Activate the diagnostic function in the event of a defective Speedwire communication

If several Speedwire devices in line topology are connected to each other in the system and the Speedwire communication does not function properly, you have the option of activating diagnostic functions for simple troubleshooting.

The following diagnostic functions are available:

  • Activate Speedwire communication display on the inverter

  • Test Speedwire communication via SMA Data Manager

Activating the Speedwire Communication Display on the Inverter

By activating this diagnostic function, the inverter can signal that one network cable is connected by the blue LED flashing. This allows you to quickly check whether the network cable is plugged in for inverters where only one network cable is to be connected, and whether only one rather than two network cables are connected for inverters where two network cables are to be connected.


  1. In the parameter group Device > Operation, select the parameter Ethernet link diagnostic via LED and set this to On.
  2. Blue LED flashes (2 s on and 250 ms off): one network cable is connected to the inverter.
  3. Blue LED is not flashing: No network cable is connected.
  4. Check whether for the inverters where the blue LED is flashing there really should only be one network cable connected or whether two network cables should be connected here.
  5. Check whether for the inverters where the blue LED is not flashing there really should not be a network cable connected.

Testing the Speedwire Communication via SMA Data Manager

If there is a SMA Data Manager in the system, the inverter can indicate signal whether the Speedwire communication is working properly or if there is a problem by the red LED flashing. The diagnostic function can only be activated via the user interface of the SMA Data Manager.


  1. Select the Communication diagnostic parameter via the SMA Data Manager user interface and set it to On.
  2. The red LED of the inverter flashes (250 ms on and 250 ms off): The communication of the Speedwire devices connected in line topology is working perfectly.
  3. If the inverter's red LED does not flash, the Speedwire communication is defective. The communication path must be checked.