user55214: I am trying to build communication across multiple Arduino using RS485. When i am trying to connect 3 Arudino nano together using breadboard my code doesn't reach slave where as if i just if i do direct connection between 2 RS485 without breadboard it works but i use breadboard for 2 it doesn't work. Am i missing any setup here?
Breadboard connection - A & B are connected to + & - of both RS485.
Working connection - A & B of first RS485 connected to A & B of 2nd RS485.


user20245: It is possible you have too many resistors on the RS485 bus. From the RS485 wikipedia page there is this quote:  

Ideally, the two ends of the cable will have a termination resistor
  connected across the two wires.

This may explain why you can use 2 of your RS485 interfaces but not 3.  Consider removing the resistors from the RS485 board in the middle if possible.

55214: <p>I am trying to build communication across multiple Arduino using RS485. When i am trying to connect 3 Arudino nano together using breadboard my code doesn't reach slave where as if i just if i do direct connection between 2 RS485 without breadboard it works but i use breadboard for 2 it doesn't work. Am i missing any setup here?</p>

<p>Breadboard connection - A &amp; B are connected to + &amp; - of both RS485.</p>

<p>Working connection - A &amp; B of first RS485 connected to A &amp; B of 2nd RS485.</p>

<p><a href="https://i.stack.imgur.com/N4Gzw.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/N4Gzw.png" alt="enter image description here"></a></p>
 20245: <p>It is possible you have too many resistors on the RS485 bus. From the <a href="https://en.wikipedia.org/wiki/RS-485" rel="nofollow noreferrer">RS485 wikipedia page</a> there is this quote:  </p>

<blockquote>
  <p>Ideally, the two ends of the cable will have a termination resistor
  connected across the two wires.</p>
</blockquote>

<p>This may explain why you can use 2 of your RS485 interfaces but not 3.  Consider removing the resistors from the RS485 board in the middle if possible.</p>
