Siemens PLC board for test input /output

Hello all

I have a Siemens S7-300 CPU 315-2DP, CP343-2P and ASI module .AC2459 I want to using it for test input output . as show in below picture

i am new with PLC Siemens and tryed to configuration and and made download project but get error SF i don't know where is the problem

can any one help me

Note : ASI module we already addressing Slave 1

attached plc project that i want to check and correct



Is that SF that you mentionned related to "System fault" that displayed on a LED ...or that dispkayed on PLC communication interface /hmi /PC window..

Are you using PROFIBUS...if yes the re could be kind of error from conffiguration...

Are you sure about the programm that you have downloaded...I mean is there soution to get a compare show any minor /major differences with another programm..

Here some notes from OEM :

A SF appears when the CPU encounters an error (hardware, software, programming, etc...) that it does not know how to deal with. Basically, it means you, the programmer, are doing a mistake somewhere in the program.The SF LED will never turn off until you correct those errors.
Diagnostic OBs are called by the CPU operating system to try and handle the error; different OBs react to different types of error: OB 86 to remote I/O station problems, OB 121 to program errors...
The results of the diagnostic OBs are collected in the diagnostic buffer.

So please open the diagnostic buffer, read the messages logged there and try to understand what is affecting the CPU.
If ypu have a problem understanding the messages, you can SAVE them AS.. and attache the text file here so we can help you out.
Hope this helps,

Thx for clarifying..
thank you for your reply
really , I had a mistake in hardware configuration .
we created new project and corrected the configuration of CP343 model number, then the downloaded No error .