Have you tried doubling the F-Monitoring time (or increasing it) as indicated by the posted diag buffer entry)?

U_19157521-1b6f-47b7-88d6-39e8be2cc664

Hello,

I am currently on finish line on a project with an S7-1214FC DC/DC/DC (firmware V4.3) PLC which has a SM 1226 F-DQ4x 24V that I use to STO and SSO signal to some VFD, in addition to a safe signal to a Festo air treatment unit. From time to time (about twice per day) I am receiving the errors that are attached to this message. When the erros appear the PLC stays in Run,and the only way to clear the error is by restarting the machine. I have already replaced the module to no avail. Can you provide some feedback about what is causing this problem? Thanks.

From time to time is not a helpful response by itself.

If the original problem generated diag buffer errors 4 times a day and 500ms generates diag buffer errors 2 times a day, that's very helpful.  It lets you know your safety devices are having problems communicating several times a day, often less than 500 ms, but occassionally longer than 500ms.

If you now (for testing purposes only) increased the time to 1000ms and it changes the happening of time to time to 1 time per week - still unacceptable of course - you know a little more about the problem severity.

If you are able to change the Profisafe baud rate, reducing it by 1/2, does the time to time change in any significant way?

U_19157521-1b6f-47b7-88d6-39e8be2cc664

I did, to 500ms. The error still happens from time to time...

You talking about Profibus or Profinet profisafe?

If you are talking about Profisafe over Profinet, baud rate is not part of it.

Using good quality cabling and routing is important whether it is profibus or profinet.

If you run the profisafe cabling outside electrical enclosures / wireways, does the error still happen?

Do you have cable testers capable of fully certifying cable throughput?  If not, I recommend purchasing or renting or borrowing one so you can find out which cable is in need of a better termination, replacement cable, or re-routing, or using metal flexible or rigid conduit.

What electrical noise environment does the cabling pass through?  When the error occurs, does it tell you which device is the source, and is it always the same device?

U_19157521-1b6f-47b7-88d6-39e8be2cc664

Thank you for the explanation. Where can I found the Profisafe baud rate setting?

Hi,

Did you checked if "nothing" are writing safety variables in HMI / standard program?