Hi,

I am currently performing data transfer between a PLC S-1500 and S-400 PLC (Profibus DP). For this I am using the PUT & GET functions (declared in the PLC S-1500).

When I modify the state of a variable in the API S-1500 (using the function PUT), the PLC S-400 « is aware » after 2 seconds of that change (for now it is reasonable). But when I change the status of a variable in the PLC S-400, the S-1500 PLC « look » the change  49 seconds later (too much !!!)

GET requests are made to « get » data from an DB (size of 2600 bytes) in the S-400. I tried to optimize my program using cyclic blocks and reducing the time clocks. However, the best I have achieved so far is to reduce the time to 9 seconds (even very large !!!) calling my FB from OB cyclic. Supervision will be a huge delay !!!

In a first time, I called my block OB1, but.... doesn't work (huge time)

After, using a OB cyclic, goes better but not enough.

So:

• As I could optimize my program?
• Is there a cyclical block "configurable"?
• The problem is the size of the DB? If so, what can I do? What is the max data that I can "GET" with the GET fonction?

Please see attachement

Thanks for you feedback

Hi ICOMR,

maybe the Data of 2600 Bytes are to much for PUT/GET. Better will be to use BSEND/BRCV-blocks.

PUT/GET is in S7-400 for at least 400 byte and in S7-1500 at least 880 byte. BSEND/BRCV can handle up to 64 kbyte.

See this manual, chapter 32.2 :

CPU-CPU Communication with SIMATIC Controllers

 hope this helps,

regards,

Thanks for you answer,

But, I'm using Profibus DP as communication protocol (I don't have choise). If I'm not wrong, the block BSEND and BRCV doesn't work with Profibus DP. Is that OK?

I can use that blocks (BSEND & BRCV) using Profibus DP?

I made my program in TIA PORTAL (Programme of S7-1500 PLC). Do I have to do the programme NOT in S7-1500 but in the S7-400??

Thanks again

hi ICOMR,

BSEND/BRCV, USEND/URCV and PUT/GET are all for S7-communication, which can be done with MPI, PB and PN/IE. Better you read the whole chapter 32 about S7-communication. 

If you have established a s7-connection, you can use all of these blocks. You don´t have to care about the media.

regards,