S7-1214C. DIAG LEDs Blinking in Modules

If you do not configure your remote PLCs / slaves as "optional", if any of the s7-1214's go offline, the main PLC will go to stop mode.

Also, you want to add the proper OB to run when devices come back with diagnostic errors, like being offline. That may be enough to keep your plc from going into stop mode.

Java_usuario

Hello,

We have one S7-1500 CPU acting as Profinet Master and many S7-1214C CPU as Profinet Slave. We configured last year all the CPUs and tested them in FAT.

Now we are in SAT and only one of the S7-1214C has the following error. The CPU is in STOP and all the modules (2 x CM1241 and 2 X SM1221) have the DIAG Led blinking. We are not able to explain why happens this situation. During the FAT, all the S7-1214C CPU were well programmed and configured and there were no erros, all in RUN state and no LEDs blinking. The remote access to these CPUs is limited, therefore we can not use TIA Portal to make the diagnostic.

Why are these LEDs blinking? How we can detect which is the problem without using TIA portal?

Thank you.