Additional Functions
SMA America, LLC
104
SI5048U-TUS121440
Technical Description
12.6 Automatic Frequency Control (AFC)
Clocks that depend on the stability of the grid frequency for their accuracy become increasingly
inaccurate when there are constant frequency deviations. Frequency fluctuations, i.e., deviations from
the nominal frequency, occur, for example, in off-grid power systems that operate with a diesel
generator.
The ”
A
utomatic
F
requency
C
ontrol (AFC)” (German: AFRA) function of the Sunny Island allows the
use of clocks in these types of off-grid power systems. This function is activated using the
”250.11 AfraEna” parameter.
The time deviation is compensated on average.
12.7 Time-Controlled Standby
You can set the Sunny Island to standby mode in a time-controlled way. Activate the time-controlled
standby using the parameter ”250.13 SlpAtNgt”. Set the parameter to ”Enable”.
After activation set the start and stop times for the standby. Carry out the setting via the parameter
”250.14 SlpStrTm” and ”250.15 SlpStpTm”.
12.8 Reaction in Case of Faults in a 3-phase system
Using the parameter ”250.30 RnMod” you can influence the behavior of the Sunny Island in a
3-phase system in case of a fault. The parameter is set to ”RunAlways” at the factory. This means that
the Sunny Island master ignores all faults at the slave devices.
If you set the parameter to ”StopAlways” the system will be put in standby mode upon detection of a
fault at the slave devices. Faults which can be removed via an autostart are not included.
Display of messages
Messages can be displayed at any time while the device is in operation and they have
priority over the Home Screen display.
Quartz-controlled Clock in the Sunny Island
The internal clock in the Sunny Island is quartz-controlled and thus operates correctly
(within the tolerance limits). The adjustment refers to externally connected clocks that
depend on the grid frequency.
