Modbus TCP questions (in Siemens 1200)

[Noe]

I have been commisioned to find a way to communicate an Advanced HMI VB.net project we actually have in communication with 5 rockwell PLC's, to add a new machine with a Siemens 1200 PLC. We have to read and write an integer variable and a couple of strings. If possible, I want to use the same controls: datasubscriber and its evets like data changed for the integer (string will be read and written by code).

Is it possible on this protocol?

Sorry if this is a noob question, I am just starting with Siemens and never used Modbus before.

[Noe]

Ok, just found out the answer here in the forum about strings read and write. Not possible directly, but through data conversion from and to integer.

 http://advancedhmi.com/forum/index.php?topic=1301.msg6918#msg6918

Still looking to know if I can use the data changed event of a data subscriber for an integer variable...

[Noe]

In the PLC side, should I use MB_CLIENT and MB_SERVER commands?

[Friedrich]

Don't know much about Siemens, but when I use ABB with AdvancedHMI and ModbusTCP I set the ABB as Modbus Server.

[Noe]

Thank you. A collegue got it working finally, but now I am working on how to read and write 8 bit registers (a char variable).