troubleshooting Siemens Simatic S7-300 PROFIBUS "BUSF" failure

[defcon.klaxon]

Here's an update for anyone interested:

Co-worker went down last Friday and replaced master PLC (CPU 316) with replacement. Local slaves were then able to communicate via PROFIBUS, though remote PLC is still down. This would point to the physical PROFIBUS connection between master PLC and remote slave since he connected to the remote slave locally with the PC Adapter.

We are going to be heading back this Wednesday to try to get the local slaves and PC/PG operational; even if the pump station has to be run manually, if we can get the filters up and running that would at least allow the municipality to draw water from the lake and not rely on their wells.

Latest roadblock is trying to get the existing HMI (Wonderware) to properly communicate with master PLC; it seems like we're reading in data (turbidity from local slaves seems to come up just fine) but when a switch in the HMI is changed and we watch the PLC logic, it doesn't seem to register the change. This is all second-hand from my co-worker as I wasn't there on Friday. If there is anything I should keep in my back pocket when trying to set up the PC/PG interface with the 316, I'm all ears; this connection is through a CP5611 card. What's odd is that when we got there, the connection through the CP5611 was in the MPI port of the CPU (left side connection) but the COMMS Preference window shows the settings as CP5611, PROFIBUS...wouldn't it need to be MPI to connect there? A bit odd, though we're told the HMI screen was operational before the system took a dump so that's just one more mystery.

Fixing this system is like pulling teeth, especially since neither of us have any Siemens experience! We're making small advances in progress though, and that's largely due to your help here so thanks a bunch!

 

[JesperMP]

I dont know what the "COMMS Preference window" is. Is that in Wonderware ?

Is the Wonderware HMI on the said PC with the CP5611 ?
If so, I think there is a possibility that Wonderware uses Simatic Softnet software for the connection to the PLC. If that is the case, you shall look for the "Station Configurator" software on the PC. Notice that in this case, the settings for the PG/PC Interface are NOT used to establish the connection to the PLC.
If the Simatic Net software is installed, post screenshots from the Station Configurator.

In the downloads section of this forum under Siemens, I have posted a sample project for how Simatic Net is setup to establish an OPC Connection to a Siemens PLC via MPI. You can study this to get an idea how Simatic Net works.

 

[defcon.klaxon]

I dont know what the "COMMS Preference window" is. Is that in Wonderware ?

Oops, sorry I didn't use good terminology. What I meant to describe was in Simatics Manager, where you set how the PC/PG communicates to the PLC...it's a window that shows all the various adapter options. I think you refer to it as the PC/PG Interface settings.

Is the Wonderware HMI on the said PC with the CP5611?

Yes it is!

If so, I think there is a possibility that Wonderware uses Simatic Softnet software for the connection to the PLC. If that is the case, you shall look for the "Station Configurator" software on the PC.

Ok great! I will look for that.

Notice that in this case, the settings for the PG/PC Interface are NOT used to establish the connection to the PLC.

Good to know. Is the interface still through the CP5611? Or could that be why they for some reason had the PC Adapter hooked up too? That may be a very dumb question, we're just trying to figure out why they'd have the PC Adapter along with a CP5611 on the same machine.

If the Simatic Net software is installed, post screenshots from the Station Configurator.

Will do.

In the downloads section of this forum under Siemens, I have posted a sample project for how Simatic Net is setup to establish an OPC Connection to a Siemens PLC via MPI. You can study this to get an idea how Simatic Net works.

Thanks so much! Really appreciate it.

 

[defcon.klaxon]

Well, after much work the system has been fixed and it looks like full functionality has been restored. The remote slave at the pump house that wasn't communicating was replaced and once that was done, the BUSF light finally extinguished. Our best guess is that the underground PROFIBUS connections got wet and shorted during the torrential downpour and fried the PROFIBUS comms ports at the master PLC and the pump house slave. The local slaves at the treatment plant seem to be operating so why they survived is anyone's guess.

Many thanks to all who chimed in, especially JesperMP for sticking with me. Gonna go now and purchase a life membership for the forum, as I feel I owe it!