts
COM1
String monitoring
Yes
DC.X11-1: A (D1)
DC.X11-2: B (D0)
DC.X11-3: 0V
Table 21: COM1 serial port connection
G
alvanic isolation between the inverter’s COM1 serial port and the external communication devices is
obtained by means of the RS-485 ES914 board, integrating the following:
•
An INVERTER port for the connection between the isolation board and the inverter
