Hi Friends,

I am in a situation where there are 30 Nos. S7-1200 (All 1214-C DC/DC/DC) on a profinet ring that have to read data( about 4 real values)  from a single PLC to which field instrument has been connected as an AI.

I have spent a lot of time with the PUT/GET instructions, wherein I get a error saying that the connections are faulty because they are of the type Static ISO on TCP etc.. and further that the partner's CPU (all of ver. 3.0) doesn't have the dialog to allow access by PUT/GET.

I am considering the use of TSEND_C and TRCV_C and am now reading up the material. I think that for a TRCV_C instruction in the receiving PLC there must always be a corresponding TSEND_C instruction in the sending PLC. 

There is a limit to the number of connections that could be opened. So my problem is whether the TSEND_C / TRECV_C are appropriate to be used where 29 PLCs line up to demand data from a single PLC!

Please advise me which is the best way to achieve my goal of getting the data from a single PLC into the 29 others.I am not sure that we could write 29 TSEND_C instructions in the sending PLC.

I would really appreciate any help guidance to schedule the communication blocks so that the available resources on the PLCs are not overloaded. 

hi have you tried doing it by communication by i / o device?

regards 

Hello

in the S7 communication guide there is written that you can use pu/Get or Open User Communication. (link)

Here a link to open user com. LINK

But I think It will be a problem of communication ressources of the S71200 (I´m not sure but you will not get more than 8 or something connections??)

Bye Murof

We think we've solved this in the manner described below.

29 Nos. Tsend_c instructions were placed in the PLC that had the data we needed to share. These 29 instructions' were each triggered by their unique Boolean signal named "send_Rqstx" - x=1..29 - placed at both CONT & EN_R inputs of the correspondingTsend_Cx FB.

Each Block's "send_Rqstx" was set when no other block's Send_Rqst was active. Send_Rqst was then reset by OR-ing the Tsend_Cx's "Done" & "Error" outputs.  "Busy" if true> 200ms was also OR-ed to reset the "Send_Rqstx" 

At all blocks, the connections were arranged to be established by the PLCx that had the TRCV_Cx instruction. This way we ensured that only one Comunication could be active at any given time. If any of the blocks were ''Busy" for > 200ms its request would be reset & rest of the blocks could continue.

I request experts here is to comment whether the given approach is ok