SMA SUNNY ISLAND 4548-US Operating Manual page 121

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GenReq signal
The GnReq signal (see Section 15 "Relays", page 140) is set for signaling the generator request
and can thus be used as an alarm contact (in this case: a bulb). If no request is pending, the
signal is reset.
If an internal request is sent while the generator is already running, the signal is disabled until
the generator is externally stopped and the stop time has expired (30 seconds).
Disconnecting the generator
A disconnection device should be positioned between the Sunny Island and the generator. If
the generator is to be stopped, it is first manually disconnected using the disconnection device
and then it is stopped. This prevents actuation of the generator by the Sunny Island.
Autostart
This allows autostart generators to be directly integrated. They have a separate internal controller that
controls the start procedure.
The Sunny Island requests the generator via the GnReq signal. If the generator voltage and frequency
are within the set limits (see Section 14.1.6 "Limits and Power Control", page 126), the device is
synchronized and connected following the warm-up time.
The Sunny Island keeps the request signal active until a disconnection is made and the set
power-down time has expired.
Shut-off delay
Autostart generators can have an internal after-run cycle that is only activated when the request
has been disabled. This may result in a longer power-down time.
Internal warm-up phase
With some generator types, the voltage is only switched to the output after the internal warm-up
phase is finished. This is why generator connection is internally time-monitored:
• 2 x "234.12 GnWarmTm" + 2 minutes for manual and automatic start
The following figure shows the wiring for a generator capable of autostart:
Operating Manual
14 Connecting External Sources
SI4548-6048-US-BE-en-21 121