Voltage RS485 14V?

Hello,

I’m want to couple my ventilation unit to my MKR1000. Before I hook them up I wanted to be sure the RS485 levels are at 3.3V, as I read the MKR1000 does nto cope with 5V.

The ventilation unit uses a 75176B chip. From the specs I think to understand it operates at 5V. So I think I can build a voltage divider with 2 resistors to get 3.3V.

But my main concern now is when I read out the input voltage on the 75176B chip, it is 14V. Is this possible? Does this mean the signals are also of a highr voltage? When I read the tension between A and B I read around 2.7V but I guess this is not representative since the voltage might peek during signals?

So, to help me not to fry my new MKR1000 :slight_smile: :
-Is this 14V an issue?
-Do I need the voltage divider?
-Is it safe to assume it is 5V now?

thanks!

Hi, Does the MKR1000 have a 485 port. You need to research RS485 to see that it is a current based system and that you need an inteeface IC to connect your Arduino to the 584 bus.

google arduino rs485

Tom... :)

Before I hook them up I wanted to be sure the RS485 levels are at 3.3V,

But they are not and never meant to be.
Read this RS485, RS232, RS422, RS423, Quick Reference Guide