Modbus Protocal for SLC 5/04

Hello all, I am currently attending Oklahoma State University Institute of Technology and I am in my finial semester. I am working on a capstone project that includes a flow loop which has flow meters and pressure transmitters and level sensors and much more really fun stuff. I will be using an Allen Bradly 5/04 processor to program my flow loop. However I want to also incorporate a DCS program (we are using Delta V) which will have a diagram of our flow loop and the user will be able to see live data (ex. flow rate, tank level etc.). We are trying to make a trainer for future students to train on and make it look like a real world scenario. I was wanting to use a wireless gateway to communicate to the delta V, my SLC 5/04 would be wired into the wireless gateway. I was wanting to use a modbus protocol so my DCS system can see live information from my flow loop trainer. My question is does Allen Bradly have modbus communication I have a series C FRN 8 processor. I might have to buy an Upgrade kit but I also have a budget to work with and I already have a list of things that are adding up, so if I buy this I want to make sure it works. Thanks

The hardware you have won't run the protocols you probably need.

The SLC-5/04 operating system did add Modbus on the serial port in FRN10 (which can be upgraded using a re-usable EEPROM chip) but it's Modbus RTU Master only.

In general, DCS and SCADA systems function as the Modbus Master and remote devices function as Modbus Slaves. You can't run Modbus Master-to-Master communications on a serial link.

Does your installation of DeltaV include Modbus/TCP (the Ethernet-based version of Modbus protocol) as well ?

If this were my system and I could only buy one piece of hardware to make it work, I would get a Digi One IAP or a HMS Communicator, which can talk to the SLC-5/04 over DF1 serial protocol (native to Allen-Bradley serial ports) and to third party devices like the DeltaV over Modbus/TCP.

Ken, Doesn't Prosoft's backplane card run as a Modbus Slave?

danw said:

Ken, Doesn't Prosoft's backplane card run as a Modbus Slave?

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Master or slave, or both.

http://www.prosoft-technology.com/content/view/full/135

http://www.prosoft-technology.com/content/view/full/5757

The Prosoft MVI46 would be a very straightfoward way to connect these systems, too.

It's flexible, fast, and relatively straightforward, with the added benefit that the configuration is all done in PLC logic and data tables, so there's no added software package and configuration to back up and document.

The downside for a university lab project is that it's relatively expensive and can be a challenge for novice programmers.

Ken Roach said:

The downside for a university lab project is that it's relatively expensive and can be a challenge for novice programmers.

Click to expand...

Worked with the ProSoft team a lot and they may be kind enough to sell you one at a greatly reduced price or let you have one. You might ask... (I know Rexel in Tulsa handles them)

A DCS system should be able to talk DF1 which is the protocol that SLC500's use. DF1 is better than Modbus because the address space is bigger and isn't as timing dependent which is critical if the packets must go through buffers, isolators, converters or what ever might mess with the timing.

I can't imagine a DCS system that doesn't support DF1 and it is a lot cheaper than buying a card.

As I understand, DeltaV sells separate licenses for the serial protocols on their serial module. Modbus is the standard part number, and DF1 is another.

I've actually seen a lot of trouble with DeltaV's Allen-Bradley related protocol interfaces. In the real world outside a classroom or lab, I would use Modbus just because they can't blame problems on the protocol.

I think Peter is right about DF1 being faster, even though we used to call it the "Allen Bradley Data Sidewalk". However, I second the use of the ProSoft cards because of expandability. They are easy to set up, and have multiple ports, including Ethernet. I would expect that at some point someone will want to add a smart transmitter or PC or something to the network.

First off, I want to thank everyone for there replies I love this forum it has helped me in the past with my college career, and I always try and look up what has already been posted before I need to post something myself. I will continue to use this forum in the future for my work career.

With that being said I did some searching through the schools inventory of Allen Bradly modules, I found a 3150-MCM its from Pro Soft its a 1747-KE Ser C FRN 4 I hope this one will work. Our capstone group is going to do a test next week to make sure this will work. Also I found out the module on the Delta V that I will be communicating with is a Mynah VIM-4210.

http://www.mynah.com/pdf/VIM_Network_Gateway_Product_Bulletin.pdf

It looks like we will be able to save money, if so we have other things we need to buy to make this project come together. The fun part is figuring out how to program the module and establish communication (trial and error)

The 3150-MCM is the first generation Prosoft module for the SLC-500 family controllers. The "1747-KE" is the A-B hardware on which it is based (it's an old 8051 system-on-chip !) but it's running Prosoft's hardware.

Prosoft will still have user manuals and sample code for the old module, so you ought to be able to get it running.

I realize this is a college course, but I've done a great deal of serial communications work professionally and the best money I ever spent was on a Stratus Engineering "EZ-Tap". You can eliminate quite a bit of the "error" part of Trial and Error with one of those little devices.