Retentive real

Hello again! I have an S7-314-2DP processor and I don't know how to save a retentive real variable. The prcessor admits only ex. M0-M16 retentive memory bite, time and counter and DB's are reseted on a power failure.

Please help me.
Thanks in advance.

svoicum said:

how to save a retentive real variable. The prcessor admits only ex. M0-M16 retentive memory bite,

Click to expand...

you can use MD0, MD4, MD8, MD 12 etc as real values (define them in symbol table) and set up those M are retentive...
or use datablock to store real value

In general, the memory (DB and markers) is retentive. As girevik stated, define your DB as real or use MD.

Here is a link to Siemens tech note about the Retentivity of S7-300 CPUs (Entry ID 17602317). It gives details on making memory retentive or not retentive.