If you need to save as much power as possible, you will need to use two GPIOs to command RE/ and DE independently, disabling both the receiver and transmitter when the bus is inactive (this is possible as, being the master of the bus, you know when a slave can talk on the bus). In Modbus RTU and Modbus ASCII, RS485 is used as the physical layer. Allows you to connect Modbus RTU slaves (such as sensors, energy meters, HVAC devices) to Modbus TCP/UDP masters (such as home automation systems). Por esse motivo, ele é suportado por uma ampla variedade de equipamentos disponíveis. Arduino-based Modbus RTU to Modbus TCP/UDP gateway with web interface. O protocolo Modbus é um padrão aberto, isto é: sua utilização é livre de taxas e licenciamento.
In all cases what you need is just a stack supporting the STM32 USARTs and using a GPIO to control the transceivers. on Problemas comuns no Driver Modicon Modbus Master (ASC/RTU/TCP).
Im using RS-485 serial transceiver module for interface to temperature controller and SoftwareSerial pins. It gives only 0 for each item of the received data array au16data. Im using Modbus-Master-Slave-for-Arduino library and I tried to test using example code below. Modbus RTU trades the readability of its messages for more efficient data transmission. Im trying to control a temperature controller using Arduino MEGA over SoftwareSerial. They differ in that the Modbus ASCII is more easily understood by humans as the messages it produces are in ASCII format.
It is even possible that one of the Modbus master stacks available (like the one cited by JuliusCaesar) may support this chip or a compatible one. The Modbus RTU (remote terminal unit) and Modbus ASCII are the two main modes of data transmission used in the protocol. The connections you will have to do is connecting RO to the Rx for USART6, DO to Tx of USART6 and both RE/ and DE to the same GPIO, choosing one available on the same Arduino connector, like PB4 (selected as TIM3_CH1 on the Arduino pinout, but you can change it to be a GPIO). Yes you can implement Modbus-RTU on the STM32F7 discovery board you have using the Max485 They both communicate using 3V signaling.