S7-400 CPU 416-5H PN/DP EXT FAULT.

Dear Experts,

  Well i am working on CPU- 416-5H redundant cpu. And during my internal test i forced one DO.  during that time i wanted to change my master CPU by putting it in stop mode.

  when i do that my CPU changes the state  ,  secondary CPU becomes master but the primary CPU shows EXT FLT.   as well as SYSTEM FAULT.   even all IM stations shows SF.  

I resolve the problem by memory reset and downloading backup again.  but i want to know why this happens ?    is this because of FORCED  DO ?? 

Thanks,

Pratts23.

Hi,

Forcing DO should not cause any EXTF OR SF. Could you upload diagnostic buffer

Vijay

Pratts23

Dear Experts,

  Well i am working on CPU- 416-5H redundant cpu. And during my internal test i forced one DO.  during that time i wanted to change my master CPU by putting it in stop mode.

  when i do that my CPU changes the state  ,  secondary CPU becomes master but the primary CPU shows EXT FLT.   as well as SYSTEM FAULT.   even all IM stations shows SF.  

I resolve the problem by memory reset and downloading backup again.  but i want to know why this happens ?    is this because of FORCED  DO ?? 

Thanks,

Pratts23.

 Hello,

Do not treat the CPUs during force as if they are in normal work

Force Values shall be used for debugging and testing purposes but not for normal work

During using Force Values you shall watch out  and do not change the mode of CPUs especially when using redundant configuration

What happened with me and a lot of people who had the same experience was:

When switching one CPU to Stop mode and the other becomes master we were not be able to make the stopped CPU enter Run again Except when removing force

I hope this helps

 Hello ,  

 you are right,  even i was not able to bring the stopped cpu to run again.  

thanks,

Pratts23.

Dear Experts,

  Well i am working on CPU- 416-5H redundant cpu. And during my internal test i forced one DO.  during that time i wanted to change my master CPU by putting it in stop mode.

  when i do that my CPU changes the state  ,  secondary CPU becomes master but the primary CPU shows EXT FLT.   as well as SYSTEM FAULT.   even all IM stations shows SF.  

I resolve the problem by memory reset and downloading backup again.  but i want to know why this happens ?    is this because of FORCED  DO ?? 

Thanks,

Pratts23.

 Hello,

Do not treat the CPUs during force as if they are in normal work

Force Values shall be used for debugging and testing purposes but not for normal work

During using Force Values you shall watch out  and do not change the mode of CPUs especially when using redundant configuration

What happened with me and a lot of people who had the same experience was:

When switching one CPU to Stop mode and the other becomes master we were not be able to make the stopped CPU enter Run again Except when removing force

I hope this helps

N. Vijay

Hi,

Forcing DO should not cause any EXTF OR SF. Could you upload diagnostic buffer

Vijay

 Hi ,

You are right my friend ,  Forcing DO should not cause EXTF.  But this faults getting generated when you try to switch the CPU and check the redundancy test while the DO is Forced.

I donot have the Diagnostic buffer now,  but i have seen it and the error was :  CPU-1 LINK UP  ERROR.

thanks,

Pratts23.

Hello,

As explained by Ibrahim, The FORCE function is part of "testing and commissioning functions". These functions inhibit link-up and update. So, you should disable FORCE functions before you proceed to put CPUs in redundant mode.

Table: Properties of link-up and update functions

Best regards,

H-H

H-H

Hello,

As explained by Ibrahim, The FORCE function is part of "testing and commissioning functions". These functions inhibit link-up and update. So, you should disable FORCE functions before you proceed to put CPUs in redundant mode.

Table: Properties of link-up and update functions

Process	Link-up	Update
Execution of the user program	All priority classes (OBs) are processed.	Processing of the priority classes is delayed section by section. All requests are caught up with after the update. For details, refer to the sections below.
Deleting, loading, generating, and compressing of blocks	Blocks cannot be deleted, loaded, created or compressed. When such actions are busy, link-up and update operations are inhibited.	Blocks cannot be deleted, loaded, created or compressed.
Execution of communication functions, PG operation	Communication functions are executed.	Execution of the functions is restricted section by section and delayed. All the delayed functions are caught up with after the update. For details, refer to the sections below.
CPU self-test	Not performed	Not performed
Test and commissioning functions, such as "Monitor and modify tag", "Monitor (On/Off)" and "Force"	Test and commissioning functions are disabled. When such actions are busy, link-up and update operations are inhibited.	Test and commissioning functions are disabled.
Handling of the connections on the master CPU	All connections are retained; no new connections can be made.	All connections are retained; no new connections can be made. Interrupted connections are not restored until the update is completed
Handling of the connections on the reserve CPU	All the connections are cancelled; no new connections can be made.	All connections are already down. They were cancelled during link-up.

Best regards,

H-H

 Hello,

Thanks H-H ,That was helpful.

Thanks,

Pratts23.