SMA SB 3800-U - Manual (Page 44)

5-16 SMA America SB3800U-12:SE2006
Note: The termination of the other end of the RS-485 cable
will depend on what type of device you’re connecting to. For
detailed information, please see the Tech Updates section of
our web site at www.sma-america.com There you will find
technical information on all of the Sunny Boy communication
options.
Figure 5-8 Detail of RS-485 Termination and Jumper Settings
Jumper Configuration for RS-485 Communication:
Terminal Block for
RS-485 Connections
Jumpers B & C Installed:
Jumper A installed:
Installing these jumpers puts 680 Ohm
symmetry resistors between pin 2 (Data+)
and +5V and between pin 7 (Data-) and
Ground.
Installing this jumper puts a 120 Ohm
termination resistor across pin 2 (Data+)
and pin 7 (Data-).
NOTE: Install jumpers B & C after the inverter is on
the RS-485 bus and only if symmetry of the
signal is required. (Symmetry is already
provided by the Sunny Boy Control products)
Install jumper A only, if the inverter is on one of
the ends of the RS-485 bus.
RS-485 Piggy-Back
Communication Module
Signal Symmetry and
Termination Jumpers
+ + - - L1 L2 N
2 3 5 7
C
B
A