Doing the "impossible" with S7 DP comms.

[JesperMP]

So far it looks pretty good.
Am waiting anxiously for the next step.

 

[PLucas]

Jesper

The plot thickens...

When I tried out the second stage of your second step, that is create a project with the 412 and add a 'dummy' 315 in netpro, configured in netpro correctly. compiled it OK, with the exact same warnings as received in the first project I tried today, which worked OK. I downloaded the 412 only (obviously as the 300 had already been configured as a standalone and communicated all ok). Again I opened the VAT table in the 315, but no data was being written. I have compared the 412 configuration in the first project to the configuration in the stand alone project and I cannot see any differences, but there is no comms at all. Now that doesn't make sense to me. What I am going to try and do is get hold of a different 315, hopefully one of our earlier ones, configure that as a stand alone PLC, not make any changes what so ever to the 412 and see if I can get comms with the new (old) 315.

I will also zip the three projects up and email them to you, then we can see if you can spot the difference between the 412 configuration.

The three projects are:-
project 1 - 412 and 315 in the same project, downloaded from the same project. Comms established
Project 2 - 315 as a stand alone. Downloaded to the 315 after a memory reset. Comms established
Project 3 - 412 as a stand alone, with a 'dummy 315' in the same project, 315 configured correctly in hardware setup, otherwise no connections can be set in netpro. Downloaded 412 only, no comms!!

Paul

 

[PLucas]

Jesper (and anyone else who is following this thread)

This morning, (hey, I was in early.. 06:00hrs, far too early really), I reloaded the 412 configuration from project 1, checked that I had comms with the 315 configured as in project 2. Comms were OK.

I got hold of a different 315 (6ES7 315-2FA03-0AB0 V2.1) and just configured that as a stand alone PLC, again networked via profibus, but nothing hanging off the network. Downloaded the configuration to the PLC plus a DB for writing to. Plugged the profibus cable in and away we went.. we have comms. Just to make sure that the 412 would talk to the 315 (old) I powered the 412 off then back on again, comms came straight back up. I then powered the 315 off and back on, same result, comms working all ok!

I still find the behavour of the 412 confusing, configured as in project 1, it talks to anything (well, at least two different 315's), but configured as in project 3, no joy!

So now I have one 412 and two 315's to play around with, the 'old' 315 I removed from a project that I am woking on at the moment, I will have it in my office till Friday, then I will have to put it back where I 'nicked' it from.

Paul

 

[JesperMP]

Not sure if this is relevant, but I have found a difference between the three projects.

The "S7 Subnet ID" varies like this:
Integrated: 0267-0004
315 alone: 026B-0004
412 alone: 026C-0004

The help text says that one must manually set the S7 Subnet ID when one is not working with a "consistent project".

 

[PLucas]

Jesper

I did notice that difference, but as the 315 stand alone communicated OK, I ignored that little difference, I could give that a try and see what happens.

I will change the subnet ID in the 412 stand alone to match the subnet ID in the intergrated project.

Paul

 

[JesperMP]

You did manually toggle M100.7 to trigger the PUT instruction ?
When it failed, could you see any information at the ERROR and STATUS tabs ?

Also, try to setup an "unspecified connection" from the S7-412.

 

[PLucas]

Jesper

MW100 is assigned to the CPU clock, so M100.7 is the two second pulse. Old habbits die hard.

When the comms failed, i.e no data being written to the 315, the ERROR and STATUS tabs showed zero, no faults.

I had a quick try at changing the Subnet ID, but it was greyed out, I assume that is because the connection is 'specified'.

I will try an unspecified connection later on today.

Paul

 

[JesperMP]

Paul,
you can change S7 Subnet ID by clicking on the purple Profibus line in Netpro.
Only inside the dialog for setting up the connection is it greyed out.

By the way, so far it doesnt look bad, you have comms, also when the 315 is configured as standalone.
"Only" problem is that we cannot figure out why it fails with the standalone 412 project.
Actually I cannot see any difference between the integrated and the standalone (412) projects - apart from the S7 subnet ID.
If we can find the point where the connection changes from good to bad, and it can be reversed both ways. Then I think we have it cracked.

 

[PLucas]

you can change S7 Subnet ID by clicking on the purple Profibus line in Netpro.
Only inside the dialog for setting up the connection is it greyed out.

Another snippet of information gained from this forum. Thanks Jesper, I will try that shortly (nearly time for my 'working' lunch break).

Do you want to go as far as the 'unspecified' connection? Or maybe just figure out why the 412 stand alone doesn't work?

Will your 'main' PLC be a 400?

I'm glad that you are also unable to find any differences between the two projects, apart from the minor one that I also spotted but disregarded, that's probably because I started this on a Monday, not a Friday.. Less likely to make mistakes on a Monday than a Friday

I will report back later on what I have found/done.

Paul

 

[JesperMP]

I have a feeling that an unspecified connection is the most "correct" when the project isnt integrated.

Yes, there is allways an S7-400 in my "standard" project. And it will be natural for it to be the "post office" for all the other smaller parts of the project.

But I am eagerly waiting to hear more about the 315-2PN/DP that was announced a short while ago (the 317-2PN/DP is a bit too pricey for me).
That, and the fact that Softnet S7 Lean will be included in any Win CC Flexible RT license in the future (announced recently) may force me to rethink my entire "standard" setup.

 

[PLucas]

Jesper

A quick update, as my 'working' lunch break was disturbed by a visit from a supplier from Holland, might be another trip to Holland brewing there!! But I have seen the windmills before

Anyway back to the problem, changing the Subnet ID in the 412 stand alone to the same as the intergrated had no effect, still no comms.

I inserted an 'Other station' and set it up as an unspecified connection on Profibus DP, but still no comms from the 400.

Paul

 

[JesperMP]

Hi Paul,

too bad, as it stands it is a mystery why the "integrated" and the "standalone" projects dont behave the same.

I will be on a mission the next few days, so it will be next week before I can look at this again.

 

[PLucas]

I will be on a mission the next few days, so it will be next week before I can look at this again.

No problem Jesper, we can pick this back up anytime you want.

I have learnt something from this exercise, that's always good!

Paul

 

[JesperMP]

Hi again Paul,

I just saw on another (german) forum someone describing doing EXACTLY the same as we are trying to do:

Quote from Max2004 on SPS-foren.de:

Ich habe schon häufiger eine CPU414-3 mit einer CPU314-C ohne DP-DP-Koppler, direkt über die beiden On-Board-DP-Schnittstellen gekoppelt. Beide arbeiten als Master. KEIN PROBLEM! Ich nutze PUT und GET Bausteine. Da ich mit einer Fremdfirma kopple, wurden beide Projekte separat gehalten. Die S7-400 sendet aktiv und liest aktiv zur / von der S7-300 Steuerung. Es ist in der S7-300 keine Kommunikationsbausteine programmiert, sie verhält sich also komplett passiv. Im S7-400 Projekt habe ich eine Dummy-S7-300 hinzugefügt, damit ich unter Netpro die Verbindung einrichten kann.

In other words:
Separate (non integrated) projects.
Using PUT and GET instructions in S7-400 to communicate to S7-300 via the onboard DP ports.
A "dummy" S7-300 has to be inserted in the S7-400 project for the communication to work.

I think that the best is to start all over with a clean sheet. It appears that it can be done.

 

[PLucas]

Separate (non integrated) projects.
Using PUT and GET instructions in S7-400 to communicate to S7-300 via the onboard DP ports.
A "dummy" S7-300 has to be inserted in the S7-400 project for the communication to work.

I am confused Jesper..

Isn't that exactly what I have tried?

The 412 standalone project is exactly that, a 412 with a dummy 315 inserted, the 'dummy' has been configured in Netpro and Hardware editors only, not downloaded not downloaded to the CPU.

We can kick this off again on Monday, I am back to one 315 now as I had to replace the second (old) 315 back in the project, I 'nicked' it from. It would of helped if I had remember to download the original configuration and progam before replacing it.

Paul