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All,We are using Honeywell Experion C300 controllers to interface with our VSD drives for our expansion project.We would be installing around 200 VSDs all supporting Modbus TCP/IP protocol.Honeywell Experion C300 controller can now talk peer to peer with the Modbus TCP/IP slaves. The only issue is that with current Experion C300, the controller can only have 8 Modbus TCP/IP masters talking to 8 Modbus TCP/IP slaves.We are looking for a device that can sit in the middle acting as a master for mutliple VSDs and slave for experion controller.Can someone please advise if such a device is available preferrably IDA tested?Regards,Syed Hussainsyed. hussain at wapl. com. au

Hello,

While it has never been tested with 200 devices the PeakHMI RLL program has MODBUS TCP master and slave included. It does not have a limit on the number of connections.

And at the moment it is free.

http://www.hmisys.com

Regards,
Mark

I have a Free Software (GPL) project called MBServer which can do this. It is available at: http://sourceforge.net/project/showfiles.php?group_id=228414&packa ge_id=276643

You will also find a link to it from the Modbus.org web site (look on the "technical resources" page).

You would use the mbserver (release 2) package. There is introductory web based documentation at http://mblogic.sourceforge.net/ The package itself has more detailed web based documentation available through a built in web server which is accessable when you install it. I will be adding the content of those additional pages to the Sourceforge web site within the next couple of days, so you will be able to read them without installing MBServer.

The software runs on a PC. There are no limits to the number of client (master) connections, but if you have a lot of connections and are polling at a fast rate you will want a fast PC to handle the communications load. Check the CPU load on your PC as you add connections. If need be, you could split the load between several PCs. The software itself won't cost you anything, so it's just a matter of how many PCs you want to set up.

The size of the messages themselves is relatively unimportant. What matters is how many messages per second are being sent and received. This means the load on the slave (server) portion of the software will be relatively unimportant, as you will be reading and writing fewer larger messages.

If you want to load test the PC, there is another package at the same location called mbasyncserver which can be used to act as just a slave (or you could just set up a second instance of MBServer with no clients active). Set up MBServer on one PC, and mbasyncserver on another. Then set the MBServer configuration to open up 200 connections to mbasyncserver and do the same polling commands you would use for the drives. The reason for using two different PCs is so that the second server isn't adding its processing load to the same PC.

If you are interested and have further questions, let me know and I will be happy to answer them.

Thanks Michael and Mark,

I am more interested in a standalone industrial grade device, preferrably din rail mounted that can act as a server.

We do not want to have all 200 devices on the same server, about 10 ~15 devices would be preffered per server as this will reduce the risk of single point failure.

Can you recommand a device that can serve this purpose.

Regards
Syed Hussain

I think what you mean is you want an "out of the box" solution. You could run MBServer on an industrial PC, and it would be "industrial grade" (including solid state drive, if you want).

As for an out of the box solution, I don't know of a system that is exactly what you want. You may want to consider using some small PLCs as data concentrators. Quite a few support Modbus/TCP with master and slave modules. You would have to program the communications for them however, so it isn't entirely "out of the box" either. Whether you are configuring MBServer or programming a PLC, I don't see how you could avoid telling a system what addresses to read from what drives.

I would be careful about loading any system (including the Honeywell) to its rated limit though. Often, the limit on the number of connections allowed is a crude form of load limiting. The processors in many PLCs (and other proprietary controllers) are relatively slow, and they can get bogged down with communications quite easily. Whether or not this would be a problem for you depends on how fast you are polling.

Typically, it is more efficient to transfer one large message than several small ones. I would suggest trying to group the messages from different drives close together in the memory of each data concentrator so you can read them all with one function call from the Honeywell.

It would be benifical to know the manufacture of the VSD that you are utuilizing. With the Schneider Electric Altivar 61 and 71 drives it is possible to use the I/O Scanner functionality of the various Modicon PLC to acomplish teh task that you are looking to do. The DCS could then communicate to the PLC and control the drives as required.

Thanks Fellows,

We will be interfacing ABB LV and AB MV VSD drives with the Experion C300 controllers.

I have found information on an off the shelf ABB LV VSD module called NETA module that can talk Modbus TCP and can connect up to 9 drive on an ABB proprietary protocol called DDCS. Which is what we are considering. So the DCS would be talking to the NETA card and NETA would be talking to 9 drives using DDCS protocol on a fibre optic ring or star fibre optic topology.

Does anyone have any idea about the DDCS protocol? I could not find any decent documentation on the Net.

We are still looking for a solution for the Allen-Bradley MV VSDs, we are considering an option like Controlnet and then probably a Controlnet to Modbus TCP gateway. Any thoughts on that? Any thoughts on a solution that does not involve a PLC in the middle would be very appreciated.

Regards,

Syed Hussain

Syed Hussain...

I'd have a look at Prosoft Technology's Prolinx line of products.

http://www.prosoft-technology.com

If you don't find what you're looking for, I recommend calling their technical support to point you in the right direction.

Thanks to all the people who provided very valuable information. I have found the device that I was looking for it is Prosoft MNTEC-DNFT module that is an Ethernet/IP to Modbus TCP/IP converter but can be used for my application. It can have 10 Modbus TCP/IP clients and 5 Modbus TCP/IP server connections. 4000 words of memory to store the client data.

If someone needs more details they can contact either myself @ syed. hussain at wapl. com. au or the vendor directly.

Cheers.

Take a look at http://www.sixnetio.com

We have used Sixnet concentrators and RTUs for years with excellent results.

You could use a new Unity hot standby Quantum controller CPU67160. Unity is very easy to program the collection of data from other controllers using the IO scanner cable.