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  • Up to 1000m of C-Bus Cat. 5 UTP cable may be connected to a single C-Bus network
  • Up to 100 C-Bus units may be connected to a single C-Bus network
  • Where more than 1km and/or 100 standard C-Bus units are required, two or more networks can be created and linked with C-Bus Network Bridge and/or C-Bus Ethernet Interface Units
  • Maximum number of networks in one installation is 255 (this limitation does not apply if a C-Bus Ethernet interface is utilised, the system size is then limited to IP addressing only)
  • Maximum number of networks connected in series to the local network via Network Bridges is seven (i.e. using six network bridges)
  • Each standard C-Bus unit requires 18mA @ 36V d.c. to operate correctly. Some C-Bus units, for example 5500PC, require 32mA. Some C-Bus units, for example L5508DIA, are self-powering and do not sink current from the 36V d.c. C-Bus network
  • More than one C-Bus power supply can be connected to a C-Bus network to provide sufficient power to the C-Bus units. The C-Bus power supplies will share the load evenly. Maximum total power supply allowed is 2,000mA (2A)
  • Any combination of power supply units is allowed as long as the total power available is 2,000mA or less
  • Each C-Bus network requires only one network burden. This network burden is software selectable on C-Bus output units
  • Each C-Bus network requires at least one system clock-generating unit (for data synchronisation)
  • C-Bus power supply units may be connected to different phases
  • Individual relay channels may be connected to different phases
  • On L5508D1A and L5504D2A units the mains supply to the units power supply and the mains supply to the output channels must be on the same phase
  • The isolation between the mains supply circuitry and the 36V d.c. C-Bus circuitry is greater than 3.75kV. This is achieved using double wound transformers and opto isolators. This means the C-Bus wiring, connections and circuitry can be considered extra low voltage
  • C-Bus Cat. 5 UTP cable has mains rated sheathing, which means the C-Bus cable can be taken inside electrical distribution boards, provided segregation requirements of local wiring standards are met
  • The following are control methods that provide a number of options when either manual or override control of electrical loads connected to a C-Bus network is required:
    Manual toggle of output channels using the manual override buttons on output units
    Remote ON/OFF override of a C-Bus network using standard 30 mechanism switches
    Auto remote ON override of a C-Bus network using the C-Bus Network Monitor (5500NMA)
  • All C-Bus output units consist of electronic components that may be damaged by surges, short circuits and over-voltages. All equipment should have over-current protection relevant to installed equipment and cable size and surge protection fitted.

Which Wires to Use
In order to maintain noise immunity, the natural twist between pairs must be retained when connecting to the positive and negative C-Bus terminals.
It is important that the following Cat-5 conductors are used when making C-Bus connections:

  • orange + blue for positive C-Bus Wires
  • orange & white + blue & white for negative C-Bus Wires