SMA STP 50-40 - Connection to the Multifunction Relay

6 Electrical Connection
SMA Solar Technology AG
Operating manualSTP50-4x-BE-en-2346
Reporting the switching status of the grid relay
The multifunction relay can trip a signal to the grid operator as soon as the inverter connects to the
utility grid. To enable this function, the multifunction relays of all inverters must be connected in
parallel.
1 kΩ
B F
1
2
3
B F
1
2
3
B F
1
2
3
=
Signal to
grid operator
Inverter 1:
Grid relay closed
Inverter 2:
Grid relay open
Inverter n:
Grid relay open
max. 30 V
DC
Figure 14: Wiring diagram for signaling the switching status of the grid relay (example)
6.4.4 Connection to the Multifunction Relay
Requirement:
☐ The technical requirements of the multifunction relay must be met (see Section13, page120).
Cable requirements:
☐ Conductor cross-section: 0.2mm² to 1.5mm²
☐ The cable type and cable-laying method must be appropriate for the application and location.