C-Bus Power Requirements

Adequate C-Bus Power Supply units must be installed or enabled to support the total consumption of all C-Bus devices connected to the C-Bus Network segment.

C-Bus Power Supplies are specially designed to share load when distributed around the C-Bus Network. To achieve this, the integrated C-Bus Power Supplies have an output impedance of approximately 32 Ω up to their maximum current of 200 mA. Once the maximum current is exceeded, the output impedance increases sharply to limit the current to a safe level in the event of a fault in the C-Bus Network wiring.

There must not be more than 2000 mA of total C-Bus Power Supply capacity enabled on a single C-Bus Network segment as this is the limit of the current carrying capacity of the C-Bus Network cable.

The dimmer unit includes a switchable inbuilt C-Bus Power Supply, which can supply up to 200 mA to the C-Bus Network when enabled. By default, the inbuilt Power Supply is disabled, but can be enabled (or disabled) via the front panel.

The SpaceLogic C-Bus Commission software provides you with information whether the inbuilt Power Supply is enabled or disabled in each unit, as well as a summary of the total network power capacity and consumption. This can be helpful in determining the Power Supply requirements of a particular network.

NOTE: The dimmers draw 20 mA from the C-Bus Network when main power is not connected or when the C-Bus Power Supply is not enabled.

Enabling/Disabling the C-Bus Power Supply from the Front Panel

The integrated C-Bus Power Supply can be enabled or disabled via the front panel by performing a short press on the top right channel button whilst holding down the top left channel button to toggle the enabled state. After the desired setting for the C-Bus Power Supply has been made, the function to change the setting from the front panel may be disabled via the SpaceLogic C-Bus Commission software to prevent further changes.

NOTE: Changing the Power Supply state will temporarily disrupt C-Bus Network communications, which can take several seconds to recover, depending on the network configuration.

The enabled status of the integrated C-Bus Power Supply is shown by the colour of the Unit Indicator.

Unit Indicator	Function
	C Bus Power Supply is enabled
	C Bus Power Supply is disabled

Refer Unit Indicator for more details.

The state of the network voltage is shown by the state of the C-Bus Indicator.

If the C-Bus Indicator is flashing or off, the network voltage is too low, meaning there is insufficient C-Bus power.
- In this case, additional power supplies may need to be enabled.
If the C-Bus Indicator is steady, the network voltage is sufficient.

The state of the C-Bus system clock is shown by the colour of the C-Bus Indicator.

C Bus Indicator

Function

(Green or Yellow)

C Bus clock signal has been detected

No C- Bus clock signal has been detected

Refer C-Bus Indicator for more details.

Enabling/Disabling C-Bus System Clock Generator from the Front Panel

A C-Bus clock signal is required to synchronize communication on the C-Bus Network. The dimmer unit (and most other C-Bus DIN Rail mounted devices) can be configured to generate the C-Bus system clock. It is recommended that the C-Bus system clock generator function be enabled in three units on each network segment.

If a C-Bus system clock is required on the dimmer unit, it can be enabled or disabled from the front panel by performing a short press on the top second-to-right channel button whilst holding down the top left channel button. This toggles the enabled state of the C-Bus system clock generator in the unit.

After the desired setting for the C-Bus system clock generator, the function to change the setting from the front panel may be disabled via the SpaceLogic C-Bus Commission software to prevent further changes.