Cbus not working

Discussion in 'General Discussion' started by jib, May 4, 2025.

  1. jib

    jib

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    I have c-bus version 1 . No light switches work they just flash when pressed. I have 57 points.
    I can’t scan via pci using toolkit.
    I have 4 power supplies and when disconnected and tested them individually….each read 36 volts.
    If I turn off all power supplies I read 9v on the network as I power up each power supply until I put the 4th power supply on - then I read 36 volts.
    Can anyone help me with what is going wrong?
     
    jib, May 4, 2025
    #1
  2. jib

    snuffles

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    When you say C-Bus 1,

    Are we talking Devices like relays and dimmers in Cream coloured Enclosures for controlling loads?

    Or something a little later, like

    Black Surface Mounted boxes

    Or Blue (Tiel) in Switchboard devices?

    Sorry, C-Bus 1 can mean many, as devices with C-Bus2 on the label were not exactly the 2nd models.

    If you have Images of wall plates with the commercial reference numbers (from the back) or any part numbers at all, that would help to define the age.

    When you press any key, do all keys even in different rooms flash, or just the one you pressed?

    Depending on the real age of your product, flashing, when buttons are pressed, can be.

    Fail to send, because no Clock
    Failed to send because the message was corrupted.
    From memory, there is also a low network voltage flash, but you report network voltage as being ok,

    If the power supply is good but you can not scan via PCI, and if you are having a clock issue, normally, Toolkit will try to enable the clock in the PCI for you. Still, you can try to do this manually, assuming that the PCI is showing as the only device that has scanned. Again, this depends on the age/model of your PCI

    But it would help to know the true age of the system and the model of PCI, etc..
     
    snuffles, May 4, 2025
    #2
  3. jib

    Trevor

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    Do you have a color touchscreen fitted...
     
    Trevor, May 5, 2025
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  4. jib

    NickD Moderator

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    The power supplies have current limiting, so with 57 points, you probably have a load of over 1A, but with only 3 of the power supplies you don't have enough supply, so they will all be current limiting and the output voltage drops. When you add the fourth there is enough current and they all return to their normal voltage.

    Having said that, they also have a current sharing mechanism which should mean that as soon as you load them, the voltage drops... which means you should only even measure 36V on a power supply when it is unloaded.. the fact that you statue the network voltage returns to 36V suggests this part of one (or more) of the power supplies may not be working correctly, which would also explain the loss of communications.

    Some more info about the model/age of the units you have would be helpful. but given the age of the system (sounds like it's well over 20 years), it's likely you may be up for some new power supplies.

    Nick
     
    NickD, May 14, 2025 at 1:14 AM
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