Hello experts,

I'm trying to solve communication problem between  PLC s7-300 of my client and our PLC s7 1200 .My client uses a CPU315-2 dp (6ES7 315-2AG10-0AB0) with a module CP 343-1 lean to communicate with our PLC s7-1214 (6ES7 214-1AG40-0XB0) through TCP. They need to transfer and receive 2 bytes of data and they use AG_SEND and AG_RECV commands to send and receive this data,but we failed to establish the communication between both plc's. I am trying to understand how will CPU315-2 identify CPU1214 and how will it send the data? How should I configure s7300  to a PLC 1200 in the Simatic manager Netpro? If someone has any sample program to help me? Thanks in advance.

There are a lot of examples.

https://support.industry.siemens.com/cs/document/51101016/how-is-data-with-variable-message-length-transferred-via-the-tcp-protocol-and-received-by-an-s7-300-station-via-the-industrial-ethernet-cp-?dti=0&lc=en-WW

https://support.industry.siemens.com/cs/document/40556214/data-synchronization-with-s7-communication-between-several-s7-1200-substations-and-one-s7-1500-300-head-plc?dti=0&lc=en-WW

and much more if you are using the search - function.

Hello,

I must recommend that Jurgen's first link, this can be very helpful to anyone who need receive variable length message. Good links...

Hello,

if I can answer, this depends to more situations, connection types. In this case you don't need import S7-1200, simply you need create communication to unspecified partner. Another thing what you need accord with your partner is, who will be Client and who Server. This settings you need both define in your own projects. If you'll create S7-1200 side, you probably use your Profinet port of CPU and then use T instructions for communication. Look to TIA help for TCON with corresponding instructions or TSEND_C and TRCV_C instructions.

Hello,

sry, you have told us that they use AG instructions, so therefore I've recommend to you that T instructions, simply you must prepare in this case your user defined communication, accord with partner message format. I think in this case you can't use PUT and GET. If they don't expect use Ag instructions, probably then you can use on your side PUT/GET because their Lean CP can act only as Server with S7 communication, hope remember ok. In case of user defined communication over TCP protocol they can use Ag instructions and you that mentioned T instructions. You both accord message format, set who will be Server and Client, prepare own cfg due this, create communication and can work. Your thoughts? Hope I good understand your situation.

Update: simply Jurgen show you example of S7-300 side, you was curious how it can work, can be prepared (hope understand Juregn's post like that), so I was understand that your side is S7-1200 in case of open user communication over TCP.

Hello,

eeeeeeehm sry, but don't understand that, sry. Simply Lean CP can only act as Server in case of S7 communication not in Open communication. They can easy create S7-300 open user communication via AG_SEND/RECV also as Client, this simply work without problems. They don't need include any of GSD, only define unspecified connection via TCP, accord message format with you and that's all. You will create with your S7-1200 also User communication via your Profinet port and use T instructions as I sugested before, you can be Server without problems. Your thoughts?

Update: sry again, you now want use S7 communication PUT/GET? Probably if you don't want use open user communication with partner, this can be other solution, but never had that situation. Also important question is how much data you want Exchange because of limited amount of data in case of S7, user communication can Exchange much more data.