Open DTU & Herf 1600

[cha-ly]

Any there any open DTU user with a Herf 1600 inverter.

Here communication with the Herf 1600 is fine,
I have an issue with the Herf AC power - either the inverter produces too low AC output (´defect?) or the conversion is inaccurate.
I use 2x 550Wp (MPPT1 & MPPT2) but see only peak AC power level under 50W.
Connecting one of the 550Wp panels to a Hoymiles HM600 I see a reasonable of 350W (AC) Panels are 270Deg, pure West, ~ 45 Deg elevation.
Dead inverter with low AC output???

[stefan123t]

@cha-ly did you measure the 50w AC output using a clamp multimeter or something similar in the AC line or is this the value from OpenDTU only ?

[cha-ly]

@stefan123t Thanks for your hints. Yes measurements confirmed the low output.
Sice I have reset the Herf 1600 inverter to its default values three times in a row and left it off for some minutes.

Back online the nominal output power was back.
May be the internal microprocessor hang?
Even though the inverter is in a (screened) metal housing it may not be immune towards high local RF fields..
I am active radioamateur and I have seen a lot of electrical equipment to suffer from poor immunity.

DC strings of PV Inverter often pick up RF signals like an antennae in particular if the line gets resonant.
As a precaution I will add some clap Ferrites on the DC inputs.
The string voltage is quite low, (under 50V) so adding a simple DC filter should cure the issue if it happens again.
thanks
Karl