S7-400 INTF fault

Hello,

In our batch plant we are using S7 400 CPU (414-3jx04-0ab0) the problem is that while batch running time sometimes 3-4 times in a month the PLC go to STOP mode suddenly and showing INTF fault.If we reset the PLC it resumes.The problem occurs only during the time of two operations either pressing the minor ingredients button or the mixer gate closing time,So is it related to the I/O card if i replace the I/O card the can be sloved.Please advice.

 The best way to find out the cause of error, you need to regularly check and save the diagnostics buffer of CPU and find out the cause of STOP.You also have help information for each event while checking online.In some cases related to programming errors, you are directed to pint of error.If it is CFC or other high level programming, at least you can get related clues.You can share the buffer here for our inspection and we will share our thoughts.

I hope it helps,

hdhosseini

Hello Appuni;

Thank you for the pictures you sent. But you can see that the screen presentation of the buffer is limited, you need to expand the information on each individual message, using the Help on Event button that you see in your pictures.

Basically the buffer shows that at some point a remote IO station has dropped out. We need to know if this applies always to the same station address, and if other messages relate to the same station.

If  I may suggest, using the Save As... button on the Diagnostic Buffer screen will saved all logged messages from the buffer to a text file that you can attach here for us to examine. This will show more details on the errors found by the CPU, and allow us to determine if any of the messages are related to one another.

Hope this helps,

Daniel Chartier

Hello Appuni;

I have taken the liberty of preparing a screenshot of various diagnostic messages that seem to be causing trouble for your CPU, see below.

First, you have recurring errors with a distributed I/O station with address 20, locate that station using your hardware configuration. When it fails, it causes an external fault, lights up a BF (bus fault LED), and, if the CPU cannot locate OB 86 (remote rack failure OB) it will go to Stop. So start by creating OB 86 and downloading it to the CPU, that way (even with no programming inside) it will provide more information in the diagnostic buffer on the cause of the fault, and will keep the CPU running even with the BF LED active.

Next, you have messages that include calls to OB 85 (Programming error OB), and it provoques both internal and external faults in the CPU, causing it to go to Stop.First make sure that OB 85 exists in the CPU program, if not create it and download it to the program; next, check out what output module works with I/O address 200, this is the module that creates the problem, based on the diagnostic messages.

Note that calls to OB 85 are recurrent in the buffer messages, check if they are all related to the same module, or if the addresses change. I can tell you if it happens, but it would be better for you to learn how to analyse the diagnostic buffer messages so you can use it better next time. Identify all modules that are calling OB 85, and see what they have in common.

Hope this helps,

Daniel Chartier.