Duris_I

Hello,

your question: can we use bsend, brcv functions?

I think yes, no problem but you need to configure send block at one Client PLC and rcv block at other PLC. The question is how much connection resources are available at each PLC, how much data are expected to exchange exactly or how network is set. I think you need all theses things take to account. I recommend check typical BSEND/BRCV FAQs described cfg options and examples.

 Hello,

Yes, Bsend,Brcv functions.

There are 18 PLCs and 1gateway, how can create send and recive data with only one Bsend on a PLC and brecive on other PLC?

I think Gateway and other PLCs should have Bsend and Brcv functions. 

Max data are 6kbyte send to one Client and recive 2kbyte from that, other clients have less data.

Gateway in total  send  and recive 32kbyte with clients and 32kbyte with level2(level 2with opc ua).

Remember that you need to copy all 8000 variables into one single datablock on the S7-400 side, to use BRECV on this data. Depends on how the variables are distributed in the programs of the S7-400 side, I'd think about just using GET blocks and switching the areas you want to get access to. The performance difference is marginal, as BSEND/BRECV uses the same PDU size as Put/Get.

Using BSEND/BRECV is a clearer solution, but takes some work on the S7-400 side. If there are datablocks already available in the S7-400 which are used for some other kind of external access (e.g. HMI), then I wouldn't hesitate just using GET to access the data, without changing anything in the S7-400 programs.

Thomas_v2.1

Remember that you need to copy all 8000 variables into one single datablock on the S7-400 side, to use BRECV on this data. Depends on how the variables are distributed in the programs of the S7-400 side, I'd think about just using GET blocks and switching the areas you want to get access to. The performance difference is marginal, as BSEND/BRECV uses the same PDU size as Put/Get.

Using BSEND/BRECV is a clearer solution, but takes some work on the S7-400 side. If there are datablocks already available in the S7-400 which are used for some other kind of external access (e.g. HMI), then I wouldn't hesitate just using GET to access the data, without changing anything in the S7-400 programs.

m.kh

 Put/get  tranfer small length data, I think not suttible .

 

You can change the any pointer after each get request, you only have to make sure not to split the data between a more-than-one-byte-value to not run into consistency issues. But if you are allowed to modify the programs in the S7-400 stations, then use BSEND/BRECV.