I have attached a simple CAN demo model, where I am sending CAN signals from a TI 280049 LaunchPad and receiving these signals on a TI 28379D LaunchPad. The CAN terminals on these two launchpads are externally connected using jumper wires. See the attached images.
Note: For building a model on the MCU directly from PLECS, only one launchpad should be connected to the computer at one time. However, once the models are uploaded, you can connect multiple launchpads to the external mode at the same time.
Hope this helps!