Do I need to put a diode across the terminals of this opto based on the attached configuration (I have to switch from the high side!) ? I selected this opto thinking that it comes with a diode already between emitter and collector but have been loosely advised that it is just for EMC purposes, so would like to make sure of this. Please I need some advice and thanks in advance.

Name:  Screen Shot 2016-04-05 at 19.50.51.png
Views: 610
Size:  63.6 KB