is it possible to transmitt RS485 data over Bluerobotics 300m tether? will it cause attenuation when we transmitt it to a large distance?
Have a look at their Bluart product.
You can plug it to the raspberry pi and send the data through Ethernet.
Alternatively, you can get a network switch and an Ethernet to 232 interface subsea and at surface and get 232 to 485 converters…
It depends on the data rate - I think you should be able to run a sonar over a spare twisted pair for 300m.
I ran 485 up the 300m tether, had issues, you get a lot of cross talk and drop outs. Integrating the Bluart board into our system to combat that issue. The wires not being shielded is the issue.
Hi…the RS-485 standard conforming drivers provide a differential output of a minimum 1.5 V across a 54-Ω load, whereas standard conforming receivers detect a differential input down to 200 mV. The two values provide sufficient margin for a reliable data transmission even under severe signal degradation across the cable and connectors. This robustness is the main reason why RS-485 is well suited for long-distance networking in noisy environment.