Setting Up The Profinet Io Network - Omron CJ1W-PNT21 Operation Manual

Setting up the PROFINET IO network

3-4

Setting up the PROFINET IO network

3-4-1 Network structure
3-4-1-1 Line
20
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.
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.
Switch
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 network.
/i
Part Recommendation
Switch (optional) Industrial Ethernet Switch (either managed or unmanaged).
Figure 3.8: Ethernet line topology
Section 3-4