FE terminal

What"s the use of FE(functional earth) terminal

*I mean lots and lots of LOGOS works without it but some how must means something...

Thank you

If i have just one LOGO,then i have only one such terminal,so we just wire this to the ground?

As far as i know,its good enough to wire the sheild of a sheilded cable to PE ,so whats the use of FE?

I agree with what you say,we carry the signal all the way to its final destination and we connected it (after say 60 meters) to PE and not to FE,is there any difference?

*of course must be but still its not clear to me 

The FE terminal connection for the LOGO plc is only used at the side from the network connection.

For normal operation the LOGO PLC does not need it.

The reason to use it is clearly incase non shielded cables are used or the RJ45 connector does not have a shield..........

As IXO65 already stated the network need to use the ground as a reference.

Yes i also have seen many installed without the FE terminal connection and basic cables used. In all some cases the communication failed from time to time. Simple installeing a ground wire to the FE terminal solved al problems.

Personal in my house i use seven LOGO plc's wired in the same network as the home computers smart TV , printer ETC. i did not install yet the FE terminal to the ground and i do not have problems. But i used high quality cat 6 cables all shields connected to ground at the two switches and only the short patch cables are not shielded.