Hello,
Someone had asked a question about the Rebel Technology Open Sound Module. For connecting PD (and other things) to a modular synth
Latency is typically 15ms "round trip"; ie trigger into an Open Sound, going into another Open Sound, and out takes 15ms
http://www.rebeltech.org/products/open-sound-module/
I work for Rebel Tech and made this little video / tutorial about connecting PD to a modular synth with the Open Sound Module.
http://www.rebeltech.org/2016/06/pure-data-tutorial-3-open-sound-module/
Please forward any more questions I can help with.
Adam