Q; Should I be able to load a TXT file from the TFL program to the MCsim?
A: Yes it is quite OK to do that. The Text file will be stored on the PC hard drive in a folder that represents the SD card. Visible from Motion Perfect when you type DIR D in the command line terminal.
If the MC400 is to be made visible to the wider network, change its IP addres to 0.0.0.0. Then the external PC that is sending files should be able to connect to the MC400 simulator by using the IP Address of the PC that is hosting the MC400.