User Manual Owner's manual

Rockwell Automation Publication 280E-UM001B-EN-P - July 2012 65
Introduction to EtherNet/IP and Device Level Ring Technology Chapter 3
EtherNet/IP General
Wiring Guideline
Ethernet is found in automation equipment, panels, and components. There are a
few guidelines, that if followed, will reduce the number of issues an EtherNet/IP
application may experience.
• Many EtherNet/IP applications will share the same space with power
conductors. If the Ethernet media must cross power conductors, do so at
right angles. This will reduce the coupling effect and reduce the potential
for communication noise.
• Where possible, route the Ethernet/IP media five feet or more from high
voltage sources (for example, lights, ballasts, motors, …) or sources of radio
frequency, such as variable frequency drives.
• Ensure that the application or equipment follows industry acceptable
grounding practices.
• Maintain media lengths between nodes to less than 100 m (328 ft). In
today’s environment it may be challenging to maintain these guidelines,
however these will reduce potential application issues.
Requested Packet
Interval (RPI)
The RPI is the update rate specified for a particular piece of data on the network.
This value specifies how often to produce the data for that device. For example, if
you specify an RPI of 50 ms, it means that every 50 ms the device should send
data to the controller or the controller should send data to the device. Use RPIs
only for devices that exchange data.