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CFLink Bus Physical Specs

CFLink is an RS485, 5-wire bus, used to interconnect CommandFusion hardware to create a CFLink network.
It is a peer-to-peer bus, where all devices can talk directly to each other. There is no master-slave devices, all devices are equal priority.


CFLink uses 5 wires as follows:

  1. Isolated Ground
  2. Data +
  3. Data -
  4. Power (9-30V DC)
  5. Ground

The reason there are two grounds is to reduce noise interference and ground loops by isolating all data communication from the power supply.
The CFLink data is isolated even at board level to ensure high quality data integrity.

Any 5-core or greater cable can be used, including CAT5/6.

For CAT5/6, we recommend that two cores be used for Power and two for ground, then one core for each data and isolated ground (using a total of 7 cores).
This is to reduce the resistance in the power wiring.

For CFLink cabling diagrams, best practices and a power calculator, see this page.

Benefits Over Ethernet

  • Longer runs - CFLink can run for over 1km without the need for repeaters.
  • Multiple wiring topologies - CFLink can be daisy chained, home run, star, or any combination of topologies.
  • Less overheads costs - Expensive networking hardware such as ethernet switches are not required, which is a significant cost in larger automation networks.
  • Fewer points of failure - The CFLink bus is not reliant on a single device to handle communication routing (see Peer to Peer details below), unlike Ethernet which can have many points of failure at routers, switches, etc.
  • Simplified setup maintenance - A network administrator is not required to handle IP address ranges, conflicts, etc. CFLink ID conflicts can be automatically resolved via System Commander software.
  • Separated from corporate networks - access to tightly controlled corporate networks is not required, meeting requirements for data security in corporate environments.
  • Lower unit price - The final cost to customers is significantly reduced by removing the need for Ethernet stacks physically from the product and from firmware R&D costs.
  • Can use any 5 core or higher cable, including CAT5/6, making it more install-friendly. Only 3 cores are required for data when local power is used at each end of the cable run.

Peer to Peer Benefits

CFLink is a peer-to-peer (P2P) bus, which means every device on the network can communicate to any other device.
Whereas a master-slave bus requires a master device to handle all communication to slave devices.

P2P is beneficial in automation for the following reasons:

  • The system is not dependant on a single device to operate. In master-slave, if the master device fails for some reason, then the whole network goes down.
  • P2P bus on the other hand will continue to operate if any device fails.
  • The burden of processing all messages is not placed on a single device. All devices are smart enough to communicate with each other directly.
  • The devices are more affordable due to lower processing requirements of distributed intelligence.
hardware/cflink/cflink-bus.txt · Last modified: 2014/01/20 02:15 by aaron