Posted 20 Nov 2017 Hey guys I don't have much experience in PLC serial communication and I'm tasked to integrate 6 OP-905 scales with our EATON based control system. The scales are rs485 asynchronous serial communication, my concern is that if the device is not designed to be an RTU then I cannot use modbus. And if that is the case how do I talk to multiple scales using the async protocol. Has anyone done this in a similar platform? Share this post Link to post Share on other sites
Posted 20 Nov 2017 https://docs.wixstatic.com/ugd/78eff6_fd68e6587fcb4427808896cd19946b91.pdf The above is the manual for the OP-905 scale. What you want to do is set the scales up for a 'command and request' mode of operation. Look at 'Commanding Format' on page 24 of the above manual. Each of the scales will have a different address. You will then send a command and get a response from each of the units. This is ASCII code out of the serial port. It will not use Modbus RTU. Hope this helps you out. Regards, Garry 2 people like this Share this post Link to post Share on other sites
