I have a TTL to RS485 converter which is hooked up with Arduino Nano for transmitting temperature sensor data. This circuit is working fine and RS485 output is tested by connecting to a PC via a RS485-USB converter . Now i want to connect this circuit to a PLC via an RS485 to ethernet converter. Any additional information is required for doing this? Like register address? I am a Novice in electronics.

 

TTL and RS-485 are fundamentally voltage standards. There is no specification on bit rates and data encoding.
If you want to interface to a PLC you will have to get the PLC specifications, such as baud, parity, stop bits, and just as importantly, the data encoding protocol.