Rockwell Automation 1786-series ControlNet Coax Media Planning and Installation Guide - Manual (Page 30)

30 Publication CNET-IN002B-EN-P - June 2010
Chapter 2 Plan a ControlNet Coax Media System
Determine Propagation
Delay The ControlNet maximum propagation delay specification refers to the worst
case signal delay between any two nodes on a network. You need to figure out
the worst case scenario based on distances and the number of repeaters
through which the signal has to travel.
Network delays include the delays through coax and fiber media, coax
repeaters, fiber repeater adapters and fiber modules.
In order for a network to operate, the sum of the network’s delays must be
equal to or less than the maximum propagation delay of 121 µs. The total
network allowable delay each way is 121 µs.
Listed below are delay values for ControlNet media.
For more information, see Chapter 2 in the ControlNet Fiber Media Planning
and Installation Guide, publication
CNET-IN001 .
ControlNet Media Items Delay Value
1786-RPCD 100 ns
1786-RPA 901 ns
1786-RPFS 94 ns
1786-RPFRL 100 ns
1786-RPFRXL 100 ns
1786-RPFM 153 ns
62.5/125 Micron fiber 5.01 ns/meter
200 Micron fiber 5.01 ns/meter
Coax cable 4.17 ns/meter
9/125 Micron fiber 5.01 ns/meter