10 Performing The Vac Test - SMA NR-STP-AST10-12 Replacement Manual

SMA Solar Technology AG
16. Perform the respective measures indicated when the following LED status appears:
LED status
Green LED is
flashing
The red LED is
glowing and an
error and event
message appear
in the display.
17. After replacing the assembly, check the correct functioning of the SELV circuit. Activate the fan
test for this purpose:
• Call up the user interface of the communication product or software and log in as Installer
or User.
• Select the parameters Device > Cooling system > Fan test. If the fan starts, the SELV
circuit is fault-free. If the fan does not start, contact Service.
18. Ensure that the inverter feed in correctly.
19. Perform the VAC test (see Section 10, page 25).

10 Performing the VAC Test

Due to the replacement of the assembly, elements in the supply voltage measurement area were
replaced. To ensure that the supply voltage measurement in the inverter has the required accuracy,
the installer must carry out a VAC test.
The VAC test compares the AC voltage present in the utility grid with the AC voltage measured by
the inverter. The inverter may display up to 5 V more or 1 V less than the applied AC voltage.
Requirements:
☐ A measuring device suitable for the VAC measurement must be available.
☐ During measurement, devices causing fluctuations in the utility grid (e.g. other inverters) must
be switched off or set to Stop.
Procedure:
1. Log into a communication product (e.g. Sunny Explorer) using the "Installer" user group and
establish a connection to the inverter (refer to the communication product manual).
2. Set the parameter Operating mode from MPP to Stop.
3. Make sure that the VAC voltage measured by the inverter is displayed. This can be done on
the display of the inverter or via the communication product.
4. Measure the AC voltage as close as possible to the inverter.
5. Compare the measured AC voltage and the AC voltage displayed on the inverter.
Replacement Manual
Cause
The DC input voltage may still be
too low or the inverter is monitoring
the utility grid.
The inverter has detected an error.
10 Performing the VAC Test
Measures
Wait that the DC input voltage is suf-
ficiently high and the grid-connec-
tion conditions are met. Then the in-
verter will start operation automati-
cally.
Eliminate the error (see the inverter
manual).
AST-STPTL10-RM-xx-10 25