Write directly to the IO through DB

Hello,

I am writing universal plc code for S7-1500 ProfiNet communication to Yaskawa Servo drive (Telegram 100).

I want to Have an DB_Axis which is In/Out to the FB. FB will generally serve like MC block (MC_power, velocity….).

I do not want to write to that DB. I want to write directly to the IO through DB. I want that DB indirectly point to the IO area with ProfiNet Addresses. DB will have indirect addressing to the IO area. When I open DB I will directly read IO. I repeat. I do not want to write to DB somewhere and later transfer it to the IO. I want to write directly to the IO through DB indirect addressing.

It is same philosophy for SIEMENS technical blocks, like standard SIEMENS MOTION technical blocks (Technology object 1ST_AXIS/CONFIGURATION/PARAMETER VIEW or Right click on 1^st_axis in technology objects and press DB EDITOR).

With 1500 and V13 there is no technical objects for Yaskawa drives (telegram100) and I have to make it myself. I know that Siemens is using VREF system Data type but I cannot figure it out how.

Can you help me how to do that? I will have attached my plc code. See OB1 networks NW13 & NW15, read comments. I know it is about Variant VREF….

See also attached image like reference about what I want to have. My DB_Axis will carry all the information related to that servo drive axis. Code has to be universal that my colleague use it in the future like standard Siemens MC blocks.

Can somebody help me?

Sorry. I cannot attach code. Zipped is 4.5MB Allowed is 3000KB.

Thank you,

Regards

Sasa Marinkov

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Split from Requesting advice for indirect addressing M/I/Q Area.

Thanks a lot William.

We followed your instruction and we made what we wanted.

We used PEEK and POKE instructions.

We also used UDT structures.

The clue was :

"The VREF UDT does give us an important clue. ?.AREA, ?.DB_NUMBER and ?.OFFSET are data elements used for PEEK / POKE commands. It is an indirect way to access inputs / outputs / memory / DB."

Thanks again for your help.

Sasa Marinkov

staridjeram

Thanks a lot William.

We followed your instruction and we made what we wanted.

We used PEEK and POKE instructions.

We also used UDT structures.

The clue was :

"The VREF UDT does give us an important clue. ?.AREA, ?.DB_NUMBER and ?.OFFSET are data elements used for PEEK / POKE commands. It is an indirect way to access inputs / outputs / memory / DB."

Thanks again for your help.

Sasa Marinkov

 Came across this very useful post and I thought I'd add a bit more information to help those in the future.  
In my application, I want to go from the VREF information for the interface of an axis TO to reading bits out of the telegram.  As Sasa says above, the PEEK used with the VREF structure is the answer.  BUT, what is true for the Axis TO, at least, is that the OFFSET value is in BITS, not bytes. 

So, you need to divide the OFFSET value by 8 to for the byte offset of the PEEK command.

For your Axis TO it looks like this:

Hope this helps,

Curt Hayes