SMA SI 4548-US - Manual (Page 124)

14 Connecting External Sources SMA America, LLC
124 SI4548-6048-US-BE-en-20 Operating Manual
Load-Dependent Start
In case increased energy demands arise, the generator can be requested for support. This function
can be switched on or off (default) using the parameter "235.09 GnPwrEna". The function is only
effective if the parameter "235.01 GnAutoEna" is simultaneously set to On.
The load limit for the request and the generator stop is configured using the parameters
"235.10 GnPwrStr" and "235.11 GnPwrStp". The average time by which an average value for the
load power is calculated can be set using "235.12 GnPwrAvgTm". This prevents temporary power
consumption peaks of a few seconds from causing a power-dependent generator start.
If the generator has been started due to the load, it runs according to the minimum generator run time.
If, once this time has expired, the average power is below the cutoff limit, the generator is stopped
again.
The following flowcharts provide an overview of the start/stop behavior of the Sunny Island during
automatic generator operation:
Generator Interface "234.07 GnSrtMod" = Manual; Request Via Sunny Island
Reaching the float charging process
If the float charging process (see Section 13.5 "Charge Control", page 110) is activated before
the cutoff limit (GnSocTm1Stp or GnSocTm2Stp) is reached, the generator request is disabled
again. If a full or equalization charge is active, the generator is only stopped after this charge
is completed and not when "235.04 GnSocTm1Stp" or "235.06 GnSocTm2Stp" is reached.
Multi-Phase System
Only the total load power of all line conductors is monitored. Individual line conductors in a
multi-phase system are not monitored.
The load power is calculated using the Sunny Island power (parameter "111.01 TotInvPwrAt")
and generator power (parameter "131.01 TotExtPwrAt").
1 Generator is requested via Sunny Island
2 Manual generator start
3 "Generator is running" detected, beginning of warm-up phase
4 Warm-up phase is completed, connection
5 Generator current limit
6 Minimum run time has expired
7 Current is reduced, battery absorption phase
8 Charging process is completed, request signal is disabled
9 Manual generator stop
10 Generator separation
11 Stop time has expired