DPRD_DAT and DPWR_DAT in optimized block access

Hi,

I have an old project, using a PN device that I would like to migrate to optimized block access. The former block had structures of status and control words, that are also structures of bits.  As far I know this won't work when I change to optimzed access.

Question: Is there any special guideline on how this comm. block should call the DPRD_DAT and DPWR_DAT. I took a look into SINA_SPEED wrote by Siemens, it uses arrays of word. Is this mandatory - does it has to be array of word? Or it could be a structure of word...word/dword...whatever?

In the pic, you will find the actual struct of PO and PI, send and receive buffer, respectively.

Marko Bursic

Question: Is there any special guideline on how this comm. block should call the DPRD_DAT and DPWR_DAT. I took a look into SINA_SPEED wrote by Siemens, it uses arrays of word. Is this mandatory - does it has to be array of word? Or it could be a structure of word...word/dword...whatever?

if I've got you correctly...

DPRD_DAT/DPWR_DAT....  at output/input can be ANY data type and "optimized" variant should work too.

BR

You have at least two options:

- Use the DPRD_DAT to directly write to the datablock containing the data in readable format. I don't think anything prevents this.

- Use the DPRD_DAT to write the data to a bytearray and then use Deserialize command to move the bytearray to your DB structure. And when you want to write data to the PN device, use Serialize to convert the content of your DB structure to bytearray and then use the DPWR_DAT. The serialize / Deserialize command will consider the data in non-optimized format, even if the data is in optimized location. So serializing a Struct containing Bool, Word, Byte, Bool, Byte from optimized location to any bytearray will take 8 bytes. (1:st word contains the one boolean, 2:nd word contains the Word, 3:rd word contains Byte and Bool and 4:th word contains the last byte).

The help from DPWR_DAT mentions that UDP data types and structures are supported.

Marko Bursic

Now I came to odd situation.  I have opened a FB created by Siemens. It is an optimized access and guess what, it uses an UDT structure with Udint, byte, bool,...the bool are multiples of 8, but no serialize / deserialize or gather/scatter is used. Simply the whole structure is passed to DPWR_DAT.  

 That's exactly what i was trying to suggest you earlier.

Hello,

I expect compatibility as priority.