There are two types of 4-20ma analog input cards. The video showed connecting an analog input where the analog card provides "loop power". In this case, +24VDC power is provided by the PLC backplane. Other types of analog input cards require an external 24VDC power supply, which would be wired as you described. That is why we always caution: before wiring any device, consult the wiring diagrams provided by the manufacturer of your I/O cards for determining proper connections.