Rockwell Automation Publication 1791ES-UM001G-EN-P - November 2016 131
Get Diagnostic Status from Modules by Using Explicit Messaging Appendix A
The first 32 bits of the instance are in IB8XOB8MSGdata[0].0…31, 
and the final 8 bits are in IB8XOB8MSGdata[1].0…7. Map these 40 
bits according to Instance 852. An easy method to do this mapping is to 
create a user-defined tag (UDT) for Instance 852. Once complete, it 
appears as shown in Figure 65
.
Figure 65 - Instance 852 UDT