Hello, I am trying to read the power output of my inverter (ABB PVI-3.0-TL-OUTD) and I flashed your code as it is, only changing the pin mapping.
I am using a Wemos D1 mini board, connected to an RS485 to TTL board (MAX485) through a level shifter.
Connections are made as following:

[Board to module]
rxPin (0) -> RO
txPin (5) -> DI
rtsPin (4) -> RE, DE

[Module to inverter]
A -> +T/R
B -> -T/R
RTN -> GND
LNK disconnected

Output I'm getting on the console:

09:17:11.072 -> Error Code 
09:17:11.072 -> Values for Debugging: 
09:17:11.120 -> 0. Wert: 2 1. Wert: 59 2. Wert: 3 3. Wert: 0 4. Wert: 0 5. Wert: 0 6. Wert: 0 7. Wert: 0

The inverter address is correctly set and the terminator resistance is set to ON. I must be missing something, thank you for your help.