I need to monitor the outputs?????

Discussion in 'General Discussion' started by RT TT265, Mar 18, 2008.

  1. RT TT265

    RT TT265

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    Could someone please tell me the most cost effective way of monitoring the output channels, ie have the status symbol in schedule plus reflect the actual state of the channel not the group address if that makes sense.

    We were thinking of running separate ralays on the circuits connected to a bus coupler, if the circuit is on the relay would switch a separate address in the bus coupler.

    This would do except we are worried about the dimmers not switching the relay properly when turned off, leakage etc

    Any help much appreciated, :confused:
     
    RT TT265, Mar 18, 2008
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  2. RT TT265

    ICS-GS

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    Unless i am mistaken, bus couplers are only for input of information into c-bus, they are not capable of any output function, hence would not be able to operate the relay.

    Can you give a little more detail as to what you are trying to achieve.

    It sounds like you are concernerd with elecrcially isolating the circuit when the level is 0%? Why?

    Cheers

    Grant
     
    ICS-GS, Mar 18, 2008
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  3. RT TT265

    2SC

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    I think that the problem of RT TT265 is that when he activates an output channel, the schedule plus shows that the channel is activated however from some reason the output is not activated (e.g. a triped MCCB).

    If you intend to use bus couplers you have to use before a relay because the bus coupler is a dry contact and it will suffer from 220V. I believe that the in-between relay will not be activated by the small current of the dimmer when the dimmer channel is off. This is a quite expensive solution.
     
    2SC, Mar 18, 2008
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  4. RT TT265

    znelbok

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    Positive feedback that the channel is on/off.

    As it stands now, it is only an implied on/off/level.

    As you have indicated, a relay on the relay output units is not too hard to do and is achievable with a bus coupler. Dimmers, I don't know. You might be able to measure the output someway and convert it to a 0-10V or 4-20mA signal and get it back via a general input module. If you can indeed use a relay on the dimmer, at what level will it change state? This will probably be a different for each relay.

    Maybe Clipsal need a high integrity output unit that does it own output checking and feeds it back to the network as confirmation that the group is indeed at its desired state.

    Anyway you look at it, it is not going to be cheap. This type of feature has never been on the low cost side of things.

    What is the context of the problem, maybe we can help provide an alternative solution.


    Mick
     
    Last edited by a moderator: Mar 18, 2008
    znelbok, Mar 18, 2008
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  5. RT TT265

    RT TT265

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    Outputs

    Thanks Mick,

    The client is very specific on knowing what the output state is regardless of the indicators etc.

    I thought initially it could be software solution via reading the updated stautus of the units etc.

    Going down the relay to relay coupler path was viable, except the dimmer situation, there are current sensing relays but that would just blow the cost out.

    I was hoping someone had a cbus client that needed this level of information back from the system.

    :(
     
    RT TT265, Mar 18, 2008
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  6. RT TT265

    ashleigh Moderator

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    We have had some customers before who need to do this.

    If you do this, DO NOT USE A BUS COUPLER ON A MAINS CIRCUIT !!!

    Bus couplers are NOT isolated (they are at cbus potential) and are designed only for voltage-free low current contacts.

    If you must monitor the actual mains voltage being present on a circuit, I think you need to use the General Input Unit.
     
    ashleigh, Mar 18, 2008
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  7. RT TT265

    NickD Moderator

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    I think what he was suggesting is putting a (non-cbus) relay coil in parallel with the switched load, and putting bus coupler on the (voltage free) contacts of this extra relay.

    This should work fine but you'd need to make sure you maintain suitable isolation (suitable choice of relay and suitable segregation of wiring to the bus coupler). There may be other considerations depending on your local wiring rules.

    I'd be surprised if the leakage from a dimmer channel in the off state were enough to switch a relay coil.. it would depend somewhat on the particular relay. Also not sure how well the relay would work at lower dimming levels.. Try it and see!

    Nick
     
    NickD, Mar 18, 2008
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  8. RT TT265

    Don

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    C-Bus PRO series dimmers have the ability to measure load current on each channel. This information can be read by polling the unit with CAL commands.

    Not really elegant but might help in your situation.
     
    Don, Mar 19, 2008
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  9. RT TT265

    RT TT265

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    Outputs

    Thanks Nick, that was exactly what I was thinking, try it and see :)

    I may be getting worried about nothing, the leakage may not be enough to energise the relay.

    For clarification, If I was not clear, the idea was to have a CBus relay to switch a load and a standard relay, the contacts of the standard relay to switch the bus coupler. So no load through the bus coupler etc.

    It seems like alot of work, but if you say to a client you can do it, it is nice to know you can etc time to wire up some standard relays to a cbus dimmer and gauge the outcome :)
     
    RT TT265, Mar 19, 2008
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  10. RT TT265

    ICS-GS

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    Are you looking to do this to confirm electrical isolation to the client, or as an energy saving measure?

    Because the other obvious solution would be to have the dimmer output, feeding into a relay channel, the to the lamp, then set the turn-on/off threshold of the relay channel to 1-2%. (I.e. if relay OFF channel de-energized)

    But again this is not really a cheap option.

    Cheers

    Grant
     
    ICS-GS, Mar 19, 2008
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  11. RT TT265

    RT TT265

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    Outputs

    Thanks for the reply

    It is more of the client, say having a PC remotely located and wanting to know without a doubt (loss of comms etc) that when the Icon on the screen switches the circuit.

    The icon representing the status actually reflects the status of the output channel.

    I will experiment with a standard relay onto a CBus dimmer channel, bus coupler etc

    Pro series dimmers would possible work (not cost effective)

    CBus dimmer channel, CBus Relay Channel (same address), standard relay, bus coupler would work (but come on really not ideal :) )
     
    RT TT265, Mar 19, 2008
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  12. RT TT265

    RT TT265

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    Outputs

    Cheers

    I think ill take a look at Pro-series pricing and technology for querying outputs etc
     
    RT TT265, Mar 19, 2008
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  13. RT TT265

    muppets

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    Would probably do well to install the relays/contactors in an area where noise won't be a problem, at less than 50% the noise could be incredibly annoying.

    The other option would be to use a set/reset coil to eliminate hum, I know overseas there are contactor coils that are legal to mechanically latch for this reason - I tried to ask schneider for some about a year back but they said they didn't meet aust standards for import. However a set/reset coil as used in safety circuits for haulage winders would work ok, tough I couldn't tell you at what point they would switch.

    Best method for positive level feedback would be the general input module I would expect though expensive if you had lots of monitored outputs.
     
    muppets, Apr 30, 2008
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  14. RT TT265

    ICS-GS

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    you can get top mounted auxillaries mechanical latches for most brands of contactors, basically energise the 'normal' coil when required (as per normal), the mechanical latch holds the contactor closed, until the auxillary coil on the top is energised, then (as long as the poser is off the 'normal' coil) the contactor releases.

    You can also get latching relays, i know omron have them in aus.

    Cheers

    Grant
     
    ICS-GS, Apr 30, 2008
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  15. RT TT265

    Frank Mc Alinden

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    Hi Guys

    My guess is that the leakage from the dimmers will drive an ice cube relay..not sure about a contactor......

    I was thinking of monitoring the channel led status on the Dimmer/Relay unit might be a solution ???? I do this with some tv,s using my led probe

    HTH
    Frank
     
    Frank Mc Alinden, Apr 30, 2008
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