MODBUS protocol

Is there any C-Bus interface to get a two way communication through MODBUS protocol?
I am interested to integrate C-Bus with large BMS installations like Honeywell or Johnson Controls.

 

Relevant application note?

Copy from Building IQ issue four winter 2003:
CIS Hong Kong?s success is largely due to our expertise in systems integration with other Building Management System suppliers such as Siemens, Honeywell and Johnson Controls. They have successfully demonstrated the capability of C-Bus to integrate with different standard protocols including, Modbus, OPC and BACnet. More recently, CIS Hong Kong has issued an application note to share this valuable knowledge to other CIS offices worldwide.


I tried to find the application note but I can't find anything before 2006. Where can I search for older application notes?

A device-translator to modbus will really help us to participate to large commercial projects. EIB has a module and it costs about 180?. Metasys (to talk to Johnson Controls) cost 20 times more....

 

2SC, I dont have any experience in what you are trying to do, but maybe these threads will point you in the right direction, and help you focus your search a little more specifically:

http://www.cbusforums.com/forums/showthread.php?t=96&highlight=ModBus
http://www.cbusforums.com/forums/showthread.php?t=2875&highlight=ModBus
http://www.cbus-shop.com/product_info.php?products_id=159
http://www.wmitechnologies.com/pdfs/Niagara_Connectivity_10-2005.pdf

Hope this helps

Darpa

 

I read all the relevant previous posts but I decided to start a new one since a lot of time has past.

As I wrote before, I am interested to find a cheap - reliable - easy way to communicate with large BMS installations like Honeywell or Johnson Controls. In commercial projects where a BMS is installed, most of the times a secondary bus system has the control of the lighting system. If there is a need for full integration, EIB has a cheap device to communicate with BMS and gets the whole pie.

As Richo said 2 1/2 years before

And PSC added:

I hope to made myself clear now....

 

ModBus Gateway

Clipsal Asia have a hardware gateway that supports ModBus over TCP/IP and RS485 part number 5913M23000. Try the team in Hong Kong for more details...

 

Dear Stace,
You may not remember but you replied in a previous post of mine on the 2nd of February about EZinstall and Premise Gateway. Following your suggestion I emailed twice to both [email protected] and [email protected] but I never got a reply.
Then I tried the hard way, through the local Schneider people but I never got an answer too.

Although I am not 100% sure that PG is what I am looking for you are giving me the courage to try another time. After all Premise gateway seems too interesting...

Anyway, if you could pass my e-mail address ([email protected]) to anyone that could help me, I would be grateful.

Thanks,
Antonis

 

In theory all protocols are interchangeable through an object library and a processor.

 

Tobex,
Wheels are already invented and I need them to make a car.
I mean that Clipsal should offer us all the necessary utilities and equipments to make our life easy and the product more flexible and competitive.

 

Perhaps. The thing about Clipsal technology is that it is intuitive and friendly thus giving the impression that all problems are solved so easily. The bottom line is that true integration is a minefield of industrial code and obscure syntax. I prefer to use dry contacts for that reason. It means that you can reduce any function into an operational logic condition. At least then you are not limited to any specific certification.

You can be certain that one week after a bridge is developed that Seimens will invent a function which C-Bus can not control. Generally what I find is that most (domestic) systems are so badly designed that controlling other systems is quite difficult. For example, installing an operational detector for the climate control meant installing an air vane inside the main duct. Apparently that was the first time the AC installer did such a thing for a house and he couldnt understand why it was needed. The owner wanted to know if the AC was running and no person could tell me another way of doing it simply. The air vane made a dry contact.

From my personal experience, I would also check the design of the BMS to see if it actually performs the functions it claims to perform. At least then you can break it down to logic states, which C-Bus and any other system can interface easily.

Sometimes people confuse integration to mean "reads other code" and not actually to mean "performs seamless logic". In other words, when I press a button or trigger a sensor the function is completely predictable.

 

Tobex,
I don?t want to argue with you. In fact, I prefer myself dry contacts for small or domestic installations.

However in a large commercial project, where I try hard to get a contract as subcontractor of Honeywell or Johnson controls, I have to follow their rules. So if they want a modbus translator I must give them a modbus translator or else adios contract.

One more thing. I want to see C-Bus leading the market not following others. That?s why I am often complaining in several posts about thermostats, weather stations, shutter relays etc.

 

It is a bit like saying that you lost the International Space Station contract because you didnt have a C-Bus Zero-Gravity Retro-Rocket module.

If C-Bus does not perform to your specification and you have limited control over the site then it is already doomed from the start. The only thing I can think of is a custom PC project with both interfaces running at the same time with PC related translation.

I didnt see in any comment as how large the translator must be and a developer kit is already available as are restricted protocol documents.

The entire PC could be about the size of a small stack of DVD covers and have no moving parts (not even a fan). Once you look at software tools there is no effective restriction.

 

2SC, I just subscribed to this thread as I also need some MODBUS integration. I did a quick google and found something that might be of interest in the C-Lution package. They say it can integrate with 3rd party devices. Maybe someone can shed some more light on this.

 

C-Bus ---- Input logic ----- output logic ---- MODBUS interface ---- MODBUS

Perhaps I am too simplistic but dont understand the problem. If you want to report back to the MODBUS as to the status of each C-Bus module then I suggest you also wire back the STATUS pin in the modules or at least the remote operation pins.

Unless someone can describe the scope of the problem and whether it is unidirectional or bidirectional data transfer then I would say that unidirectional data transfer is done with hard logic or software bridges.

Bidirectional data transfer would need a PC based solution to output the functions and status of data on the C-Bus network.

Is there some example of the logic being controlled ?

 

I don't want to hijack this thread but all I need is to monitor several MODBUS registers and display their values on either a touch screen or on Homegate. My plan was to use a seperate package to manage MODBUS but that wouldn't be ideal.

Maybe something running on my Homegate PC that can translate between MODBUS/TCP and CBUS?? Hmm... Something like.. Place Monitor -> Type Third Party -> Network MODBUS Translator -> Unit Address/Register Value.

 

Thanks Ingo for the idea. A device like this may help to get easily information from many devices like VRV units, electric meters, etc that they use MODBUS protocol.

As Stace posted, Clipsal Asia has the answer...

 

i want to connect c-bus istallation with bms system running on modbus

 

Ok this is an honest question. What is the connection supposed to do ?

 

Hi,

Im probably one of the few people that have had a play with the Modbus Gateway that Stace mentioned in an earlier post. It is quite easy to use once you have a little experience with Modbus.

Just to give you a brief overview of what we have at the moment, the Modbus Gateway can:
- Communicate via Ethernet, RS-232 & RS-485
- Map 512 group addresses (2 Applications) to Modbus Coils & Registers

The Modbus Gateway does not support C-Bus network routing, but if your installation is using Network Bridges, the bridges can do the routing for you. Ideally if you a using CNI?s you will need a Modbus Gateway per C-Bus network (as it does not support tunnelling).

I use Modscan32 software to test it?s functionality and that works quite well (if the gateway has been set up to correctly).

As Ashleigh mentioned earlier it has not been released yet, but I?m sure that once development and testing is completed, it will be a very handy solution to a lot of BMS integration problems.

Ingo mentioned C-Lution. This is basically Citect SCADA with the Clipsal branding. Think of C-Lution as if it were Schedule Plus. It allows monitoring and control, scenes, schedules, logic etc. Where C-Lution stands out, is that it allows integration to other protocols such as:
- Modbus
- BACnet
- Lon
- OPC
- DDE
- 1000?s of PLC divers.

So C-Lution has all these drivers, but it also has a C-Gate Driver that allows the software to connect to the 127.0.0.1 20023 TCP/IP socket. So that?s how you can get C-Bus to communicate with Modbus (via C-Lution).

Although C-Lution does solve a lot of integration problems, it does come at a cost. You may find that the development of a front end is a lot more difficult than Schedule Plus, and the licensing costs of the software are much higher than a Unlimited C-Gate Network License.

I hope this helps.

Age

 

does anyone know at the moment where to get this ModBus gateway?

my client wants c-bus - ventilation integration and ModBus seems to be the best solution for this