What does 'resultMain' say after the readHoldungRegisters call? Is the address you are attempting to read valid on your frequency inverter?

Second, pins 0 and 14 look odd for the ESP32's UART2, especially the 0. I know of no ESP32 that has a serial line on pin 0, since that is used for boot etc ...

Hi everyone,

I'm trying to do ESP32 communicate with a Freq. Inverter using MAX485 converter. I'm using the library ModbusMaster with Arduino IDE.

I tested a Arduino UNO instead the ESP32 and it worked fine.

With the ESP32 I can only write to the Inverter, but not read.

Did someone foundout the ...

Hi everyone,

I'm trying to do ESP32 communicate with a Freq. Inverter using MAX485 converter. I'm using the library ModbusMaster with Arduino IDE.

I tested a Arduino UNO instead the ESP32 and it worked fine.

With the ESP32 I can only write to the Inverter, but not read.

Did someone foundout the ...