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When should a particular architectural approach be used over another? There are no automatic answers, and sometimes two architectures can be used with success for a given application. In general terms, the more cost-sensitive the application, the more likely it is that designing a card will make sense, and if possible, integrating on-board amplifiers. Using this approach you can choose exactly the connectors you want, and size the card's form factor for your own application.

Highly synchronized systems involving higher power motors, such as machine tools, will gravitate toward either multi-axis motion cards, or increasingly, toward tightly-coupled distributed drives. While not cheap, these drives allow a lot of flexibility in motor type and power range. Since this is a tightly-coupled approach, you will still need to purchase a motion control card for overall path generation, and to coordinate the tiny move segments executed by each drive.

A large number of applications such as medical automation, semiconductor automation, scientific instrumentation, and lowpower general automation, are well-served by loosely-coupled distributed drives, or by multi-axis motion cards. Considerations that push the solution toward distributed drives include larger number of axes, and use of two or more different motor types. Considerations that tilt the solution toward multi-axis cards are the need for synchronization.