Prosoft MV169-MNET Modbus Ethernet TCP/IP

Guys I have a project where I'll be required to exchange data with an upstream PLC( Schnider) over Modbus/TCP/IP.

On my side I'm using a CompactLogix L32E. I know I have onboard Ethernet available but this unfortunatly is not an option.

I have never used Modbus before and dont know a hell of a lot about the protocol.

Has anyone used this Modbus TCP/IP interface modules before?
Can I set up 2 compactLogix PLCs both with a Modbus TCP/IP interface modules and exchange data for test purposes?

Regards,

Morphuis

Prosoft is your friend!

Weve done tons of Prosoft AB to Modbus conversions and they're pretty straightforward. You can exchange data between the Modicon PLC and the Prosofts or between the two Prosofts as long as they are set up correctly.

http://www.prosoft-technology.com/prosoft/products/for_rockwell_automation/platform/compactlogix__1

Have a look at the bottom of the page on that link - there is a Modbus TCP/IP 'Client Only' card and a regular Modbus card.

Glad tpo hear Prosoft is my friend because I've spent the past 3 days and im not getting anywhere with this!!!!

Admittantly I have no experience with Modbus so that might be a problem. Have you any sample applications where you exchange data between 2 Compactlogix CPUs (L35E) using Modbus TCP/IP with the MVI69-MNET module at each end.

I dont even know for sure if my module configuration on each end is correct? Should it be Client/Server?

I strongly recommend starting with a PC-based utility that performs as a Modbus/TCP Master and let the CompactLogix be the Modbus/TCP slave device.

I've had very good success with WinTech Software's Modscan32.

http://www.win-tech.com/html/modbus1.htm

There is a trial mode, but I bought the license because I use it several times a year for Modbus integration projects.

There are example programs that come with the MVI69-MNET, and in fact they come with RSLogix 5000 too. Start with those.

Also download WireShark, which is an open-source Ethernet protocol analyzer. You'll be able to see the data from the ModSim software and the responses from the MVI69-MNET. Very educational.

I'm assuming your CLX is holding data for the Modicon to read.

If so your Prosoft needs to be a slave.
what part are you stuck on?

Setting up Prosoft cards is pretty much split into 3 chunks:
1) Installing the hardware/hardware confuration
2) Uploading/changing/downloading the .cfg file to tell the Prosoft card what it is
3) Loading ladder logic into the AB cpu to set up the mapping.

Once this is all done and correct youll get the green LED lit on the card. Then you can set up your MSTR blocks in the Modicon and you should be good to go.

I wont pretend its easy ... Prosoft stuff is a little involved but as long as you follow the user manual and take it one step at a time its usually fairly painless.

Ken/SLC

Thanks for your help on this one. SLC is correct, for this project my CLX is required to read/write data from a Modicon. I have never used Modicon PLCs and dont have access to one as its another vendors hardware. However I do have a number of these Modbus TCP/IP modules and was thinking this would be the best way to test data exchange over Modbus TCP/IP learn how this protocol works.

Ken if you recommend a PC based utility I will try the one you have suggested. I am commissioning for the rest of this week so will try it next week.

SLC, I am pretty confident I have the Hardware config correctly. I have downloaded the .cfg file to both Modbus modules, but am unsure if these are correct. Would you mind perhaps taking a quick look at these for me?

Using the sample code that came with the module I am able to write data across the CLX backplane and using the config port/null modem I can see the data is been written to the correct registers. However i am unable to read anything back.

Any help at all on this is greatly appreciated.

Sure send it over.

Once the data moves from the CLX into the Prosoft it sits there waiting for the Modbus Master to poll it (in this case via a MSTR instruction) The ladder will move this data over as fast or as slow as you want, depending how you set up the ladder logic.

One thing to watch is using the terms READ and WRITE in the correct way.

A READ from the CLX side is actually a WRITE from your Modicon as its pushing data into the Prosoft Module that the CLX processor reads in and places into its internal tags.

Going the other way, a WRITE from the CLX side is actually a READ on the Modicon side as the CLX is writing data to the Prosoft in order for the Modicon to be able to read it.

You should be able to set up the two Prosofts, one as a master, one as a slave and make sure a value you change in the slave is correctly transferred into the Slave Prosoft, polled by the Master Prosoft then read in by the Master CLX. Its a bit of a convoluted path but if you want AB to ever talk Modbus, Prosoft is your friend!

MorphuisOGrady said:

Guys I have a project where I'll be required to exchange data with an upstream PLC( Schnider) over Modbus/TCP/IP.

On my side I'm using a CompactLogix L32E. I know I have onboard Ethernet available but this unfortunatly is not an option.

I have never used Modbus before and dont know a hell of a lot about the protocol.

Morphuis

Click to expand...

In april I read that Schnider had become a foundation member of OVDA, Read link below .
Would this not mean it is, or will be possible that they could communicate directly with each other.
http://www.odva.org/Home/tabid/53/ctl/Details/mid/372/ItemID/21/Default.aspx

Not yet. Schneider developers are working on implementing EtherNet/IP but it's still very much in the development stage.

SLC,

I am back in office this morning so i will attempt using Modscan as Modbus Master. I have attached the two configuration files ( as text files) for both Modbus Master and Slave TCP/IP modules.

Thanks for your help

Modbus.org

Try and have a look at the Modbus.org site. They are an ambitious group who are trying to maintain a global convention in the use of the protocol. They have a number of informative guides--a breakdown of the protocol, wiring techniques, and links to Modbus equipment sites all for free download.

We primarily use Prosoft's serial cards for the SLC-500 (5/03 and 5/04 processors) to poll some KEP and Red Lion gear for data, but also have some of their PLC5 serial cards to operate a hand station for some AB drives.

They make a highly reliable product although I've found the documentation and example ladder to be lacking in some areas. One item of note is that the cards are capable of providing diagnostic data. I needed an indication when a field device dropped comms so I could both be alerted to the dropout and had the option of moving zeroes into the registers. The default is to retain the last good numbers. I had to call them to get this info from one of their engineers. Very good staff there though--

The Modscan32 software is a must--we bought our copy about 5 years ago and I use it often.

Anyway, good luck with your project.

Guys,

Thanks for your help, got it sorted. Have 2 compactLogix PLCs now reading/writing over Modbus/TCP/IP. That Modscan32 proved to be an invaluable little tool. Once I got the correct modbus functions to do as required the rest was simple.

The .cfg file required a little altering too.

Morphuis,

For your application, are the Modbus modules configured as Master or Slave?

I have a project that requires three-way PLC communication, as well as Modbus link to DCS. For the former, I have the option of either hardwiring or Ethernet via Modbus module. Any suggestions?