Hi,

We have an existing installation of 2 x Citect SCADA PC’s communicating with 3 x S7 PLC’s, via Profibus, using S7 protocol, with CP 5613 A2 and SIMATIC NET V6.2, on Windows XP. This is working fine.

We have upgraded the SCADA PC’s as follows:

New PC’s (Dell Optiplex 9020)

Win 7 + SP1 32 bit

CP 5623 (PCIe)

SIMATIC NET V12 + SP2

We have the upgraded system running and communicating, but we have intermittent communication errors occuring. These errors sometimes occur a few times an hour or sometimes a few time a day. In between when the errors occur, the system seems to be working fine.

Some of the error messages are shown in the attachment. Note that the error messages are not always the same. Sometimes no error message is displayed.

When the error has occurred and I go to the Network diags, see the attachment for what is displayed. Note that the error messages are not always the same.

To get the coms working again, the PC must be rebooted.

This is happening on both of the PC’s.

We’ve tried using the old CP 5613 A2 cards, but the problem still happens.

How do I resolve this issue?

Regards

Ross Umbers

Hello Ross,

it looks like a timing problem to me. From all the error messages in your file it was the last one which caught my interest (Data transmission problem of ....).

I dont think that you have a short circuit on bus line, but you should check connectors for corrosion. You said the system was running fine before you started the upgrade. Some connectors might be corroded and have bad contact now and then. Especially if there are changes in ambient temperature.

Other thing you might try is to increase TTR (target rotation time).

Look here about determining TTR: SETTING TARGET ROTATION TIME

regards

Hi,

Due to this problem, we've had to put the old PC's back into service - and they're working fine. Which points to an issue with the new PC's &/or the new software, not the Profibus network.

The problem was happening on both PC's, which are in different electical segments, seperated Optical Link Modules. This indicates to me that's it's not an isolated electical problem.

The 3 S7 PLC's also comunicate with each other over this Profibus network. There has been no problems with this communication.

Even if it was an electical problem, you'd expect that the PC's should be able to automacially revover once the issue is corrected. Having to reboot the PC in this situtation is not accepable.

Regards

Ross Umbers

Hi,

Note that that link to TTR doesn't work.

Regards

Ross Umbers

I have edited the link now and it worked for me

regards

Hi,

We have changed the SIMATIC NET version from V12 + SP2 to V8.1 + SP2 and now it is working fine. We have concluded that V12 + SP2 does not work reliably with CP 5623 or CP 5613 A2.

Regards

Ross Umbers