View Full Version : SF LED on S7-300

June 7th, 2003, 02:22 AM
I work on S7-300.I download a simple program to CPU314.After putting
PLC in run mode,the SF LED on the PLC turns on.I want to know how can I find my problem?

June 7th, 2003, 07:21 AM
Hello, smb;
The SF LED turning red on Run mode means that something in your download is not acceptable to the CPU. For example your Hardware configuration does not match the actual hardware of the PLC, or you are attempting to access an address that cannot be used by that CPU.
I suggest you use the Diagnostic buffer of the CPU to see what messages are available:
Open Step 7, open the PLC menu, select Module Information: the online CPU info page opens up. Choose the Diagnostic buffer tab.
Cloick on each meessage line and look at the information that is output for it in the bottom of the diagnostic page. Pay special attention to the OBxx that the Diagnostic buffer saya are missing. They are a great clue to the source of your problem.
For more info on diagnostic OBs look at the "STEP 7 - System and Standard Functions for S7-300 and S7-400" manual in the Simatic-Documentation section of the Siemens directory.
Hope this helps,
Daniel Chartier

June 8th, 2003, 10:53 PM
Please check your's configuration in Hardware such as I/O module
(should be correct)
Also,your program before download to PLC step s7-300