Using Sonar Plugins For Live Performance

Hi Folks!  I'm new here, so please forgive me if I don't do something correctly, or if this has been covered in the past and I missed it!
I use Sonar 8.5 a lot for typical studio tasks, connected to an Allen & Heath ZED R16, which I love.  This setup works great for recording tracks!  But I've also been trying to use Sonar plugins, like compressors and reverb, during live performances, by using the digital out from the R16 into a track in Sonar, with the output returned to a original channel on the R16.  I have Echo on in Sonar, which seems to be required to get the signal back to the R16.  But even with no plugins, there seems to be a noticeable delay or doubling of the signal; certainly not as clear as not routing through Sonar.  I've tried different Buffer sizes in Sonar and on the R16.
Has anyone been successful in using Sonar plugins during live performances, with nice clear signals?
 
Thank you all in advance for any advice!  In case it helps, here are some of the other settings I'm using:  Mic into Channel 1 on R16, Input on track in Sonar to Channel 1, Output on track in Sonar to Channel 1, Digital Return Pre Insert on the R16, Route Channel 1 to Left/Right main output on R16.