CBUS DALI Gateway Ramp Issues

Discussion in 'C-Bus Wired Hardware' started by remedy, Feb 20, 2014.

  1. remedy


    Nov 22, 2008
    Likes Received:

    I have an installation at the moment with CBUS DALI Gateways controlling GE DALI LED Fittings. We have a MK11 touchscreen with LOGIC sending out commands which instruct the gateways to DIM over a set ramp time to a level.

    We are using the DALI Broadcast address and have changed the DALI application to lighting and mapped a lighting group address to the DALI Broadcast address.

    We have done numerous jobs in this way with these fittings without an issue. However the LED Driver has now changed from a Phillips Xitanium to a GE ballast.

    The problem we are having is that when you select match CBUS ramp rates to DALI ramp rates in the gateway. The ballasts will not respond. When you take this option out the ballasts respond to DALI ramp rates and FADe at different response times but eventually get to the level sent.

    We have broken the network down to 1 gateway and we get the same response. I have checked the cbus network to see that the messages are being sent and they are.

    The only other bit of info I can give to help is that when we interrogated the ballasts with TRIDONIC DALI software we get a Referencing Fault and this is on every ballast.

    remedy, Feb 20, 2014
  2. remedy

    ashleigh Moderator

    Aug 4, 2004
    Likes Received:
    Adelaide, South Australia
    I hate to bring bad news, but it sounds like the ballasts are dodgy.

    Two factors suggest this:

    1. Setting to match fade rate to cbus (as you did) simply causes the gateway to issue a command on DALI to set the fade time to an equivalent to a cbus ramp rate. Provided you don't use very long cbus ramps (as the max fade time in DALI is something like 90 seconds) this will be OK. However when you do this, the ballasts no longer respond to a SUBSEQUENT command to perform a fade.

    2. A failure to respond to Tridonic software.

    #1 suggests the ballasts are not tolerant to the reprogramming command; and are either having a reset, rebooting, or something else a bit odd following the setting of the fade time.

    #2 is more of a concern because the Tridonic s/w does not do anything very magical, it just issues plain ole commands. If it can't talk to the ballast then this suggests it is not properly DALI compliant.

    I presume for #2 that you used a Tridonic interface device such as an SCI2, or similar, so that you can eliminate the interface device as a possible source of trouble. (If not, you should, there are a number of devices out there that emulate an SCI2 - but how well they do this is anybodies guess).

    You probably need to be talking to your GE sales rep.
    ashleigh, Feb 21, 2014
  3. remedy


    Aug 1, 2013
    Likes Received:
    I agree with Ashleigh that the ballasts sounds suspicious and the most likely culprit.

    The CBus sets the fade rate in the DALI ballast which instructs it to dim smoothly, and the smoothness of fading is then dependent on the DALI ballast.

    Below are two articals on my blog explains it in more detail, both these settings affect the smoothness of the DALI dimming;

    DALI FadeTime is considered with DALI Scene and Arc Power Level commands
    DALI FadeRate is considered with DALI Up and DALI Down commands (e.g. usually press and hold with a switch).

    If you send me the specs on the DALI LED driver and light, (i.e. mA usage and Wattage) I can provide you an alternative Tridonic ballast that "should" work. I say "should" because there are no guarantees with LED, even with a matching driver. As there are no official standards you can only know by trial and error. Fill out this form on our DALI Lighting Project Assistance Page if you require assistance.
    Last edited by a moderator: Feb 26, 2014
    jaied, Feb 26, 2014
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