Logix on modbus

I just started working on a project that will put a compact logix controller on modbus scada server. The server is running fix32 with MBR driver. This is a new remote site. The existing sites are modicon plcs. What I need ideas on are how to get the compact logix communicating over the modbus. We will be talking serially through RS-232. Here are my two ideas

1. Connect the RS-232 cable to the compact logix directly and use code to traslate the Compact logix to the mbr format. I talked to AB and they sent me a manual and sample code, but it looks pretty intense. If I go this route will it be worth it?

2. Connect serially to a pro-soft card. This seems like the easiest way but more money.

I would like to use option 1, but I dont want to spend a lot of time on it then switch to the pro-soft card. There is not a lot of time and I am still new to all this. Also we will be using DF1 radio to get this to the fix32.

Any suggestions would be greatly appreciated
Thanks
Tim

Unless you have a terminology error, this will not work at all. You state ifix32 is using a modbus driver, but then you also say you are using a df1 radio to get this to ifix. Which one is it?

If it is modbus, I would use the prosoft card. Leaves the DF1 port open for programming, panels, etc. I have never had an issue with a prosoft card, and their modbus is super easy in CLX

My fault, I got confused. It is modbus Here is what I got to go from

(1) Existing site has Intellution Fix32 using ethernet to communicate with local modicon PLCs. The Intellution SCADA server is also using an Intellution serial driver (a MBR) to communicate through a radio to remote sites. These remote sites are also modicon PLCs.


(2) A new remote site is being added to the system…4 VFDs and a couple metering pumps for chemicals

(3) Our best option would be using the existing Intellution MBR driver to communicate to the compact logix. If not we may have to look into using some sort of hardware solution such as a prosoft card
Sorry again for my mistake. Have you ever not used a prosoft card?

I don't know much about modbus but there is some example programs that came with RS-Logix that you may find helpful.
Steve.

I have those. I am hoping that that is just a can program I can throw in my project. Has anybody ever used these? I am going to try these programs first.

timmyh said:

I have those. I am hoping that that is just a can program I can throw in my project. Has anybody ever used these? I am going to try these programs first.

Click to expand...

Depends how critical is. Personally, I would never use the modbus program.
A) How long will it take to implement.
B) How easy is it to maintain
C) How is the performance

I know prosoft works, and for the cost, its a relatively cheap solid solution

Sm2

I suggest that you use the 1769-sm2 module from RA, as it's relatively easy to set up.

I just finished a project using one with 4 Altivar 71 drives, and I'm about to start a new project where I'm going to use one as well.

I made some UDT's that might be helpfull. I can post them on monday along with a sample program if you want.

Another good thing about the sm2 module is that you can get support directly from Rockwell

If you want to post them or send them to me that would be great.


Tim

ghettofreeryder said:

Depends how critical is. Personally, I would never use the modbus program.
A) How long will it take to implement.
B) How easy is it to maintain
C) How is the performance

I know prosoft works, and for the cost, its a relatively cheap solid solution

Click to expand...

I second this approach.

Not the cheapest but its easy to set up, works and does exactly what its meant to. You could scratch around for days trying to get the Logix approach to work and end up spending more.

Sorry for the late reply.

Here's the sample program.
This is only the communication to the 4 drives, I havn't started programming this yet.

By the way, in my applications the controller is the master, I'm not sure what you want as the master/slave on your project.

Take a look, and ask if it doesn't make sense.

This is the manual for the sm2 module:

http://www.theautomationbookstore.com/idc/groups/literature/documents/um/1769-um013_-en-p.pdf

Tim,
We have an EtherNet/IP - Modbus RTU gateway that may interest you.
Part number is 451EM. Here is a link.

http://www.rtaautomation.com/ethernetip/mbm2eip/

Rick DeMorrow

I've used the RSLogix5000 sample code for Modbus RTU slave over the Channel 0 port. Its easily dropped into a periodic task and runs rather well. I haven't been able to trip it up yet. The best part is that its free. It is intimidating, but the documentation shows you what to modify to customize it. Its really pretty easy without having a total understanding of how all the sample ladder works.
LINK

I've also used the Modbus Master RTU sample code for RSLogix5000. Its almost as easy to use.

Otherwise, a RedLion Data Station Plus is another easy way to get Modbus RTU. Its a personal preference on how to get there... but the Prosoft card will just cost more and be more difficult to configure.

I am looking into that modbus rtu gateway now. I ended up using the logix code to get the modbus. I only had a couple problems. When ever power was lost you would have to clear the buffers, but that was an easy fix. I also had a couple other problems that I cant remember off hand. Other than that it has been working great. I am on another project right now that I am going to implement that program (if we do not go down the modbus gateway route). Thanks for all your input.

Timmy H

ML1100 or 1400

You can also use the ML1400 or the ML1100 as the modbus interface. The ML1400 has two serial ports where one can be the slave and the other the master. The ML1100 has only one serial port so you can only select Master or slave. The cost is about 550 list for the ML110 and the list for the ML1400 is about 850 which is much less than the Prosoft Module. Although it is easier in 5000 software there is still a learning curve for Prosoft. One problem with this solution is that the MicroLogix cant handle Floating Points yet so that would be the only issue if it is one.

I have used a prosoft card for Modbus over ethernet on a a Conttrol Logix system. It wasnt that bad to get going. Use a software program like Modpoll to verify that you have the card configured correctly. Have had the card installed for about 3 months now with no problems.