Best way of sending data between PLCs via Profinet?

[uptown47]

Hi all,

I've only worked on Profinet once before to talk between a few S7-300 PLCs.

I managed to get the system communicating by using the "GET" and "PUT" commands. Basically I put a datablock on the 'source' PLC and another datablock with the same structure on the 'destination' PLC and then just run "GET" / "PUT" every second or so to transfer information between the PLCs.

I wondered if there was a better way of doing things?

Or is that the only way of transferring data?

Is there not anything like a DP Coupler where you can set up addresses that will be transferred between PLCs?

Thanks for your help

 

[JesperMP]

PUT and GET are very simple to implement.
The drawback is that the PLC reads from and writes to directly in the partner PLCs memory.
Especially the writing to can be dangerous. A typo can cause big problems.

Alternatives:

Send data as Profinet IO where one CPU is Profinet IO Controller, the other is Profinet IO Device (I-Device). Very fast and reliable once set up. Quite easy when you have got the grasp ofn it. Drawback is that it is inflexible, and any change require a restart.

Send data as Profinet IO where both CPUs are Profinet IO Controllers. There is a PN/PN coupler between the two CPUs. Safest way to do it. The networks on either side are really sepatared from each other. Apart from that same as with I-Device.

Send data as send-receive.
Basically, the connections have to be setup on both CPUs.
There are many variants. Easiest is to use the BSEND and BRCV blocks.

 

[uptown47]

PUT and GET are very simple to implement.
The drawback is that the PLC reads from and writes to directly in the partner PLCs memory.
Especially the writing to can be dangerous. A typo can cause big problems.

Alternatives:

Send data as Profinet IO where one CPU is Profinet IO Controller, the other is Profinet IO Device (I-Device). Very fast and reliable once set up. Quite easy when you have got the grasp ofn it. Drawback is that it is inflexible, and any change require a restart.

Send data as Profinet IO where both CPUs are Profinet IO Controllers. There is a PN/PN coupler between the two CPUs. Safest way to do it. The networks on either side are really sepatared from each other. Apart from that same as with I-Device.

Send data as send-receive.
Basically, the connections have to be setup on both CPUs.
There are many variants. Easiest is to use the BSEND and BRCV blocks.

Thanks for the info Jesper. Much appreciated.

I like the sound of a PN/PN coupler as it means I don't need to mess with existing IP addresses etc (I presume it works like a DP/DP coupler).

I'll do a bit of Googling on it and see how it works.

Thanks again for your help

 

[cardosocea]

Also worth mentioning that you can use multicast for one to many communication.

One somewhat important aspect of the GET/PUT is that it doesn't require processing on the receiving end of the function. So GET and PUT functions will happily work on a stopped PLC.

 

[uptown47]

Also worth mentioning that you can use multicast for one to many communication.

One somewhat important aspect of the GET/PUT is that it doesn't require processing on the receiving end of the function. So GET and PUT functions will happily work on a stopped PLC.

Thanks Cardosocea. I've not looked at the multicast functionality. Good point about GET/PUT as well! That certainly is a consideration, now you mention it, for this application.

Cheers