SMA Sunny Boy Control - Manual (Page 101)

Sunny Boy Control
SMA Technologie AG
User Manual SUNBC-14:NE0206 97
For the COM3 port, jumpers A, B, and C are in the opposite order of
what they are for the COM1 and COM2 ports!
Jumper A: Termination of the RS485 cable. The data cable must be
terminated on both ends by either setting jumper A or bridg-
ing pins 7 and 9 of the connector. The required resistance is
120
Ω . The default setting is “not terminated”.
Jumpers B and C: Pull-up/pull-down resistances for the RS485 signal. The
RS485 pull-up/pull-down resistances are achieved by either
setting jumpers B and C on the Sunny Boy Control or using
a cable plug with integrated resistors. The required resis-
tances are 680
Ω . The default setting is “pull-up/pull-down
activated”. Only one device on the RS485 bus needs to
provide the pull-up/pull-down resistances.