TIA V15, can't turn on retain option in separate DB address.

This reply is strictly about the note you posted, and the first part where you say you do not need the optimizing access.

Sadly, you have it backwards, and I can easily understand why, since you probably come from the classic Step 7 and S7-300/400 world where this is just the way things were done.

The default should be "I do not need non-optimized access for DBs" and unless otherwise directed, DBs should be configured as optimized.

There is a performance benefit to using optimized DBs. Your programming will run faster at no cost to you except the flexibility to use certain blocks or allow certain hardware / software to remotely access your DBs using the older technology.

What I do, and I believe others on the forums do as well, is configure nearly if not all process related DB data as optimized. 

For communications blocks, or use HMIs that do not speak optimized DB access, or have remote PLCs / SCADA or other software remotely accessing data, I configure a special non-optimized DB or set of them that are configured to allow remote access if required.

Another thing to consider if you have not already is to avoid using M-tags.  Even M-tags are slower than optimized DB access, something until somewhat recently I was completely unaware of.  In newer Siemens sample projects, they often have a DB where tags that would have traditionally been M-tags are set up.

I recently reviewed an example Siemens project that had no M-tags in a 1200 / 1500 combo project.  Instead, they had an optimized DB named "tags", and in there is where they inserted all the tags for the project.

Hopefully this is useful information.

Msorich

...

Note: I don't need optimizing access for DBs. Because I feel myself and customer as well very comfortable with absolute addressing and there are couple of significant reasons else, to not use optimizing access for DBs.

Could someone shed light on this matter?

Thank you in advance!

Msorich

Mso,

I routinely transfer data between a PC and PLC using S7-1200 / S7-1500's at a very high update rate, on the order of 4kb to the PC 25 to 5000 Hz (depending the PLC), and from the PC to the PLC at up to 100 Hz.  We can go faster from the PC, but it has so far not been needed.

I use non-optimized data for the to/from DBs.

The PC has no access to any other data than what is exclusively set aside for it.

Msorich

huggy_d1

The default should be "I do not need non-optimized access for DBs" and unless otherwise directed, DBs should be configured as optimized.

 There are couple of significant reasons.

• customer's demands;

• ???

  huggy_d1

  For communications blocks, or use HMIs that do not speak optimized DB access, or have remote PLCs / SCADA or other software remotely accessing data, I configure a special non-optimized DB or set of them that are configured to allow remote access if required.

   So I'm currently in search of certain programm structure/configuration. It needs to connect succesfully high-level laanguages code with TIA code and so forth.
  

  Msorich