Fault Message for PLC S7-300-2DP

Configuration problem is what you seem to have, and my suggestion is for you to contact Siemens for support.

Hi there,

With the Siemens S7 rand of PLC's.

If you get the red SF LED - this means you have a programming error. It could be that you are trying to access a periphial area that is not actualy present on the bus.

If you get the red BF LED - one of your DP slaves has dropped off the bus.

Now your specific problem is easy to solve. You have the red BF and SF LED's. Goto the diagnostic buffer, and write down the adress that has the problem (It will tell you something like input adress xxx). Then goto your hardware config. You can then go through each configured station to find your match. From this you will know which DP Node (station is giving you problems). Now you will see if this station is the last in the line or in the middle. If it is in the middle and the stations downstream are not affected - you have a hardware problem (try replacing IM), if the stations downstream are also affected - you have a physical bus problem (loose connection; interferene etc).

For more information download the relevant manuals from:

www.profibus.com

www.automation.siemens.com

Please keep us updated.

Regards,

Craig

dear sir

really i appreciate your answer, but in the uploaded program there is no DP slaves on the profibus network except the cpu, and i will try to get the diagonestic buffer as soon as possible

Also i want to ask if the defected DP node in the last i change on-off termination only

to ommit it from network or i ommit it by software also in addetion to cable

termination change

Hi there,

To ommit the defective node you have to take it our of the hardware configuration and the software and then you can use the termination resistor.

Regards,

Craig