We finally managed to perform our RS485 testing yesterday, which involved an Omega2S+. It turns out that waiting on flush blocks for around 30ms. This was way too long for us, so we ended up calculating our time-on-wire and rounding up to the nearest ms. Given 115200 baud, start/stop bits, and a 41-byte fixed payload size, waiting 4ms worked out about right (it took about 3.7ms for the send to complete when observed by the scope). Given also that it takes about 1.5ms for our microcontroller to process the data and reply, things are working out quite well. Our Omega does RS485, although it'd be so much nicer if we didn't have to fudge the timing. Also, ttyS0 is used for the console, hence being conflicted when trying to use it for our purposes. All good.

@Tushar-Borhade said in Modbus RS485 implementation using UART1 and TTL module: ..but what about software integration? In python? MinimalModbus is an easy-to-use Modbus RTU and Modbus ASCII implementation for Python with very good documentation. You should install (after an opkg update) opkg install python opkg install python-pyserial opkg install python-pip pip install minimalmodbus Good luck!

Hello, I would be very interested in your omega to Modbus RTU as I would like to control an inverter which has Modbus from a PLC that works through the Omega onion.

@Lars-Tobias-Skjong-Børsting said in Connect Omega 2 to UART tx1 and rx1 using Mini Dock: I have this TTL UART to RS-485 board: https://www.aliexpress.com/item/5PCS-MAX485-RS-485-Module-TTL-to-RS-485-module-Raspberry-pi/32579369267.html I think your module is same or very similar like this: MAX485 MODULE RS-485 TO TTL CONVERTER so it is not designed for Raspberry Pi. On Omega2 at least at the RO pin of MAX485 some kind of 5V to 3.3V level shifting is needed. The simplest solution: put a voltage divider between RO and RX1. And you should connect the pull-up resistors of input pins (DI, DE, RE) to 3.3V. RS-485 can be made full-duplex by using four wires ie. two twisted pairs. Is your Modbus slave full-duplex? BTW you could build also full duplex config with two of your MAX485 modules.