Electronic – Should I consider using RS-485 for the next project


I am planning on an automation project that will be using several different sensors including but not limited to: Temperature, Barometric Pressure, Air flow, Humidity, etc.

As I was talking with someone they mentioned that I should look into RS-485 as a means to connecting my sensors to my controller. Then ultimately to the PC.

After a quick search I gathered some information about RS-485 but now I am wondering if it's over kill or if it's even used now a days?

Couldn't I just use a microcontroller that has enough inputs and interface with the PC using USB?


EDIT: Ok if distance to controller and environment (in my case an industrial application) then RS485 might be useful. Are there other bus alternatives that might be more useful?

Best Answer

I've used RS485 to connect multiple data-loggers together over distances of up to 100m. In this application it worked perfectly.

I haven't used RS485 to connect sensors directly to a controller but if you have sensors with RS485 outputs + a controller that supports RS485 and you have more than 10 sensors or the sensors need to be more than a short distance from the controller I would definitely use RS485 instead of analogue wiring. I found that as you add more and more analogue sensors to a controller (in my case, a data-logger) small issues with power supply noise, wire impedance and environmental interference suddenly become big issues.