hello automation friendz
ur one of pal now a days having very tough time regarding L2DP Error, which is occuring so frequently. can any body tell me why? what the reason behind it. What are the remedies?

 

Hello;

When you say L2DP error, do you mean the SF and BusF LEDs are red on the CPU, and the CPU goes to stop?

If that is the case, you need to diagnose the source of the problem. Add a OB86 block to the program (no need to program it at this time, just create it and download it to the CPU). This will allow the CPU to continue functioning even if the fault occurs, and will load diagnostic data in the Diagnostic Buffer.

Once the fault occurs (with OB86 loaded), you can either open the Daignostic Buffer of the CPU, or go to the HardwareConfig editor, go Online, and look at which slave is marked as defective; yopu can get a limited amount of diagnostics for the slaves.

On top of OB86, for more specific diagnostics of the Profibus network, you can download (from the Siemens website) FB125; set it up and download it as described in the accompanying help file, and ou will get diagnostics and archiving of errors for all your slaves.

The main causes, in my experience, for intermittent DP connection losses, are faulty connections (cable shield loses contact on the DB9 connectors due to high vibration levels, for example), faulty termination (last station loses power, so active termination circuit is no longer powered), or bus design out of specs (speed to high for the length of the network, for example).

Hope this helps,
Daniel Chartier