SMA Sunny Boy Control Light - Manual (Page 74)

Sunny Boy Control Light Chapter 7: Appendix
SUNBCL-11:NE
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SMA Regelsysteme GmbH
house electricity distribution
connection to
public grid
Interfering
device
1. reconnect to
other phase
2. plug
filter
Sunny Boy
Control Light
Sunny Boy Sunny Boy
Fig.7.7: Interference suppression at strong signal damping
Phase Coupler
If the communication is done with several phases, you have to consider a strong
damping resp. a significantly lower range for the data signal. If the string inverter,
contrary to our recommendation, is connected to another phase (e.g. L2) than Sunny
Boy Control Light (e.g. L1), the data transmission can only be successful if the
phases are coupled with sufficiently high frequency. In many households this is the
case by already installed three-phase current consumers (electric range, flow-type
heater and similar).
Additionally, the transmission line may be improved by the installation of a phase
coupler in the mains distribution. However, the communication over several phases
remains problematic:
Very long transmission paths result from the detour via the phase coupler, and by the
high-frequency coupling of the three phases the damping influence of electrical
devices connected to the other two phases is boosted.