Skip navigation


Currently Being Moderated

RS-485 Loopback (Port to Port) Test 2 Wire AUTO MODE ONLY

VERSION 4  Click to view document history
Created on: Apr 3, 2009 8:39 AM by tyler-c - Last Modified:  Oct 4, 2013 10:40 AM by tyler-c


Programmatically configure loopback test.

Functional Description

In order to perform a RS-485 two wire loopback in AUTO mode, you need to have two separate ports to communicate between.  In this example, the two wire AUTO mode is programmatically set on both ports.  The important part is the connection made between the two ports.  Make sure to tie pins 4 and 8 (RXD+ and TXD+) together then wire this connection to pins 5 and 9 (RXD- and TXD-), which should also be tied together.  This is refelected in the next two images.



Requires LabVIEW 8.0 or higher and the NI-VISA drivers.


db9.jpgRS485 2 Wire AUTO connection.jpg


485 Loopback Test 2 Wire Auto_LV8.0_FP.jpg

485 Loopback Test 2 Wire Auto_LV86.jpg

Comments (5)