Expanding Your System
You can daisy-chain your system starting from each node connected to the switch. The host
communicates directly with all the nodes in one chain through one bus line. A standard
Ethernet device or switch can be added to the end of the chain if desired and used as normal.
Be aware that these devices will compete for network bandwidth with the controller. Reliable
system design requires awareness of the bandwidth consumed by each device during
operations. This topology offers no redundant links.
Figure 7. Expanded Topology
Node
Node
Node
Host
Node
Node
Node
Node
Node
Node
cRIO-9805
Advantages:
•
Simple and inexpensive installation, expansion, and troubleshooting.
•
Ideal for low number of nodes. NI recommends a maximum of 15 nodes per chain.
•
No additional switch needed.
•
Can cover long distances.
Disadvantages:
•
Any unpowered nodes and/or node failure disrupts network communication.
•
Addition or removal of any node disrupts network communication.
•
Failure of any Ethernet cable and/or improper cable termination disrupts network
communication.
•
Network performance and synchronization affected when node count exceeds 15 per
chain.
Adding Redundancy
To add redundancy, you can connect an additional Ethernet cable to the last node of a daisy
chain and reconnect that cable back to the switch. In this topology, the host communicates
with all nodes through the most effective path. You must configure the network properly
before creating redundant links in the network.
cRIO-9805 Getting Started Guide
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© National Instruments
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