For the combination of the FR-A500 + FR-A5NC, Pr.338 and Pr.339 are used to specify whether the external signals or CC-Link commands are used to set the running frequency and start the inverter. If you choose the external signals, you need external wiring.
Since the FR-E520-□□KN does not have a terminal for an external wire (for example, for the start signal), the CC-Link commands are used to start and stop the inverter.