Need help/advice on using NAC to communicate and control Fujitsu A/C's using BACnet

Discussion in 'C-Bus Automation Controllers' started by Lliam, Sep 15, 2020.

  1. Lliam

    Lliam

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    Hi to all the CBUS/NAC gurus

    Need help getting my head around what i need to do and what hardware is required to get a NAC talking to multiple Fujitsu A/C Units using BACnet.The area of BMS and BACnet is fairly foreign to me so my knowledge is limited.

    I have a number of apartments all with CBUS that will be connected back to the one 5500NAC. Lighting control will be provided on a wall mounted android tablet (one in each apartment).

    We have also been asked to provide control of the Fujitsu A/C Systems in each apartment to be displayed on the android tablets through the 5500NAC using BACnet.
    The HVAC contractors are installing a Fujitsu BACnet gateway (model: UTY-VBGX) for us to connect to for communication.

    So far i have not been able to confirm 100% (after much internet trawling) if what we are trying to do can be achieved with the current setup.

    I keep reading in the manuals/literature for the NAC that it can only run as a BACnet server (and not a client). Which makes me think that the NAC alone will not be able to send commands to the Fujitsu systems using BACnet and it can only recieve commands/requests from other BACnet clients. Once again though my understanding is limited and i may be wrong about what a BACnet server and client can do.

    Also alot of what I am reading is pointing to needing some kind of BMS controller and/or BACnet router hardware between the 5500NAC and the Fujitsu BACnet gateway to allow communication between the two systems.

    If anyone can help in explaining exactly what the NAC is capable of doing in regards to BACnet and if I am on the right track or on the the wrong track missing a big piece of the puzzle?

    Thanks
    Lliam
     
    Lliam, Sep 15, 2020
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  2. Lliam

    coppo

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    You're correct in all your assumptions.

    Unless the product has specfic function to act as a Client and a server simultaneously it will only work as either.
    In most cases the product wil lbe designed as either a Client or a Server.

    BACnet Client ( ie Headend or BMS) = SE automation Server typically and talks to single or multiple BACnet Servers.

    BACnet server ( 5500NAC, Mitsubishi A/C, panasonic A/C ), typically have the splits or devices (SE8000/iEM 3000 meter etc connected to them via proprietary cables and comms ( possibly some version of Modbus / profibus / etc... and "serve" these up to a BACnet Client.

    5500SHAC - only 50 "bacnet IP" points
    5500NAC - 500 "Bacnet IP" points

    for each device ...ie a split A/C you will need minimum 8 BACnet points, ( for typical control and monitoring you will need a point for each item. ie... the read/write point for selecting AC mode requires a seperate 'read only' point for you to display the current status of the "monitored value".

    ------------------

    BACnet Client on the 5500NAC:
    Schneider Electric EcoXperts- LRC with direct SE trading accounts are able to buy from SE national project services team a "customised 5500NAC" that will act as a very small scale "BACnet Client" to talk to BACnet servers.

    It does require a bit of Lua coding required by the installer still.

    ------------------

    you topology method:
    I don't think your topology model is going to work though as it means every apartment is going to have access to every other apartments C-Bus system and any faults that could appear will affect all of them., plus they all get aaccees to the same webserver as you are only using 1 x 5500NAC.


    -----------------

    You didnt state if the AC units are seperate Splits or a "shared VRF/VRF" model that supplies multiple apartments from 1 overall system with seperate temp and damper controls for each apartment.

    I'd suggest your simplest integration plan is to have 1 x 5500NAC ( standard mode as a BACnet server ) per apartment and have that talk back to a BMS (BACnet IP required) or other suitable BACnet client and program in your mapping relationships in the BMS from the other BACnet Servers to your C-Bus 5500NAC in each apartment.


    This would provide;
    - home owners don't have access to others areas, unless the BMS contractor programs it to be.
    - home owner can use their BYOD's to talk to their 5500NAC for local control of A/C and lighting
    - homeowner can see power consumption for their apartment, if the A/C BACnet server provides that detail and the BMS contractor provides the 'Read" value to their apartment.

    5500NAC won't support BACnet objects like schedules / multi-state values, but it works well for analog values and binary values.

    There's no actual security on a BACnet network, but it won't cause issues to others by having multiple apartments on the same C-Bus network and a signle 5500NAC.
     
    coppo, Sep 30, 2020
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  3. Lliam

    Lliam

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    Hi Coppo

    Thanks for your detailed reply. Things are getting clearer now.

    The fujitsu A/C' s will all be on one VRF network. There are only 11 apartments but not 100% sure at this stage how many indoor units there will be in each apartment (possibly upto 3).

    So basically your saying we need a BMS System that acts as a BACNet client that will allow control and/or monitoring commands that are intiated by the 5500NAC (a bacnet server) to be sent to and executed by the Fujitsu BACnet Gateway (another bacnet server).

    You mentioned the SE Automation Server can act as a BACnet client, is the device on following link the Automation Server you are talking about?:
    https://ecostruxure-building-help.se.com/topics/show.castle?id=8059&locale=en-US&productversion=3.2

    Are there other options avaliable we could use as the BACnet client that would achieve the same outcome? Like something software based? (we will have a permanent PC connected to the same network as the 5500nac and fujitsu gateway that would be avaliable).

    One thing I am still a bit confused about is how the 5500NAC can send these commands/requests out on BACNet if it can only be configured as a server. The BACNet section of the 5500NAC user manual only talks about selecting the EXPORT option of speific object values that I assume can then be seen by other BACnet clients.
    I suppose my question is how exactly do we program the 5500NAC to send a command though BACnet once we have set up a BMS BACnet Client to facilitate the communication between the servers?

    Thanks for you help.

    Lliam
     
    Lliam, Oct 8, 2020
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  4. Lliam

    notsomot

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    Hey Lliam,

    Over the coming weeks I’ll be doing the same setup. My setup is a VRV with 6 indoor units and a stand-alone unit using the same gateway.
    Have been told Fujitsu has someone to assist, but have my doubts with manufacturers and BMS systems
     
    notsomot, Oct 12, 2020
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  5. Lliam

    Krondor

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    if still relevant, there are easy solutions to interface Fujitsu's and C bus
     
    Krondor, Apr 23, 2021
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