Hello,

If anyone would care to help me, I have a system with two Compact Logix and twelve Siemens 315s. All of the 315s need to continually obtain status data from both Compact Logix. It doesn't have to be blazing fast, something like a 5-second refresh rate would be tolerable. The Compact Logix will be separated by about 800 feet, and the 315s are all over the plant.

I'm thinking the solution will be Ethernet-based, but I don't know specifically how to do it. The 315s are all Ethernet ready, but the Compact Logix processors are not. In the past we have used a Siemens IMAP add-on to make the 315s talk to each other, but not with the Compact Logix, and we're having trouble making the IMAP work at all now.

Any and all ideas appreciated. Thank you.

Dave

I can't find the post tonight, "maybe mikey can help", but I read on mrplc the other day that there are two or three "classes" of CompactLogix. The 4X class supports Ethernet and CNET add on modules to get ethernet, the 3X class has just what it comes with from the factory. To get a 3X on ethernet you need a NET-ENI and then you're limited by the 19,200 serial baud rate.

I don't know a whole lot about Siemens, but Modbus TCP might be your simplest way to share data registers from all I've read recently.

I suspect you'd use the Modbus built into the SIemens and add a Prosoft Modbus TCP card to a 4X compact logix.

This one maybe,(post three) but not sure this is going to help the OP. I think his problem is more about supported protocol.
http://forums.mrplc.com/index.php?showtopic=13932#

As suggested Modbus TCP could be the answer:

You will need some extra software for the S7 (read extra $$$$), have a look at

http://www.industry.siemens.de/IT4Industry...s/proto_mod.htm

Dont know about Modbus TCP on Compact Logix.

800ft is too far for a Cat5 cable. So you will need to consider copper/fibre convertors for the link.

Mike

This is not going to be easy.

As far as I know, iMap is for ProfiNet and not Ethernet/IP. So this cannot be used to tie CompactLogix and S7 together.

And I am afraid that the CompactLogix cannot be brought to speak Modbus TCP.

It would be possible to setup a Profibus connection. There is a Profibus card for CompactLogix from Hilscher. And if the speed is cranked down to 187.5kbps it can reach 800 meters without repeaters.

But what is tricky is that you have to transfer from 2 to 12.

Profibus is a single master to many slaves kind of network. Several master-slave systems can co-exist on the same bus, but they cannot readily transfer data between each other. There are ways to transfer data from one master-slave system to another master-slave system, but even so it is more tricky, and it doesnt give redundancy if the other master-slave system is down for any reason.

You may have to consider to let one CompactLogix collect the data from the other CompactLogis and then let it as master transfer the data to the 315's that must then be slaves.

A drastical solution is to exchange the CompactLogix's for ControlLogix's with EWEB modules.
With EWEB it is possible to communicate directly with an S7 via ethernet "sockets".

Another solution could be to use one or two PCs as datahubs. With OPC servers for AB and S7 and some datatransfer software it can be used to transfer data back and forth as needed.

OK if CompactLogix cannot do Modbus TCP then what about using a Red Lion DSP as a data hub for the 2 CompactLogix, with the DSP talking Modbus TCP to the 12 315's.

DSP will talk DH-485, and so will CompactLogix, OK so its not fast but speed dosnt seem to be an issue.

DSP has Profibus option card, but this is a Profibus slave.

Yes, a "protocol converter" is a solution.

I think that the best would be if the protocol converter could speak what is most native with each PLC.
That would be "S7 ethernet" (aka "RFC1006") for the 315's.
solar controller forget to tell what kind of CompactLogix he will be using. But as there is no Ethernet, then DF1 sounds like the protocol to use.

It ought to be possible. Just be sure to get one that can setup at least 14 connections.

edit:
For example, in addition to S7 protocols Siemens panels can speak both DF1 and Ethernet/IP, so they could be used in theory.
But unfortunately they are limited to max 8 connections.

Gentlemen (and ladies if applicable),

First of all, I want to thank each of you for your contributions to my solution.

We (our controls group) have decided on a workable solution. We will install a new 315 dedicated to the task of communicating with the two Compact Logix PLCs via Profibus (there is a Prosoft Profibus module in each Compact Logix rack). This 315 will then communicate to the remaining 315s via Profinet and IMAP. I understand it is not absolutely necessary to use IMAP to make the 315s communicate with each other, but we already have the licenses so we will make use of them.

Again, thanks for your input.


Dave

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