Siemens S7 OB errors

Hi, I am programming a large motion and PLC system using Siemens Step 7 and an S7 300 CPU. Have been trying to figure out a good way to create alarms that tells me a specific remote I/O rack has failed. I have installed OB86 in my processor, but am having a difficult time trying to figure out how to display an alarm on my WinCC station that tells that a specific rack number has failed. I am only asking how to set bits that tell me that the rack is faulted, adding the alarm itself is easy. The Siemens documentation is so obtuse about everything and you have to pour through approx 5325 pages before you find any meaningful information. Havent been able to find any example code I can use as a model.

Want to build this up to the point were the OB's are actully functional, and I think once I get this first one going then I can build on that.

Thanks!
Debbie

Debbie,

You might be better off using one of the pre-written Siemens functions that are available to do what you want.

They are FB125 or FC125,

This thread (Click here) is about the said functions.

Or if you don't want the extensive diagnostics that the functions give you, you could use SFC51, there is a sample code in that thread which will tell you which nodes haves gone down. All you have to do is map the memory bits you use to your alarms.

Paul

Debbie,

In case you are interested in FB125 or FC125....

Here's a link to where you can download them

Paul

Thanks for the info. I didnt know that SFC51 existed. I will give it a try tomorrow. I have investigated using FB125, but didnt like the fact that they didnt add any alarms in the enclosed WinCC project. I think now I could integrate the screens they provide, but want the alarms as well. Again Siemens documentation and help files are very difficult to find good info, and sometimes there are not enough hours in the day to figure out some of these details.

But again, thanks I will give the SFC a try!

Debbie,

The code I posted in the other thread assumes the use of an intergrated DP master (i.e 315-2DP), if you are using a CP card as the DP master then the SZL_ID pin needs to be W#16#4692

Paul