Safety Modules Owner manual
80 Rockwell Automation Publication 1791ES-UM001D-EN-P - May 2013
Appendix A Get Diagnostic Status from Modules by Using Explicit Messaging
From the top of the Message Configuration dialog box, click Tag to see
this dialog box.
When the explicit message reads the data from the 1791ES-IB16 module,
the data appears in the MSGdata tags as shown.