Dear freinds,

Currently, I am working on a project in which a CPU "6ES7412- 2XG00-0AB0" all its leds are "ON". (see attached pic).

What could be the reason for that?

warm regards.

Tomy

Hi Tomy Master,

CPU is faulty and go through the CPU manual for exact cause.

thank you for reply my friend,

but i have already referred to the manual, but it does not mention any case like this.

besides that i have replaced the CPU (used another another one) on the same rack, but it showed the same all LEDs!!!

Regards.

Tomy 

hi Tomy,

is it possible to access the CPU?

All LEDs are usually on when the PLC starts up.

I guess the PLC can´t finish the start-up-process and you can´t access it.

You changed the CPU, so there must be something in the system that prevents the CPU to start up.

Memory card? Rack? something like this...

Can you change the Memory Card and/or the Rack?

hope this helps,

regards,

Hi,

did you try a factory reset of you PLC?

After resetting, all data will be copied from MMC to working memory. If this will not work, your MMC could be defect (or also PLC).

Please check the following FAQ;:

How do you reset a SIMATIC S7-300 CPU and MMC (default reset or overall reset)?

Regards,

Towome

Towome

Hi,

did you try a factory reset of you PLC?

After resetting, all data will be copied from MMC to working memory. If this will not work, your MMC could be defect (or also PLC).

Please check the following FAQ;:

How do you reset a SIMATIC S7-300 CPU and MMC (default reset or overall reset)?

Regards,

Towome

 

 for a S7-400 better use this :

SIMATIC S7-400 S7-400 Automation System, CPU Specifications

See this manual, chapter 3.4

hope this helps,

regards,

Thank you all my dear friends,

I will try to do what you have told me, and i will provide feedback as soon as possible.

Regards.

Tomy