I had great difficulty getting my Arduino Opta set up and working using the Arduino PLC IDE – whatever I tried I got the “Cannot download Sketch file (error code: 1)” error.
I finally had success using the plain Arduino IDE to do the initialization and then switching to the Arduino PLC IDE. The final step was changing the Modbus address to 247.
It probably shouldn’t be that tricky….
I have the same issue, “Cannot download Sketch file (error code: 1)” error.
Com port OPTA: 9 and 16 on my pc,
hope 9 is for IDE and 16 for PLC IDE; also changed the modbus port. but no luck