I have an 5Kw ABB Uno inverter connected to the output of the Multiplus. The ESS has some reduce power and disconnection frequencies set. But when the Multiplus tried to limit the ABB power, the power temporarily went off for a fraction of a second (enough that all my electronics restarts), and I got a Error code: #39 - PV Input shutdown.
How can I start to diagnose the problem?
The output frequency momentarily goes to 51.8Hz
The settings on the ESS are here 
And I have the what I think are the equivelent frequencies on the ABB
F>> Grid over-frequency (OF) threshold (extended range) to 52.7
and
F> Grid over-frequency (OF) threshold (restricted range) to 50.2
