Hi All,

I have a weird issue with a S7-1515F, sometimes the CPU goes into error. 

Article Number : 6ES7 517-2UM01-0AB0

Firmware : V 2.8.2

Device Type:  CPU 1515TF-2 PN S7-1500

Has anyone encountered this problem before?

Thank 

Massimo 

Hi massimo_costa

Did you've any infinit BUCLE or JUMP to a previous mark?¿

Hi Willybong,

No Blucle or Jump to the previus mark.

Hi Towome ,

If possible I would like not to update the firmware, because it is a PLC program that has been running since 2020 without problems, and now it gives me this problem.

I checked and the program seems OK.

Regards 

Massimo

You've already defined OB121 and OB122... on your CPU.

Hi!

As Jacek wrote, the problem probably lies in safety part of program. Due to internal structure of safety program, safety program is very "sensitive" about reading data from standard part of program in safety part of program.

To make it short:

I also have had such problems, and it turned out, that the main problem was f.e. changing a value on HMI (something in some DB, or M, in standard part of program) and then reading (using) the same value directly in safe part of program.

HMI communication is asynchrone to main program.

Safety part of program checks values (also from standard part of program)  of things twice in each cycle and if it notices difference, PLC goes to stop (this is a very rough description, simplest as possible.... Maybe someone can elaborate this in details...).

Just check all things from standard part of program, which are you also using in SAFETY program; if any of those things is directly connected to HMI; If this is so, this is probably the cause of your problem.

Have fun and BR!