Hi,

If DB contains and array and is not "Only store in load memory". It is transferred from Load to Work memory on startup so two copies exist.

One of the array elements value is changed in the DB in Work memory.

Is it possible to update the array element value in Load memory? In other words, it is like SRCBLK and DSTBLK are the same in WRIT_DBL with source being Work and destination being Load? 

The reason I'm asking is that I have to read 10 random array elements at a time and since READ_DBL from DB with "Only store in load memory" attribute is asynchronous, I have to monitor Busy tag before reading next. Makes it more difficult than reading from DB in Work memory.

Thanks

Hi,

if I understood this correctly, yes WRIT_DBL/READ_DBL is the same as the old instructions.

You can write and read data to/from an datablock with attribute "only in load memory".

But be aware that a heavy amount of write/read actions, especially when its performed every cpu cycle, can "kill" the memory card quite quick.

So basically you should store the data in a seperate data block and transfer all of it in a less frequent interval. Buts up to you.

How do you calculate the service life of a memory card of the S7-1500/S7-1200 and ET 200?

"

In the case of intensive usage (recipes and archives, for example) you can evaluate the service life information of your SMC and replace it accordingly at a defined time as part of your maintenance schedule.

The blocks listed in the table below have read/write access to the SMC:

regards

sancruz