View Full Version : Need an explaination
01-12-2005, 11:58 AM
Can someone explain to me what LonWorks and BACnet are to the controls field…. Are they the equivalent of open source to computer programming… it seems as though they can be made to work with many EM systems…
01-12-2005, 12:09 PM
Lonworks and BacNet are the type of communication language that controls talk with. I would compare it to either cell phone technology such as CDMA, GSM or PCS. They all will get the same job done but they all do it a little different. Lonworks is the newest of the communications protocol and there are + and - to each. Lonworks is open to many types of equipment other than HVAC and has standardised profiles for what the equpment does.
Lonworks code is written onto the Neuron chip, this chip carries the communications protocol and the address. If one was to write a blank program from scratch using a non programable controler. (Creating a prototype) He would use Neuron C. If you are writting a custom program for a controller that is set up with the ability to custom program (TAC 401's or Trane MP's) you would use that manufactures software that was developed strictley for that controller.
To make Lonmark equipment communicate with each other you use software such as lonmaker, Rover..... This creates communication bindings between the controllers you wish to share information with. You have to create bindings for each point that you wish to share with others...
There are many other factors that come into play but this is some of the basics...
01-12-2005, 12:27 PM
There would be exceptions -
Circon and Distech programmables do not need a 'custom program' to set up the devices. It can be done.
You also don't need a Neuron chip anymore.
I should also point out you don't always need a "bind" for controllers to share information.
A real basic difference is that with Lonworks you may use a common toolset to setup controllers from multiple vendors, whereas with BACnet you need each vendor's toolset. Subsequent vendors can come in and utilze this toolset to add devices and change the network without becoming (completely) dependant on the previous contractor.
I would say Lonworks is more like Microsoft(regulated/open) and BACnet is more like Linux. (unregulated/open)
I would also say there are companies out there on both sides trying to screw up the open. (harder to do with LON)
[Edited by sysint on 01-12-2005 at 12:29 PM]
d big 1
01-12-2005, 01:34 PM
I like where this is going. I have a question. We have both LON and BACnet and are understanding to some small (very small)degree the advantages of each. Which way does it look like the industry is heading? Maybe this should be another thread?
01-12-2005, 02:04 PM
"A real basic difference is that with Lonworks you may use a common toolset to setup controllers from multiple vendors, whereas with BACnet you need each vendor's toolset. Subsequent vendors can come in and utilze this toolset to add devices and change the network without becoming (completely) dependant on the previous contractor."
When you say toolset, is that the address points? The only thing I've seen is, Lonworks requires a Loncard to communicate to the equipment controllers. With Bacnet you can communicate directly to the individual points, provided you have the addresses. Right now going through a horror show trying to get Carrier Loncards to communicate to EMS.
01-12-2005, 02:05 PM
I would say that the Lonworks side is definitley growing. But there is still alot of equipment manuf. that do not offer Lon cards for the equipment. I would guess it will be going to LOn in years to come, my reason for saying is the multiple choices in the comunication form, FT-10, TP-78, TP-1250, Fiber just to name some. They all offer different speeds and capacitys.
This could turn out to be an endless topic.
01-12-2005, 04:37 PM
Rowe- LNS Lonworks generates a database. Once a device is identified and commissioned, you have access to all the points . (nvoSpaceTemp, nvoUnitStatus, etc.) There is no need to map any points, even through mulitple mediums.
Additionally, if you examine the link I provided just recently on Lonworks you will find many controllers functions have to be identical for minimum standards of operation via Lonmark. That means that every Lonmark rooftop controller has common points such as nvoSpaceTemp, etc.... for better interoperability.
I can use the specific vendors plugins in the LNS database to configure/test/setup/monitor their devices.
Your "Loncard" makes your computer, server, (whatever) a device on the network. You could also have a RNI with is a connection more along the lines of what you are talking about.
With Lonworks you communciate with the device or the points. Also, you don't need to talk through a mapped location to other vendors devices. (as seen in BACnet) Communication is direct device to device.
I beta-tested the Carrier LON cards. The problem in the Beta was more the interface between the CCN and the LON card. You have to power the CCN first. Carrier likes to be difficult. They want you to use CCN. What's your network tool (EMS)? I'll bet that's more your problem than the Carrier LONcard.
As I've said before Lonworks is a very good communication structure. 45+ million devices out there. But, the ASHRAE crowd isn't about to fold tent and the manufacturers realize they can keep separation hiding behind BACnet.
01-13-2005, 07:31 AM
This may have already been said and obvious to some, but in an answer to the original question, LonWorks and BACnet go further than the communications protocol - they provide data definitions as well. It is really the data definitions that provide the useful description of the equipment / controller to be interfaced. LonWorks provides network variables and configuration properties of basic types (SCPT and SNVT list that at one time were avaiable from lonmark.org)) that are understood by most, and BACnet uses objects (binary input, analog output, all defined in the BACnet standards published by ASHRAE) and services to access those objects. Sometimes, you might even hear LonTalk thrown into these discussions - that is actually the communications protocol upon which the LonWorks (communications protocol and data defs) system is based.
Open source basically means that source code is available to those who use open source software. Then if you want, you can modify it to your likes. But that is not really what LonWorks and BACnet are about.
01-13-2005, 08:06 AM
thank you all for the great responses, there is a wealth of information on this board...
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