First off, let me start saying it’s a pleasure to answer such a well laid down question. Not everyone puts so much effort on explaining what they did and how they did it. Yours is a plus one question right after you finish reading it. Now with your problem. You missed one very important step … Read more
About the same time I faced the same problem – which library to choose for python modbus master implementation but in my case for serial communication (modbus RTU) so my observations are only valid for modbus RTU. In my examination I didn’t pay too much attention to documentation but examples for serial RTU master were … Read more
If I’m not getting it wrong, you’re defining your GPIO pin correctly but you’re never toggling it high and low. To be able to drive the DE/~RE signal on your RS485 chip you should take the GPIO high before you write on the bus and low right after to be able to read the answer … Read more