Brief explanation of Clipsal C-bus system and its compatibility with dimmable LED lights

Nowadays, the “C-bus ” control  has been used widely for the HVAC and Lighting controls within commercial and residential buildings. Beside the convenience and effectiveness it brought, C-bus had also become one of the greatest headache for most of the electricians. As a lighting person, I have frequently encountered questions about C-bus from my clients. Thus I think it is it is worthy to share what I know about C-bus, and its compatibility with dimmable LED lights.

What is C-Bus

The “C-bus” system is a micro-processor-based control and management system for commercial and residential building, and it is patterned and owned by Clipsal® Australia.Be ware, it is not a dimming protocol.

This system can be used to control lighting and a wide range of other electrical devices, such as motor, pump and audio visual devices. For lighting, in particular, it can be able to manage from a simple ON/OFF control for a lighting circuit, to as complex as dimming a particular light accompany with sensors[1]. For a better understanding, please refer to chart 1, which is the simple flow chart for a typical C-bus system:

 C-bus flow chat 2

Chart 1: C-bus network flow-chart

(For more information, please refer to the C-bus Training manuals[2]. Special thanks for Ian Booker from Clipsal® technical support).

 Is my dimmable LED compatible with C-bus?

To find out the answer of this question, in my experience, there are two other things that need to be clarified:

1.    How my LED light is be dimmed?

Without doubt, this is the first thing you have to know. In the Australian market, most of the LED lights are power by electronic drivers, which means that they can be dimmed by trailing edge or universal dimmers. While for retrofit LED fixtures (for example some of the LED MR16 light bulbs), leading edge dimmers can be suitable as well. Of course, there are still lots of other different types of dimmable LEDs, you can always find my previous article “How to choose a dimmable LED?” for more information. Anyway, please ask your lighting supplier if you are not sure about it.

2.     Is my C-bus system on a dimmer?

Although it seems like a foolish question, the fact is, the reason of some problems regarding to C-bus dimming, is the system is not even on a dimmer. Regarding to this problem, there are basically two ways to find out if there is a dimmer in the system:

To begin with the most straightforward way, according to Ian Booker from Clipsal® technical support, you can always install a normal halogen lamp onto one of your C-bus output terminal, and try to dim it via your control interface. If the lamp can be dimmed, it means that the system is on a dimmer, and the way to fix the problem is either changing the correct LED light, or to change your C-bus dimmer unit. Otherwise, if the light cannot be dimmed, then it is no doubt that the system is not on a dimmer.

Moreover, there is also a not-that-easy way, which is, check through the PC interface. As a control network, the entire C-bus system is controlled through the network bridge, and it can be programmed and inspected through the PC interface. All you need, is to connect it to a laptop with the “C-bus toolkit” software installed. This software is a free application that can be downloaded from the Clipsal technical support website[3]. Through this software, you can easily find out if a dimmer is installed within the system network. However, it is strongly advised that you should find a licensed technician to do this job for you, at an incorrect programming may exert potential risks.

3.   Is my dimmable LED matches my C-bus dimmer ?

OK, if you have a clear idea of the dimming protocol of your Led light, and sure that you C-bus system is on a dimmer, it is time to figure out if your LED and your system matches with each other. To sort this out, in my experience, you can find out the part number of your C-bus dimmer, and figure out what protocol it is under. Table 2-1 to 2-3 in the Appendix section illustrate the part number and the dimming protocol for all the conventional C-bus dimmers, hope it can be a reference while you checking your C-bus dimmer. They are:

  • Table 2-1 : High power dimmer
  • Table 2-2: Analogue dimmers (Din-Rail and 0-10V )
  • Table 2-3: Digital dimmers (DSI, DALI and DMX)

Summary

Frankly speaking, although C-bus system has sometimes given us a great amount of trouble, if you can spend some time on it, it will eventually become an effective tool that make your life more convenient and colourful.

Appendix:

Part number Name Dimming Protocol No. of Channel Current Rating
L5112D10UAR6 L5112D Range 12 channel Infinity Architectural Dimmer All dimming protocol 12 40A 3 phase
L5112D5UAR6 L5112D Range 12 channel Infinity Architectural Dimmer All dimming protocol 12 20A 3 phase
L5106D20UAR6 L5106D Range 6 Channel  Infinity Architectural Dimmers All dimming protocol 6 40 A, 3 Phase
L5106D16UAR6 L5106D Range 6 Channel  Infinity Architectural Dimmers All dimming protocol 6 32 A, 3 Phase
L5106D10UAR3 L5106D Range 6 Channel  Infinity Architectural Dimmers All dimming protocol 6 20 A, 3 Phase
L5106D5UAR3 L5106D Range 6 Channel  Infinity Architectural Dimmers All dimming protocol 6 10 A, 3 Phase
L5103D20UAR1 L5103D Range 3 Channel Infinity Architectural Dimmers All dimming protocol 3 20 A, 3 Phase
L5103D16UAR1 L5103D Range 3 Channel Infinity Architectural Dimmers All dimming protocol 3 16 A, 3 Phase
L5103D10UAR1 L5103D Range 3 Channel Infinity Architectural Dimmers All dimming protocol 3 10 A, 3 Phase
L5103D5UAR1 L5103D Range 3 Channel Infinity Architectural Dimmers All dimming protocol 3 5 A, 3 Phase
L5112D20LP L5112D Range 12 Channel Professional Dimmers All dimming protocol 12 60 A, 3 Phase
L5112D16LP L5112D Range 12 Channel Professional Dimmers All dimming protocol 12 60 A, 3 Phase
L5112D10LP L5112D Range 12 Channel Professional Dimmers All dimming protocol 12 40 A, 3 Phase
L5112D5LP L5112D Range 12 Channel Professional Dimmers All dimming protocol 12 20 A, 3 Phase
L5112D3LP L5112D Range 12 Channel Professional Dimmers All dimming protocol 12 36 A, 1 Phase; 18 A, 2 Phase
L5106D20LP L5106D Range 6 Channel Professional Dimmers All dimming protocol 6 40A 3 phase
L5106D10LP L5106D Range 6 Channel Professional Dimmers All dimming protocol 6 20 A, 3 Phase
L5106D5LP L5106D Range 6 Channel Professional Dimmers All dimming protocol 6 30 A, 1 Phase; 10 A, 3 Phase
L5106D3LP L5106D Range 6 Channel Professional Dimmers All dimming protocol 6 20A , 1 phase
L5103D20LP L5103D Range 3 Channel Professional Dimmers All dimming protocol 3 20 A, 3 Phase
L5103D10LP L5103D Range 3 Channel Professional Dimmers All dimming protocol 3 30 A, 1 Phase ; 10 A, 3 Phase
L5103D5LP L5103D Range 3 Channel Professional Dimmers All dimming protocol 3 15 A, 1 Phase

Table 2-1Clipsal C-bus high power dimmers

Part number Name Dimming Protocal No. of Channel Current Rating
L5504D2U 4 Channel Universal Dimmer with Power Supply Universal 4 2A
L5504D2UP 4 Channel Universal Dimmer Universal 4 2A
L5504D2A 4 Channel Dimmer with Power Supply Leading edge 4 2A
L5504D2AP 4 Channel Dimmer  Leading edge 4 2A
L5508D1A 8 Channel Dimmer with Power Supply Leading edge 8 1A
L5508D1AP 8 Channel Dimmer Leading edge 8 1A
L5504AMP 0-10V Analogue Output Unit  0-10V 4 25mA

Table 2-2 Clipsal C-bus Analogue dimmers

 

Part number Name Dimming Protocal No. of Channel Current Rating
 L5508DSI 8 Channel DSI Gateway with Power Supply DSI 8 200mA
L5508DSIP 8 Channel DSI Gateway DSI 8 18mA
5502DAL 2 Channel DALI Gateway for C-Bus DALI 2 32mA
5500DMX C-Bus DMX Gateway DMX 1 for 40 units 50mA

Table 2-3 Clipsal C-bus Digital dimmers

[1] http://www2.clipsal.com/cis/technical/product_groups/cbus

[2]  http://www2.clipsal.com/cis/technical/technical_support/training2/cbus_control_and_management_system/basic

[3] http://www2.clipsal.com/cis/technical/downloads/c-bus_toolkit

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