Fronius Rapid Shutdown Box Duo - Triggering and Resetting Rapid Shutdown; Triggering Methods; Performing a Reset

Description: The inverter detects insufficient DC voltage at the input for grid power feed
operation. If this service code occurs over a longer period of time despite the presence of
solar radiation, the following steps can help to find the error:
- Check the position of the DC disconnector on the inverter - should be ON
- Read the DC voltage on the display or measure it at the inverter terminals
- If the DC voltage is 0 V, this means that either the Rapid Shutdown Box is not
being supplied by the PV field or there is no electrical connection between the
Rapid Shutdown Box and the inverter. Check DC cabling including the Rapid
Shutdown Box inputs! With the Rapid Shutdown Box - Quattro at least one
string must be connected to input 1.
- If the DC voltage is approximately 28 V, this means that the Rapid Shutdown
Box is being supplied and is waiting for the release on the signal ports. Check
the wiring of the signal loop and the position of all switches in the signal loop!
- If the service code is still present despite solar radiation, contact your system
installer.
Triggering a rapid
shutdown
Two different types of rapid shutdown can be triggered depending on the configur-
ation and on-site installation:
- Via loss of AC connection (only for the SnapINverter inverter series): If the signal
loop has been connected to the inverter (see chapter Connecting the Rapid Shut-
down Box to GEN24 Inverter on page 17), a rapid shutdown can occur by inter-
rupting the AC connection. The inverter detects a failure of the AC connection and
switches off the connection to the solar modules via the Rapid Shutdown Box. The
lines are discharged and isolated.
- Via external switch: If failure detection via the AC connection is not suitable or
additional options are required, external switches can be installed in the signal loop
(see chapter SnapINverter: Connecting the Rapid Shutdown Box to an emer-
gency stop button on page 19). The Rapid Shutdown can then be triggered by
pressing one of these switches. The lines are discharged and isolated.
Performing a
reset after a rapid
shutdown
To restart the PV system after a rapid shutdown:
- If the signal line to the inverter is closed, there must be an AC connection present to
restart the PV system.
- Open the switch that was used to trigger the rapid shutdown
- Check all other external switches in the signal loop to see if they are closed.
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