Every system needs an interface to connect to its environment. Interface specifications depend on complexity level, timing constraints, and robustness requirements.
Board level products (ICs, Modules) are using logic-level signals (PWM, Step/Direction) or simple busses (I²C, SPI, UART). Standalone systems (Modules, Drives) are remotely controlled or configured over field busses like RS232, RS485, USB, CAN or EtherCAT.
A single bidirectional interface for both motion commands and diagnostics keep the count of required lead traces low. Only one low-speed SPI interface from the microcontroller enables extremely miniaturized and lean designs.
The SPI Chipset allows full control over microstepping tables and a seamless change of microstep resolutions on the fly is possible. For optimized motor requirements the microstepping tables are adaptable in the motion controller.
Step and direction (S/D) drivers and motion controllers simplify the control of stepper motors.
Step and direction interfaces are widespread in industry and thus allow for compatible solutions. Especially at high microstep resolutions and high step frequencies S/D architectures reduce required bandwidth compared to SPI or PWM interfaces. SPI is used for setup and feedback channel for diagnostics down to the power stage.
EtherCAT is optimized for realtime transmission of process data and is transported directly within the Ethernet frame thanks to a special Ethertype. It may consist of several EtherCAT telegrams, each serving a particular memory area of the logical process images that can be up to 4 gigabytes in size.