Sudden Loss Of Parameters in S7300

Dear All,

I am working with S7 300 315-2PN/DP PLC in one of my project. The machine was running good from few months after commissioning. While machine was running suddenly the machine stopped. When again attempted to start the machine it was not starting, checked in the data blocks, all parameters were reset to zero or say lost. I again reloaded the parameters in the DB and started the machine.

Why the parameters were lost during running CPU? There was SF on the CPU. But went after some time.

The CPU have G120 drives (40nos) in the topology. The protocol is TCP/IP. One HMI KTP1000 and one OS.

Regards,

Vinit Mate

Hi,

Have a look at the SIMATIC S7-300 CPU 31xC and CPU 31x: Technical specifications under chapter "5.1.3 Retentivity of memory objects".

The retentivity options are different in CPU firmware versions as you can see in the manual. Check out the referenced pages in the manual to find out what caused the data loss. 

You can also upload the diagnostic buffer of the CPU so we can have a look at what could cause the issue.(Reset/PowerOFF/MemoryReset)

Keep in mind the "NON-Retain" property in DB's in question.

I hope I could help!

 Hi,

I have studied the manual. I have found that there is a option in DB to have retentive memory or to have non retentive memory. I checked my program and found that the DB is con figured for retentive operation.

What can be another reason?

Regards,

Vinit

MicroMan

Hi,

Have a look at the SIMATIC S7-300 CPU 31xC and CPU 31x: Technical specifications under chapter "5.1.3 Retentivity of memory objects".

The retentivity options are different in CPU firmware versions as you can see in the manual. Check out the referenced pages in the manual to find out what caused the data loss. 

You can also upload the diagnostic buffer of the CPU so we can have a look at what could cause the issue.(Reset/PowerOFF/MemoryReset)

Keep in mind the "NON-Retain" property in DB's in question.

I hope I could help!

Hi,

Memory Reset? See these FAQ's for explanation:

Retentivity behavior of S7-300 CPU 31x and complete devices C7-6xx with MMC

What is the effect of the STEP 7 function "Copy RAM to ROM"?

An other thing to keep in mind: User Program can also effect values in DBs (for example: Initialisation of DBs in StartUp OBs, Parameter Restore options on HMI etc...)

So study the SIMATIC S7-300 CPU 31xC and CPU 31x: Technical specifications manual carefully and analyze your user program, to make sure the retentivity is working on the way your client wants it.

I hope I could help!

MicroMan

Hi,
...

An other thing to keep in mind: User Program can also effect values in DBs (for example: Initialisation of DBs in StartUp OBs, Parameter Restore options on HMI etc...)

...

 https://support.industry.siemens.com/cs/ww/en/view/18645578

https://support.industry.siemens.com/cs/ww/en/view/837001

Best regards,

Hristo Mihalev