IEC Protocol

Mike J

Hi all

Before deciding for S7, take in consideration its limits. Contact theresponsables in the link provided.

For electrical system - IEC61850 is today mainly used for protection and control in electrical substation -events occurs in miliseconds.
IEC61850 is not a polling protocol, butuses aserver-client scheme:

Server (IED or protection device) sends data to client (ex.: Sicam PAS or automation system) via reports, when changes in information statusoccurs . If changes are fast, these reports tellsexactlyeach change with timestamps, so you never lose events even when several informations changes really fast, and by fast I mean 1 ms.
Opposed to polling protocols, IEC61850 does not send all data all the time, but only detailed information on what changed.

I thinkthis block for S7 is base on polling protocol (just like Profibus os Modbus): S7 reads data cyclically from equipments, and here problems occurs. If S7 reads data at one instant and 500ms after reads againg (polling cycle), everything that happened during thistime are lost!!! Andfor electrical system events occurs in some miliseconds.
Normally the protection device is capable of registering these fast events properly, but if S7 cannot read it, it can be critical.

Of course it all depends on what you want or need.

Mike J