This fault did present in four PLCs, to this moment the replacement of PLC is the only solution, but it is not de best solution.

When the "connecting" message appear in the display, we lost all local communication, if we try to connect through cable the PG/PC can not see the controller.

All LEDs of status are off.

On the front-panel display we try to check the address but we can not see that, it is show us "No interfaces have been found"

Apparently the controller lost the communication interface.

and in the diagnostic buffer show like empty

someone have can found the root cause and the possible solutions?

hello,

Have you tried reloading the firmware?

Did you get a response from SIEMENS?

Did you fix this problem?

We have two S7-1511T CPUS with same problem. I have seen a couple of other people complaining the same issue on this forum.

Maybe this should be classified as a known issue for S7-1500 family.

For us Siemens said the product is out of warranty and can not be replaced.

do you have any other idea for solution ?

Havillant Comet

hello,

Have you tried reloading the firmware?

Hi @AniVaz

We have been facing this problem as well. In the last 5 years, we deployed 8 S7-1511T CPU's, out of which 4 have failed with this specific problem. We also have faced this same problem with S7-1513F CPU
Initially, the CPU restarts randomly every 15-20 mins, and within a week the CPU fails permanently with the display showing "Connecting", and CPU unresponsive.

We contacted Siemens Support and they requested service data, which was sent for analysis but unfortunately it wasn't helpful.

Siemens support recommends ordering a special investigation, which we are in process of initiating.

All of our faulty CPU's were firmware version 2.5 and on the recommendation of Siemens Support, we upgraded to version 2.9.4 the latest from Siemens. However, the problem still persisted with the random restart of CPU's and then eventually CPU became completely unresponsive with all Diagnostic LED's OFF and the display showing "Connecting".

 @cnmautomation 

We contacted Siemens Support and sent ours damages CPUs and we are waiting for they answer

cnmautomation

Hi @AniVaz

We have been facing this problem as well. In the last 5 years, we deployed 8 S7-1511T CPU's, out of which 4 have failed with this specific problem. We also have faced this same problem with S7-1513F CPU
Initially, the CPU restarts randomly every 15-20 mins, and within a week the CPU fails permanently with the display showing "Connecting", and CPU unresponsive.

We contacted Siemens Support and they requested service data, which was sent for analysis but unfortunately it wasn't helpful.

Siemens support recommends ordering a special investigation, which we are in process of initiating.

All of our faulty CPU's were firmware version 2.5 and on the recommendation of Siemens Support, we upgraded to version 2.9.4 the latest from Siemens. However, the problem still persisted with the random restart of CPU's and then eventually CPU became completely unresponsive with all Diagnostic LED's OFF and the display showing "Connecting".