Universal Dimmer Issues

Discussion in 'General Discussion' started by frantic, Feb 29, 2012.

  1. frantic

    frantic

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    Hi all I haven't posted for a few years, I used to post under the name Kelly but forgot my password details etc so I have re registered under Frantic.
    The issue I am having is with Universal dimmers and channels turning OFF and then turning back ON again.
    It is a new house that I commissioned mid 2011 and has 6 universal dimmers installed. It is dimming 50W dicroic lamps only. The Electrician that wired the job did a good job and wired the house to normal wiring practices. He ran out a circuit from the switchboard looping the Earth and Neutral conductors to each fitting including ceiling sweep fans on CBus fan control relays on the circuit and ran a single active back to the enclosure with the Universal Dimmers.
    The client has reported and I have seen it once myself that some of the lighting channels will turn themselves OFF and then back ON instantaneously. It is not always the same channel and they cannot pick a trigger that will make this fault happen. It usually happens at least once a day.
    I set up a log on the touchscreen and asked them to check it when it happened but the log doesn't pick it up.
    Its fair to say they are not happy. I have had my project checked by CIS and they could see no problems.
    The response I have had from Tech Support and they have been helpful is It
    has been suggested that their could be a common neutral on the loads that
    is causing the universal dimmers to think they need to change between
    trailing or leading edge.
    If the loads on the dimmers and relays etc share
    a common neutral between them, if say a couple of channels are active on a
    universal dimmer and then another channel on a relay is turned on, if
    sharing a common neutral there is a voltage change/difference detected by
    the other universal dimmer that may trick it into thinking that it needs to
    change it's state of leading or trailing which would result in the loads
    turning off then on.

    Has anyone experienced this issue and have you any suggestions in rectifying the fault..

    Thanks Mark
     
    frantic, Feb 29, 2012
    #1
  2. frantic

    tobex

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    I have some additional ideas on what to check. Just thinking out of the box.

    - What is the temp of the area where the dimmers live. Does it get really hot there ?

    - Have you exceeded any loading limits ? 2A ?

    - What about the Cat5 cable ? Is there any chance one of the cables between the units is in some way fault, loose or unlucky dud. When some units lose network they can do the whole reset thing.

    - What is your network voltage on the CBUS network ?

    - Are you using Overvoltage protection on the Units ?

    - Is there any RCD on the lighting power ?

    - What is the situation with clock and burden ? Maybe you have too many clocks or too many burdens.

    - When the dimmer unit resets do the wall switches flash ?

    - Does it happen when it rains ?

    I personally think it is a good idea to isolate systems. I keep my dimmers on a different circuit to my relays.

    You could also have a bad joint in the wiring management. That can make a tiny arcing and cause a voltage ripple which upsets the dimmer. I recommend a good wiring management system such as the WAGO blocks because they have a high density and give a strong reliable connection very easily.
     
    tobex, Feb 29, 2012
    #2
  3. frantic

    NickD Moderator

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    These symptoms sound like the overcurrent protection of the dimmer kicking in... there are probably a couple of other threads that cover this.. i found one here.

    Tech support should be aware of this problem and should be able to advise you of a workaround.

    Nick
     
    NickD, Feb 29, 2012
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  4. frantic

    frantic

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    Thanks for your detailed reply I will answer your question below
    I have some additional ideas on what to check. Just thinking out of the box.

    - What is the temp of the area where the dimmers live. Does it get really hot there ?
    Not a hot area. Under a stairwell in large switchboard enclosures.

    - Have you exceeded any loading limits ? 2A ?
    No most channels have a max of 6 50w lamps.

    - What about the Cat5 cable ? Is there any chance one of the cables between the units is in some way fault, loose or unlucky dud. When some units lose network they can do the whole reset thing.
    Possible but haven't had any issues in commissioning job or follow up visit.

    - What is your network voltage on the CBUS network ?
    All good minimum 26V accrooss job
    - Are you using Overvoltage protection on the Units ?
    No

    - Is there any RCD on the lighting power ?
    yes

    - What is the situation with clock and burden ? Maybe you have too many clocks or too many burdens.
    2 Clocks and I actually installed a hardware burden on followup visit and same result reported

    - When the dimmer unit resets do the wall switches flash ?
    Haven't had this reported to me and fault happens regularly so I would say No

    - Does it happen when it rains ?
    No all year round

    I personally think it is a good idea to isolate systems. I keep my dimmers on a different circuit to my relays.

    You could also have a bad joint in the wiring management. That can make a tiny arcing and cause a voltage ripple which upsets the dimmer. I recommend a good wiring management system such as the WAGO blocks because they have a high density and give a strong reliable connection very easily.
     
    frantic, Mar 4, 2012
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  5. frantic

    frantic

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    Thanks Nick tech support didnt go down this line at all.
    They were of the opinion that the neutral was the issue.
    I haven't been back to the site for 6 months and they are still experiencing the same fault.
    Over current protection would only kick in when 2.5 amps is exceeded and the most I have on a channel is 300W
    Cheers Mark
     
    frantic, Mar 4, 2012
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  6. frantic

    tobex

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    Is there anyone from technical who can give feedback on having 2 clocks. I only ever use one myself.

    If the unit which goes on the fritz is also supplying the burden and clock then it will take down the whole network.

    The reset condition (what the unit does after it loses power or what it does when it loses network) is stored in the unit. Maybe you can tell us what those settings are. Losing network will trigger the stored condition on what to do when it is isolated.

    I personally would check all of the connections, cables, burdens and clocks. I know it is really easy to have too many clocks and too many burdens. But I need to confirm that with the technical people. Maybe they can comment on this.
     
    tobex, Mar 4, 2012
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  7. frantic

    Newman

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    The official recommendation from Clipsal is to have 3 units with their Clock generator enabled and only 1 burden on the network, either the plug-in burden or a software-selectable one. Note that enabling the clock generator on multiple units in Toolkit does not make that unit start generating the network clock, as only 1 unit will be doing this at any given time. There is a difference between the clock being enabled and the clock being active. You need to check the status tab of the units to discover which unit is actively generating the network clock.

    A couple posts here and here with more info.
     
    Last edited by a moderator: Mar 4, 2012
    Newman, Mar 4, 2012
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  8. frantic

    NickD Moderator

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    Hi Mark,

    If you read that link carefully, the problem I was referring to was not with the loading on the channel, it's when there is some kind of transient, perhaps due to some large load switching nearby. If this creates a spike on the line, the lowest impedance path is often through the load, which creates a high peak current, which the dimmer detects and shuts itself off temporarily and restarts.

    Tech Support should be aware of this and be able to advise you on a work around.

    Nick
     
    NickD, Mar 5, 2012
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  9. frantic

    frantic

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    Thanks Nick and Tobex I will follow up with tech support again. The last time I spoke to them the only solution they offered me was to put a capacitor on each channel. It is happening over multiple dimmers and the caps trade price was around $40 each so I didnt take it any further. Have you possibly heard of a possible work around.

    Thanks again for the advice,
    Mark
     
    frantic, Mar 6, 2012
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  10. frantic

    NickD Moderator

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    Hi Mark,

    The workaround does involve putting an appropriate capacitor across the channel (or finding and eliminating the source of the noise).

    I see what you mean about the price of the 31CAP... I nearly fell over.

    The purpose of the capacitor is to provide a path for the transient (noise) that is a lower impedance than the on-state of the load+dimmer channel.

    You probably don't actually need one on each channel, this is just the shotgun approach that requires little thought about placement. Depending on how the wiring is done, you may be able to solve the problem with a single, more strategically placed capacitor, but you'll need to look at how the active is distributed to the channel loads, and the return path in order to determine the best place to fit it.

    Nick
     
    NickD, Mar 6, 2012
    #10
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