Lights on and off but no bus message

Discussion in 'C-Bus Wired Hardware' started by mann_rj, Jan 1, 2008.

  1. mann_rj

    mann_rj

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    Hi,

    I have a recently installed whole house CBus system.

    All is good, but two universal dimmer loads (same output unit) turn off then on when another relay unit has a load turned on.

    E.g. Laundry light (relay) is turned on, kitchen light (dimmer) goes off brieflt then comes back on.

    I have run Toolkit for a day to investigate the Application Log. There are no additional entries apart from the expected GA on and GA off messages.

    I am wondering where to go next. Is this surging or some sort of overload? It is not happening 100% of the time, and can happen when no other loads in the house are turned on.

    Thanks,
    Richard
     
    mann_rj, Jan 1, 2008
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  2. mann_rj

    NickD Moderator

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    It's possible that it is some kind of interference from the switching of the relay load.

    Can you tell us more about the loading (type/rating) on the Universal dimmer channels, and also on the relay channel(s?) that cause the glitch?

    Nick
     
    NickD, Jan 1, 2008
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  3. mann_rj

    mann_rj

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    Thanks Nick.

    One load that triggers the effect is a relay channel with three 12 volt electronic transformer (Osram) lights. One of the affected dimmer loads is two lights as above and one is seven.

    Another relay load that triggers the affect is also three 12 volt lights on the same transformers.

    A thought I have had is that the pink bus wiring is quite close the the dimmer module that is having the loads affected. Perhaps there is a data/power separation issue. i.e. Not separated enough!

    The electrician also used normal Cat5e patch cables (2 metres) to link up each of the four Cbus panels. I was not happy about this, and it could now be a cause of the problem.

    Richard
     
    Last edited by a moderator: Jan 1, 2008
    mann_rj, Jan 1, 2008
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  4. mann_rj

    NickD Moderator

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    The symptoms you describe don't *sound* like interference on the C-Bus cable... this would most likely manifest itself as all channels turning on/off, or poor reliability of bus communications.

    A few more questions...

    a) Are there loads on the other channels of the universal dimmer?
    b) If so, what type/rating are they, and are they affected in the same way?
    c) When the affected loads turn off.. do they always turn off together?
    d) When the affected loads turn off.. how long do they turn off for, and is this time consistent or does it vary?

    The use of normal Cat5e patch cables shouldn't affect normal operation, the difference between this and the pink C-Bus cable is in the voltage rating of the insulation... You may however be compromising the isolation of your installation from a safety point of view. It's possible though that your sparky took other precautions to maintain the isolation/segregation. If you are concerned, perhaps get a second opinion from another sparky (who knows C-Bus) next time you have one on site.

    Nick
     
    NickD, Jan 2, 2008
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  5. mann_rj

    mann_rj

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    The loads that are mainly affected are all on the one dimmer. They do not turn off together. Three channels are for kitchen lights (2, 4 and 7 downlights). The other channel is for dining lights.

    Lights go off for approx. 1 second. Seems very consistent, as though it gets a problem, resets and comes back up (although this is not the actual scenario probably).

    Problem is that only the kitchen lights are regularly on (two channels of four), so it may be a dimmer-wide effect that I am not seeing. I will try turning on all the dimmer outputs and see what happens and keep Toolkit running.
     
    Last edited by a moderator: Jan 2, 2008
    mann_rj, Jan 2, 2008
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  6. mann_rj

    wanricky

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    Software-wise, re-set the dimmer with toolkit and program it again from scratch. (Don't load from database) It doesn't seen to be the source of your problem, but it is good to do in order to make sure every little thing is programmed as expected.

    Electrically, if your other two channels are good, try swarpping the two affected with them and see if the same problem presists.

    If those lights are not from the same phase, it may be useful to list out the phase of them. When there is only one thin common neutral cable linking all these light and they have different phase input, switching on one of them may slightly affect those dimmer/tranformers at that instant. Anyway, you need an electrician with you to swarp either input or output one by one to check out electrical problem. :eek:
     
    wanricky, Jan 2, 2008
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  7. mann_rj

    mann_rj

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    Thanks for that. I am running three phases shared across the output units, so you could be going down the right path with that suggestion.
     
    mann_rj, Jan 2, 2008
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  8. mann_rj

    mann_rj

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    OK. I have reset the unit and reprogrammed. No effect. Even this morning, one load came off then on.

    Another load on the same dimmer (the two light one mentioned earlier) takes a few seconds to turn on sometimes. I am sure this is part of the same issue.

    So maybe messages are getting interference going to that dimmer?
     
    mann_rj, Jan 2, 2008
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  9. mann_rj

    NickD Moderator

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    The symptoms you described initially (loads that are ON turning OFF briefly without associated bus messages) do not sound like programming or communications errors to me.

    It sounds like the overcurrent protection in the output channel of the Universal Dimmer is being activated. This is one of the inbuilt protection mechanisms of that dimmer... if an overcurrent condition is detected, the output turns itself off. The firmware monitors this and will try to restart it, which in your case, it does successfully.

    In your case though, it sounds like the overcurrent protection is being tripped due to electrical transients generated by the nearby relay switching the capacitive input impedance of the electronic transformers. This can happen because the current path through the load and the output channel is a relatively low impedance. We have heard occasional reports of this and have replicated it in the lab.

    IF this is the case, the solution is to try and either remove or reduce the transient, or give it an alternative path.

    Seeing as you have a multi phase installation, it may be a simple matter for your electrician to move the relay channels that are switching capacitive loads (electronic transformers, compact fluorescent lamps, or normal fluorescents with power factor correction capacitors) onto a different phase to the Universal Dimmer, reducing the transients it is exposed to.

    Alternatively :
    - an inductor such as the 32EIND can be fitted in series with the capacitive loads, to reduce their inrush current and the resulting transient, or
    - fit a mains rated (X2 type) capacitor across the line and neutral terminals of the Universal Dimmer, to give a lower impedance path than the output channel itself.

    Unfortunately, ALL of these options require an electrician :(

    Nick
     
    NickD, Jan 3, 2008
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  10. mann_rj

    mann_rj

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    Thanks Nick.

    The house is brand new and the electrics are not 100% complete, therefore access to my sparky is no problem. I will get him to investigate and rectify.

    I appreciate everyone's input immensely. Cheers.
     
    mann_rj, Jan 3, 2008
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  11. mann_rj

    mann_rj

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    Just a follow up.

    I have noticed that all the affected loads are detected by the Universal Dimmer as Orange (trailing edge) whereas unaffected loads are all Green (leading edge) for the same Osram transformers and LV downlights.

    All the affected loads are in a single distribution board which contains two universal dimmers, an ethernet interface and a PACA.

    All downlight loads withing that board appear orange, whereas the reset of the house on the same hardware appears green.

    This looks to me like an indication of the problem.

    Any ideas?
     
    mann_rj, Jan 13, 2008
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  12. mann_rj

    NickD Moderator

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    Where you say the unaffected loads are shown as green.. are these connected to a universal dimmer as well?

    For a Universal Dimmer, trailing edge (orange) mode is the normal mode. Channels always start in this mode and for incandescent and electronic transformer LV lighting they should stay in this mode. A channel will only change over to leading edge (green) operation if it detects an inductive load (eg fans, iron core transformer LV lighting).

    Note that as far as the indicators are concerned, the unit remembers the last mode each channel was operating in (as long as the power is connected), so if a channel was operating in LE mode the last time it was turned on, the indicator will come on green as soon as that channel is turned on. If it happens to stay in TE mode, then indicator will change back to orange.

    If you have Universal Dimmer channels with only electronic transformer loads that are operating in leading edge mode, then there is something strange on *those* channels.

    It sounds like it might be time to give Tech Support a call.. we try to help out here as best we can, but Tech Support can spend more time and go through your exact setup in more detail than we can do here.

    Nick
     
    NickD, Jan 13, 2008
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  13. mann_rj

    mann_rj

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    No worries. Thanks for your your input Nick.
     
    mann_rj, Jan 14, 2008
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