What kind of output is best for controlling the power to a DC motor?

Open-collector outputs with circuit protection are the best choice for controlling power to devices with highly inductive loads such as DC motors, solenoids, and high-current relays.

Switching off inductive loads can induce a voltage spike capable of causing damage to relays, digital outputs, or the DC motor itself.

Both SeaI/O-530 and SeaI/O-540 modules have isolated open-collector outputs with integrated flyback diodes. The flyback diode provides a high level of circuit protection against the voltage spike damage caused by switching highly inductive loads.