SMA SB 3800-U - Manual (Page 43)

SB3800U-12:SE2006 SMA America 5-15
RS-485 Communication
RS-485 is a communication standard for bidirectional transmission of data between one
or more Sunny Boy inverters and a PC.
Note: All Sunny Boy inverters are capable of RS-485
communication. You can mix different Sunny Boy models on the
RS-485 communication bus.
Requirements for RS-485 Communication:
• The Sunny Boy 3800U must be equipped with an RS-485 Piggy-Back communica-
tion module.
• The cable should be no longer than 1200 meters (4000 feet) with a common shield,
and a wire size no smaller than 24 AWG. Use the cable type specified in the RS-
485 Tech Note on www.sma-america.com.
• RS-485 cables are available from SMA America.
• Conduit may be required for communication wiring, per local electrical code re-
quirements.
Connecting an RS-485 Cable
Use the following procedure to install an RS-485 data-communication network:
Note: The following steps describe how to connect one or
more Sunny Boy inverters to an RS-485 bus. For more
information on connecting more than one inverter to an RS-
485 bus, please see “Technical Note: RS-485
Communication” in the Tech Updates section of our web site
at www.sma-america.com
1. Connect the three wires of the RS-485 cable to terminals 2, 5, and 7 of the
communication terminal block as shown in Figure 5-8. Record the wire color used
for each of the terminals. Two communication knockouts are provided for
connecting multiple Sunny Boys on an RS-485 communication bus.
2. Connect the shield of the cable to the Sunny Boy 3800U’s case. (See Figure 5-8)
Do NOT connect the cable shield to the PC’s DB-9 connector. The shield must
remain floating at the PC.
3. Install a jumper in position A, the bottom set of pins on the communication jumper
block, to set it for termination. (See Figure 5-8)