WinWedge does not have the ability to calculate check sums or make logical decisions on data. This means that it does not directly support any high level protocols like modbus. It does not mean that you cannot use WinWedge to communicate with modbus devices. You can, in most cases, implement any protocol that you like, including Modbus, using features of the application that will be using WinWedge.
For example, you could use the macro language in whatever program you are feeding data into to implement the protocol, and then simply use WinWedge to do the serial input and output. If you were using a program like Excel, Access, Wonderware, Fix DMACS, etc., you could use the macro or script languages in these programs to calculate any necessary checksums on your data or perform logical functions to control the flow of data. WinWedge would simply act as a tool providing the other application with a way to both send and receive serial data.