Modbus TCP And ControlLogix

AzCtrlEng

Member
Join Date
Aug 2011
Location
Phoenix
Posts
20
I have a ControlLogix system that has been running for awhile now. I need to read data from this controllogix via Modbus TCP. I can change the controllogix code as needed but cannot add any new modules. How can I read tag data via modbus tcp? From the modbus side of things I need to enter an address i.e. 40012 and have that correspond to a tag in the controllogix i.e. DataTag. I have been told this is possible but cannot find any examples and the person who told me about a system like that can't remember how it was done but states it was all through programming in the controllogix and no extra modules or converters etc were needed. So does anyone have any ideas? Thanks!
 
I have a ControlLogix system that has been running for awhile now. I need to read data from this controllogix via Modbus TCP. I can change the controllogix code as needed but cannot add any new modules. How can I read tag data via modbus tcp? From the modbus side of things I need to enter an address i.e. 40012 and have that correspond to a tag in the controllogix i.e. DataTag. I have been told this is possible but cannot find any examples and the person who told me about a system like that can't remember how it was done but states it was all through programming in the controllogix and no extra modules or converters etc were needed. So does anyone have any ideas? Thanks!


I would (and have) used a Redlion DSPLE as a gateway between ControlLogix and ModbusTCP.

http://www.redlion.net/Products/HumanMachineInterface/DataStationPlus.html
 
None of the A-B Ethernet modules for ControlLogix support Modbus/TCP.

The Prosoft MVI56-MNET module is the most popular chassis-mounted module for this, but since you ruled out adding modules to the controller, that's out.

You need an external device of some type, but the sophistication of that device versus the cost of that device is the equation you have to solve.

The least-risk option is a Prosoft stand-alone Modbus/TCP to EtherNet/IP gateway, the 5201-MNET-DFNT.

Another platform for EtherNet/IP to Modbus/TCP connectivity is the HMS Fieldbus Anybus-X.

Rounding out the possibilities, in the lowest-cost, lowest-performance, and highest effort would be the implementation of Modbus RTU protocol on the ControlLogix serial port (Search "Modbus" in the Sample Code Library), and the use of an inexpensive Modbus TCP to Modbus RTU converter.
 
Since Decembre 2012 there is a sample code for Modbus TCP in ControLogix. using the stanrdard Ethernet modules. (Search "Modbus TCP" in the Sample Code Library). It is not very compact and seems to be very limited (only one connection, 100 registers, etc) but is open source. Did some of you already use it?
 
Hi

I downloaded the code that is been spoken about to connect to a vision sensor and I did not get it to work. Now that's not saying it will not work but it's not simple and you would really need a very good handle on modbus which I don't.
I could follow the code and even got a connection opened but failed the get the modbus address from the vision sensor to the plc. I changed the sensor to a Ethernet ip module and had it working in no time.
I have also used the Anybus modules from modbus to device net and I have to say it was also very good. Can not comment on the stand alone module Ken spoke about but I have used the chassis based one and it also was very good.

Donnchadh
 
I have a digi one iap does anyone have any experience with it. I need to go from a control logix plc thru it to a modbus rtu device. I've had zero luck
 
You will have better luck starting your own thread, explaining your issues, goals, and hardware.

This is from 2013 and the title doesn’t match your problem.
 

Similar Topics

Hello all, I was wondering if you clever people could help me, please. In the past I have used a standalone L33ER CompactLogix PLC with the...
Replies
5
Views
1,464
I am working on a project, inside an AB CLX, I implemented the Modbus TCP Client AOI published on AB website, to interreact with a Modbus ASCII...
Replies
7
Views
3,459
I am not very experienced in Rockwell PLCs and have run into a small problem, so I could do with a little bit of help. We have a redundant...
Replies
3
Views
2,470
Hello All, I'm looking for the Coles notes on how to inferface a Modbus TCP device (compressor controller) with a Logix 1756 L72 running V24...
Replies
14
Views
5,783
Hi all, I'm working on a wastewater plant where I have a ControlLogix PLC as the master PLC, alongside three packaged systems that are being...
Replies
10
Views
3,756
Back
Top Bottom