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  1. #1
    Join Date
    Feb 2007
    Posts
    6

    Lonworks connectivity

    I am leading a student team that is installing a sophisticated HVAC system into a solar powered house. The house is an entry into the Department of Energy's Solar Decathlon. We are controlling a mini-split HVAC system with separate ERV and de-humidification. We will also be controlling the PV array, lighting, domestic (solar) hot water system, through the network.

    The devices that we are controlling speak Modbus-RTU, BacNet, and Lonworks. We are trying to tie all of these disparate devices to a PC running multiple instances of OPC servers (one for each network "flavor"). I have gotten the Modbus running, and am close with the BacNet.

    I have not started with the Lonworks yet. I have an Invensys MN800 that speaks Lonworks. This may be our only Lonworks device. Can I tie this device directly to the PC or do I need to establish a Lonworks router for the device?

    If I have to have a router and specific interface card in the PC, what is the cheapest way to go? Do most routers come with an OPC server?

    Thanks for your help.

  2. #2
    Join Date
    Feb 2005
    Posts
    1,218
    Personally don't know of a LON router that has OPC server builtin.

    But if for you the key words are: "the cheapest way to go?" then I suggest you use a gateway device from LON to Modbus and then use your existing modbus interface. This way you eliminate the need for separate network interface and LON OPC sever.
    Something like:
    http://www.intellicom.se/gw_lms.shtml?7&1

    Remember a device like this uses implicit messaging, meaning you will need LON software to bind datapoints from your invensys controller to the gateway device.

    Alternatively, does invensys not offer a LON to BACnet or Modbus gateway, may be even cheaper that way.

    My 2 cents.

  3. #3
    Join Date
    Feb 2007
    Posts
    6
    Thanks Amigo, this helps. I guess what I am struggling with is the different networking topologies. The Modbus RTU uses RS-485 wiring, which is pretty simple and the Master/Slave addressing of the Modbus protocol is pretty simple too (but quite limiting too).

    It seems like Lonworks and Bacnet are a serious step up from Modbus.

    My supervisory software will probably be a custom application written in Labview. Labview can speak to any OPC server, so I was hoping to get all of the devices speaking through OPC so that addressing the devices would be the same no matter what the hardware looks like.

    Since we are a university, we often get a break on software. I am in contact with providers of Bacnet and Lonworks OPC servers and hope to get the software at a reasonable cost. The hardware will be more difficult to come by cheap.

    Thanks again for your help.

  4. #4
    Join Date
    May 2002
    Posts
    9,564
    Call Tridium, maybe they give you a box that can do it all, then you don't need Labview.
    If you have Lonworks software, what are you looking at?
    The reason I ask is that Loytec makes bacnet and Lonworks OPC servers.
    There is also the ilon100 which is a server that handles Modbus and Lonworks.

    Is it part of the excercise to make it exceedingly difficult by utilizing the disparate protocols?

  5. #5
    How did you program the 800? it doesn't have a profile.

  6. #6
    Join Date
    Feb 2007
    Posts
    6
    Thanks sysint. We really need to stick with Labview because we have a background simulation that is forecasting the energy production from the photovoltaic array and looking at the building systems that need to be run to achieve the maxiumum possible points from the DOE Solar Decathlon competition. This simulation will run in Matlab and Labview. At least we have expertise with these two tools.

    At this point I don't have any Lonworks software or hardware. I only have the Invensys MN800 which communicates over Lonworks. What I am trying to do is figure out what I need. I would love to find one vendor who has BacNet and Lonworks OPC servers. If you have a contact there I will give them a call. The ilon100 sounds promising as well.

    I love your question about the disparate protocols. Part of the problem is that we are dealing with donated hardware and software. Another part of the problem is that this is a student-led project and thus our knowledge base is pretty thin. We do have a local MEP/Automation consultant here in Atlanta that have been very generous with their time. A lot of our knowledge is coming from them.

    At this point I have a mishmash of hardware from a few different vendors. Nobody has stepped up to give us the entire building and automation system. We also have a number of PLCs on hand that we may use (for lighting, irrigation, PV position control ...) It really could be a nightmare.

  7. #7
    Join Date
    Feb 2007
    Posts
    6
    We are hoping that our local MEP contractor will program the 800 for us using the WorkPlace Tech tool. Does this sound right? I don't have direct access to this tool and probably not the time to learn it either.

    Quote Originally Posted by PrestonPierce View Post
    How did you program the 800? it doesn't have a profile.

  8. #8
    Join Date
    Mar 2005
    Location
    Pacific Time Zone
    Posts
    4,195
    Gotta ask - have to talked with anyone at Echelon, TAC, or Engenuity to see if they could assist with your project in anyway? I know for our ASHRAE show Engenuity "donated" some parts for use during the show and we just had to return them when we were done.

    http://www.echelon.com/

    http://www.tac.com/us

    http://www.engenuity.com/
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
    http://threedevilskennel.com/ - not my website.
    Versatile Hunting Dog Federation - www.vhdf.org/


  9. #9
    Join Date
    Feb 2007
    Posts
    6
    We are working with TAC through our local mechanical contractor. I may call Echelon directly to see what they can provide. I have spoken to two of the suppliers of OPC servers and they seem willing to provide software for little or nothing. We are hoping that our project provides some good publicity for the folks who help out.

    My thanks to all for their suggestions.

    Quote Originally Posted by crab master View Post
    Gotta ask - have to talked with anyone at Echelon, TAC, or Engenuity to see if they could assist with your project in anyway? I know for our ASHRAE show Engenuity "donated" some parts for use during the show and we just had to return them when we were done.

    http://www.echelon.com/

    http://www.tac.com/us

    http://www.engenuity.com/

  10. #10
    Join Date
    Mar 2005
    Location
    Pacific Time Zone
    Posts
    4,195
    One other thing - if you are looking for sensors, relays, power supplies try Veris. www.veris.com

    Call and talk to Chad Lunak and tell him about your project what you need/want. He's a great guy and tell him the North Idaho/Washington Chukar Hunter sent you.
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
    http://threedevilskennel.com/ - not my website.
    Versatile Hunting Dog Federation - www.vhdf.org/


  11. #11
    Quote Originally Posted by rgentry View Post
    We are hoping that our local MEP contractor will program the 800 for us using the WorkPlace Tech tool. Does this sound right? I don't have direct access to this tool and probably not the time to learn it either.

    Yeah that sounds right, I think I wouldn't be mixing all this stuff in one building thats not really what open protocol is about. Creating a lot of unnecessary headaches, but then again you are looking at it from a different perspective than we are. The TAC guy can get all these done but would have to come up with some expensie hardware to do it, I am pretty sure that both BacNet and LON are licensed in the TACIA UNC, but I don't know if you can actually use both at the same time I have never looked into it or tried( I would guess that you can though).I also don't know where labview fits in, sorry, I don't have much to offer on this.

  12. #12
    Join Date
    Jan 2007
    Posts
    735
    Meshing all of this stuff is real world. It's a good exrcise in what happens out there. See if Tridium will donate something to you. Then at least everything can be integrated and you can get embedded software.

    You may also need to get a Lonworks software tool. Try asking Distech for a copy of Lonwatcher 3. I believe they have a 30 day free tria that you can order.

  13. #13
    Join Date
    Feb 2007
    Posts
    6
    Thanks guys. I have an OPC server for BacNet and Modbus donated now. Working on the hardware stuff.

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