Hello All,

I have to connect S7-1200 with ModScan via (Modbus TCP/IP)

the ModScan is the Server , then i wil to be the client

In my example i try to connect via modscan program ... but unfortunately i got msg connection failed,

i followed several examples in the forum, but still the problem not solved, could anyone please check the attached photos and help me where i do something wrong ?

PLC s7-1200 1214 AC/DC/RLY V4

MB_Client V4

Hello,

Important note, Modscan is always client. It will never act server. So you can not test your application by making PLC as client.

Make PLC as Mdbus TCP server having local port 502 and passive connection. Then try to connect with Modscan software. It will connect.

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Hello,

if you need test your PLC as MB TCP Client, look to some other Server application on web, I like Ananas

DJ_1

Hello,

Important note, Modscan is always client. It will never act server. So you can not test your application by making PLC as client.

Make PLC as Mdbus TCP server having local port 502 and passive connection. Then try to connect with Modscan software. It will connect.

If you feel this post is good then don't forget to rate .

Yes you are right ,,, i have two CPUs and i make one client and the other is Server and everything is working fine,,, 

I have other question... which cases i can use passive connection and when i cant , really i don't have idea what passive connection meaning...

Regards,

Hello,

If you open the TIA portal help for Modbus blocks, its clrealy mentioned when do you have to make passive connection and active connection.

Normally if you want to make PLC as Server then do passive connection. (Active_EST: False)

and when if you want to make PLC as Client then define active connection ( Active_EST: True)

See the attached screenshot.

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