Connecting Client device support Modbus TCP/IP in WinCC V7.0

Hi everyone,
I used to use WinCC V6.x before, now i know that WinCC V7 supporting driver Modbus over TCP/IP. But i haven't inquiried WinCC V7.0 yet, so i wonder that it is ok if i connect all my devices support modbus over TCP/IP to a switch and my computer connect to the switch too. WinCC V7 is istalled in the PC. I have some questions as below:
- My WinCC V7 project can connect directly to client devices support Modbus TCP/IP without via S7-300 or S7-400?
- If not, are there any sulution? and the devices can be add to connect WinCC V7 to client device support modbus over TCP/IP?

I ask these questions because my currentcostomer's project uses Simatic Step7 from CPU315-2DP and the CPU can't expand any more I/O or CP card so i can't add CP341 to the rackto connect to Modbus serial decive(if the devices support modbus RTU or ASCII). The distant from the subststion to the WinCC V7 station is about 2km.

I am looking forward to hearing from you soon

Thanks and best regards,

NTV