L5504D2U Dimming Behaviour

Hello,

I am a Lic Electrical Contractor, new to C-BUS.

My learning curve will involve the installers Course at some stage when time permits but in the meantime I am doing some self teaching with frequent referral to this forum. I am starting with some basic lighting but intend to open up the potential of C-Bus as I learn.

I have an L5504D2U (universal dimmer)
an 5500PCU (usb PC interface)
and a 5055DL (DLT wall switch)

I have the units wired on my test bench for now. Initial results were OK (save for a dodgy pink patch cord having to be diagnosed) everything functioning as per specs as a network so a load was introduced in the form of firstly 1 x SAL (Suni Lighting) LED downlight model no. S9041DL with Actec brand "Pluto" DIM350mA/12w driver. They are dimmable by trailing edge dimmers and have been running reliably on a Clipsal standard universal dimmer in a circuit of three units, although do not dim enough in that configuration

Used Learn to initially get it running and achieve simple on/off using the DLT fairly easily (sorry to be so basic). Dimming however has not been straight forward. The L5504D2U shows Orange for channel LED when used for simple on/off. When dimming attempted with the DLT, the lights do nothing for a second or so, then the channel LED flashes, then goes to green indicating leading edge and the light dims but is not reliable as further attempts to dim or brighten cause it to cycle off with the channel light remaining on orange or green.

I added the second and third downlight with similar results, then noted channel indicator on the dimmer flashing green/orange indicating short circuit cut out of channel. (I have confirmed twice no short exists in the wiring).

I went back to two lights and they again function on/off, with the dimmer showing orange (trailing). They then dimmed successfully although still going to green on channel LED (leading). After a short while they intermittently show channel led flashing orange (thermal overload of channel) and even red, which is not listed in my documents but can't be good so I have powered them off and resorted to this long message.

Lastly, the C-BUS network appears, in my very limited experience, to be functioning OK. I have the Toolkit software working on my PC, can make changes, toggle on/off, label the DLT etc. I have the clock enabled on the dimmer and the PC interface. The software burden is disabled on both items and I have a hardware burden in the interface socket. (So I can see it is there)

My questions/suspicions are:

I sort of suspect the lights are just not suitable but they were recommended by the Suni rep and my wholesaler as suitable for C-Bus. Does any reader have experience with them please?

Is there something I may be missing in the setup?

Many thanks for reading this far and in advance for any insight.

Cheers
Scott

 

Update

Quick update, sorry probably should have done this before posting, but a single 12v/50W halogen running through an osram redback functions normally on the same channel, dims in a smooth linear fashion 0-100%, obviously proving the C-Bus. Strangely though, channel led starts out Orange before turning green again when dimming. Works though!

Would still be interested in any comments on set up, although I realise this is pretty basic at this stage.

Looks like I'm back to the search for suitable LED options.

Thanks to anyone who has read and may have any thoughts, I am aware of the forum entries relating to LED's so will be revisiting them.

Cheers
Scott

 

Thanks Ashleigh, your post just beat my last in, many thanks for your interest, you are spot on.

Cheers,
Scott

 

1 led on channel

Hi Scott.
I have 1 led working fine on a dimmer at home in several places. I have found that putting a 414 in place of a 413 at the light point then plugging in a dummy iron core tranny works a treat. After changing to led we had loads or iron core trannys lying around so it could to put them to use.
We have tried the starburst 12w led with the best results and also elite 6watt gu10 work quite well. Apparently Clipsal will only warranty their product with their LED lights. I am yet to try clipsals new downlights after the monumental F*** up with their first lot of not so cbus compatible downlights!

 

An iron core transformer is not such a bad idea; it won't consume much power (couple of watts typically, though some can be quite lossy - I've measured one which drew 8W of real power with no load) compared with the purely resistive load you would need to satisfy a dimmer, and the inductive nature of the transformer could result in the dimmer operating in LE mode, which some LED drivers are designed for.
"Properly designed" LED drivers generally incorporate resistive or current loads that are applied at appropriate points in each mains cycle to provide the current needed to satisfy the dimmer's requirements. Usually a low impedance near the zero crossing, and a lighter load for the remainder of the cycle. These loads dissipate reasonable amount of power, so of course reduce the overall efficiency of the LED lamp.
If you use an iron core transformer together with a "properly designed" LED, you're probably wasting more power than you need to.

 

Update

Thanks all for the input.

Just by way of update, have 1 only Pierlite Starburst Eco (8w) downlight on the test setup now. It is working fine, through the dimming range running on TE mode on the Uni Dimmer. Only question marks are, it runs a little hot on full bright and have to wait for darkness to assess it's real world suitability in the intended application.

So far it seems a good but still affordable solution.

The cheapies sounded good when talked up by the rep but just didn't deliver under scrutiny.

Cheers,
Scott