Network Installation - Omron CJ1W-PNT21 Operation Manuals

2 Nomenclature and Installation
2-3

Network Installation

A PROFINET IO network can be setup as a line, star, tree or ring network. When using the CJ1W-
PNT21 unit in any of these networks, the following precautions apply:
• Always be aware that any additional Ethernet communication through the PROFINET network
may influence the PROFINET IO Communication.
• It is recommended to physically separate the PROFINET IO network from other Ethernet-based
communication networks (e.g. IT infrastructure) to assure reliable I/O data exchange.
• Severely overloading the CJ1W-PNT21 with data traffic may cause the Unit to temporarily block
the Ethernet port, interrupting all traffic including PROFINET IO communication.
Line Network
A line topology comprises multiple IO Devices connected in series. Many IO Devices, such as the
Omron GRT1-PNT IO Device Unit have an Ethernet switch integrated in the Unit offering an easy way
to interconnect all Devices.
 Advantages of the Line Topology
• In most control systems, the line topology requires the lowest cabling effort.
• A line topology resembles a traditional field bus structure (comparable e.g. to PROFIBUS-DP).
• A basic system can be built without additional Ethernet switches.
 Disadvantages of the Line Topology
• Communication paths through many switches affect transmission times.
• A malfunction or power disruption of a single device will result in disconnection of part of the net-
work.
Additional Information
The switch shown above (optional) should be of an Industrial Ethernet Switch type (either man-
aged or unmanaged)
2-10 CJ-series PROFINET IO Controller Unit Operation Manual for NJ-series CPU Unit (W511)