Rockwell Automation 1756-DHRIO_DHRIOXT ControlLogix Data Highway Plus-Remote I/O Communication Interface Module - Manual (Page 169)

Rockwell Automation Publication 1756-UM514C-EN-P - June 2014 169
Application Guidelines and Tips Appendix B
DH+ Baud Rate Comparison The following figure shows an example where a ControlLogix controller sends
messages to a PLC-5 via a 1756-DHRIO or 1756-DHRIOXT module.
Performance differences exist if the connections are cached or uncached.
Use Cached Connections
The following figure illustrates the difference in messages per second available
with cached connections for each DH+ baud rate.
1756-DHRIO
PLC-5/60 processor
DH+ Link
41284
ControlLogix Controller
0
50
Number of Nodes (that is number of messages)
1 2 3 4 5 6 7 8 9 10 11 12 13
100
150
200
230K
115K
57.6K
14 15
250
300
Messages per Second