Hello,

I just started on an existing Step 7 classic (v5.5, sp4, hf8) project.

All blocks of the offline and online versions have the same time-stamp and the machine is operational.

When the block consistency check is performed, it gives errors (see attachment) on instance DB's which are based on FB's that don't exist.

For example, the Simatic manager "type" column shows for DB1943: "Instance data block for FB 3093", while FB 3093 doesn't exist. Apparently FB 3093 was renamed in the past to FB 1093.

So I deleted all the faulty iDB's and created new ones, based on the correct (renamed) FB's. I also entered all "Actual values" manually, by using the values of the original (faulty) iDB's. This solved all consistency errors.

Once I downloaded and replaced the iDB's, the machine was no longer operational.

My guess is that in the mean time, the iDB's contained some (new) values/setpoints, so I downloaded the original (faulty) iDB's and everything seemed to be fine again.

My question is: What is the correct procedure to replace the faulty iDB's with the correct ones and still keep all values for the machine to be operational?

Thanks in advance.

Hello,
instance DBs are the runtime memory of FBs. You can't replace them during runtime. A re-start of the CPU is required. It is rather dangerous to replace IDBs with other versions you downloaded from the CPU without re-start, you won't know what will happen.
You should only load "empty" IDBs (they may contain some static variable) and then restart the CPU to get a defined state.

Regards,
Kaulquappe

Thank you Kaulquappe.

For the record:

I stopped the CPU by setting the switch to STOP, downloaded the corrected iDB's and restarted the CPU by setting the switch to RUN.

Everything works fine now.

Hi J. Hollemans,

You have performed correct actions. In addition, u can also use 'Reorganize' for your project. Best thing is 'save as' with 'reorganize slow'.