Help Request S7-400


Thread Starter


Our PLC has communication with site via two paths, one is via "Fiberoptics Module Profibus"(OZD Profi 12M) and the other is via ET200 S(IM151: 6ES7 151
-1AA02-0ab0). The problem is the IM151 communication failure with PLC, on IM 151 the "SF" LED is lit and the "BF" LED is blinking, on CPU the "BUS2" is also blinking.

I reloaded the configuration file into PLC, replaced the IM151 with a healthy one, even changed the interconnection cable but the problem was not fixed.

I would greatly appreciate if someone can advise me on resolving the matter.
Was it previously working or is this a new install? The SF denotes that there is a hardware configuration mismatch on the ET200S system itself. Open HW Manager and ensure that the part numbers are matched for all equipment on the ET200S rack. Are you sure your IM151 module isn't 151-1AB02 not -1AA02?

Open the CPU diagnostics for more information on the Bus Fault (BF). The address set for the ET200S may be incorrect, are there DIP switches on the device that need to match the number in the HW manager.

Thank you Anonymous for your reply. The system was working properly before this fault. Yes the indications denote that there is a hardware configuration mismatch, but this problem happened suddenly and as I stated before I reloaded the sofware again but the problem was not fixed and no hardware has been changed before and after this failure.

In order to make sure that the hardwares are helathy or not, I replaced the IM151-1,inter-connection cable between IM151-1 Cpu and OP37, and CPU with a new one, one by one. But the problem was not fixed. May I have an email from you to send you the result of the Diagnosis-Buffer to you? I do appreciate your concern and advice.