Controls In General
I have an ever increasing experience and background doing general conrol systems for refrigeraton and light commercial HVAC systems. I am versed in Danfoss AK55 Ak255, CPC from Reflecs to Now the E2.
I just returned from a CPC class. I have installed alot of the CPC stuff.
Okay most of what I have currently known as "controls" have surrounded the concept of rs485, rs232, and some lon. In the world I have been living in, it is really not required to breakdown the issue to slicing atoms, rather, they show you how they want the network wire ran, on what ect. Then the programming is generally answering questions in a predefined format. Nothing like Boolean logic equations which I am starting to understand.
Now. I guess I am having trouble with the understanding of some things.
I was on a project that said the controller that was to be my HVAC controller was compatible for lon. I was doing their oem RTU boards, but I had a carell controller for a munters Dehumidifacation unit. It was a carell controller with a lon card. It did not exactly work by hooking it up and away you go. There was something in my building controller that was not properly able to interface. They said it was lon, but it wasn't. The carell was a true lon device with the lon card.
Now. Don't get too in depth about that. Let me ask though. If it's lon, thats the language it speaks over the wired architecture? Is that a correct way to think? SO here is my questions. Whether we are talking lon, bacnet, modbus. The language is the protocol. And in that protocol, a command to close a digital output, a receive a signal via a analog input, if the device is the same lanugage as the main controller, am I to assume it's gonna work with out issues. How does it get mapped out? What states, on this device, this command is this action, at this point?
First the Lon card has to be commissioned for it to work on the network.
I realize that. I may not have been clear in my question. I was using that carell and building controller as an example of things I run into.
I am just saying. The controller, the main conroller has to be able to read lon, and the end device has to be able to read lon. But. In lon or bacnet or whatever protocol, how does the overall communication act. If for instance, I am a BACnet controller. I speak english and I speak it at this speed. I have a southern dialect. But I am talking to a spanish (lon) device. This would require a translator. A Gateway. What I want to know is. The BACnet says, close digital output point x, and sends the command out, to the gateway, then the gateway translates to spanish (lon) and sends the command to close digital output X. When I am working with different manufacturers, and and different communication protocols and different wired architectures (media), I want to know how does it know what digital output point x is.
Is there a legend, that says in Bacnet, this is address,device, command ect and so forth.
Slice me up an atom. I am unable to bridge the concept in my head at the moment.
I hear you guys talk on here about mapping points with a gateway. Well how do you know how to map a point unless you have a baseline to start.
Ok I get it, lets take a Boiler on Lon and OSA Temp on BACnet. We want the to only come on if the OSA Temp is less than say 68 DegF. We need the two systems to talk to each other, how do we do this. There are gates that can do this but most often you can't use them, so now what. Well there is a few options that will get it done, INet, Tridium, Field Server, I believe Smart Server can also, to name a few and there are a lot more. Now we bring the BACnet point OSA Temp in to what ever and we bring the Boiler point into what ever and we add a compare, then link it all and presto it will work.
All those D's, I havent done any Bacnet or Lon but I have done some Modbus stuff. This is what happens I have my controller and say a Carrier RTU with the Modbus Translator card. I can put the card in the unit and let it discover the first points on the point list or I can use Carrier's software to program the card using the RTU manual point list. Once I have my Carrier translator card reading the points I want to the RTU I look at the manual for the card and see where I mapped the points too. I then go to my controller and program my controller to look at the Modbus card(address, baud, etc.) and map the points to the controller based on where I placed them on the card. I hope this is what you were looking for.
Last edited by joey791; 10-26-2008 at 03:16 PM.
Originally Posted by MatrixTransform
okay. I am gonna talk out loud here to see if I can get this.
Using the problem I had with a carell controller. Now. Remember before I talk about this. The problem got handled. This is just for practice example. This carel was on a Munters Unit. The munters guy had emailed me the carels points map for his application. I was easily able to understand this. IO basically. The carel had digital outs 1 through 8 lets say. And those outs were defined by them. Lets say out 3 was Stage 1 heat. And with using the LCD of the carell conroller I was also able to see that indeed point 3 was stage 1 heat. I can understand that. Device address, what ever, then the point. And what kind of a point. It was on device 1, it was a digital output and it's output was on output point 3. Digital. No problem. Am I right. Cause then if I am, this stuff is no different than I already know I understand and it shows I can expand on what I already know.
I assume they took a carell controller that had x amount of inputs and outputs analog or digital. and they just assigned those points for however they wanted. Say the point three on digital outs, were gonna call that stage 1 heat.
Now. Say the carell communicated all this crap out of the controller via Modbus (which is a communication protocol)
It was manufactured to be Modbus communication. So. If I had a Modbus main controller, the main controller would easily be able to interpret the signals on the wire (media) from this carel controller with out any real integration. Due to the fact that these two devices were manufactured to talk over the media (the wire) via this protocol (modbus).
They both know that we have predesignated digital out 3 as stage 1 heat, On carell controller device address whatever. The main controller, manufactured to read modbus, it's now gonna show me, hey dude device 1 on output 3 is stage 1 heat.
My main controller might then be the guy which determines occupancy and scheduling and whatever, maybe even setpoints. So when the main controller wants this address 1 carell controller to put out some heat based on a setpoint and an input from zone, it commands the controller to close digital out 3. Stage 1 heat. And because they are both MODBUS, this aint no problem. Both main and device know that stage 1 heat is output point 3.
Okay. If you guys are with me and I am talking correctly, than we'll get to the next 11 questions I have.
No, it wasn't a "true LON device". It is some controller with a LON interface. There is a difference. Usually you have data and timing issues since your controller speaks "A" to the Lonworks interface which then makes data available on the LON network. Nearly 100% of the time the issue is with the controller and the interface and not the LON network. I have yet to see a manufacturer get this right. If they would simply make a LON device, problem solved. Of course these OEM's and small controller manufacturers that work in OEM don't want that... I guess too much work to follow a standard. Although, you will hear every sort of excuse such as I can't get enough variables if I use LON, etc... the reality is they are not technically competent enough. Not saying this is easy, just saying they can't get it done.
Originally Posted by Dowadudda
The controller would only know once you tell it to look where for what information but you have the jest of it. The Lon stuff will have to be handled by the other guys here because I cant really give any input(no experience)
Originally Posted by MatrixTransform
Well I am mixing myself up trying to achieve a higher level of understanding here. I understand it had the lon card and it was not a lon compatible out of the box to begin with.
Originally Posted by sysint
Originally Posted by joey791
Okay, the jest of it. Here is my question. I don't care if it's lon, or friggen anything. I could really care less. I just want to know. It all boils down to device adress, board and point right?
If thats the case. I have realized I know more than I thought I did.
I do alot of supermarket controls. Danfoss, CPC, Novar. Which is bascially all things refrigeration and most HVAC under 30 tons. Lighting by controlling different switch gears ect. And I just basically wanted to know how much different or how much the same it is from most of the things you guys talk about on here.
I'm getting the impression you think this may be plug and play after tinkering a little bit. Unfortunately it's not. Ask anyone here and they'll tell you "LON is not easy" when you are first learning.
Before we go any further, was there a neuron ID on the Carel? It would look ole a bar code - this becomes your unique address for you controller. There are no two neuron ID's that are the same.
Was there a service pin (usually a black button push button on the LON card)?
You may have already said it before, but what is your network (main controller)? Tridium JACE? Something else?
Your hardware i/o has software i/o that commands or interprets them. This is what creates the points lon, modbus, what ever. An interface card interprets the information to/from the unit and converts them to the software points. In order to make other controllers see them you need to connect them to each other with some type of master controller. That master controller has to be told what to do with the software points in order for it to work. All 3 of the controllers may require different software to program them and mapping the points to one another can be an intense process. It is not recommended to try to integrate without training there are way to many steps to try to get right by just clicking away.
"It's always controls"
Originally Posted by simsd
Like I said 4D's, I dont know the Lon stuff so these guys will be able to help the rest of the way
Originally Posted by MatrixTransform