Design Considerations Reference Manual User guide

Rockwell Automation Publication ENET-RM002C-EN-P - May 2013 89
Predict System Performance Chapter 5
Estimate Maximum Input or Output Times for CIP Connections
System response is dependent on several factors. These are the dominant factors:
• RPI value
• Number of implicit CIP connections.
To simplify, the response time of a connection can be approximated with only
the RPI.
The maximum input (I/O to controller) or output (controller to I/O) times for
implicit CIP connections can be estimated as follows:
• Rack-optimized: 1 RPI
• Direct Connect:
– Digital = 1 RPI
– Analog (nonisolated) = 2 RTS (Real Time Sampling rate)
– Analog (isolated) = 1 RTS
• Produced/Consumed Tag = 1 RPI
The above response times are estimates. For more accurate numbers, include
system delays, as described in Refine Estimates
on page 99.