How can we use this S7NT driver with VJC SCADA to communicate with Siemens PLC and do we need to purchase any license for this.
S7NT driver is used to communicate over Ethernet with either the S7-300 (via CP 343-1 module) . In the PC you can use a standard Ethernet card and the Siemens Softnet S7 software. You configure the communication settings for the S7 communication in the Siemens COML S7 and the Siemens "Setting the PG/PC interface" utilities. You can also use S7NT driver to communicate Siemens PLC over MPI & Profibus protocol but you need licensed Siemens Softnet S7 software.
I have also attached the S7NT driver help file for more details on configuration and required details for your reference.
This S7NT Driver is included in free drivers that comes along with Citect Software but you need to purchase separate Siemens Softnet S7 software.