The SERCOS interface is first and foremost a motion control bus, with I/O capabilities. It does not compete with device buses and field buses, which are primarily intended to control low-level devices such as sensors, motor starters and inverters that require on/off control or require an asynchronous command value. However, in some applications the I/O requirements are appropriate to utilize the SERCOS interface as both the motion and I/O interface. Although the SERCOS interface was not designed primarily for I/O, it includes the capability to decentralize I/O via multiple I/O nodes that connect to the field devices. The decision of whether to use a fieldbus, SERCOS interface, or both, depends on the application. If only loose coupling between motion axes is required, a series of single-axis position drives connected via a fieldbus may be adequate. DeviceNet or ControlNet, for example, can be used for simple motion control applications, but they are not truly deterministic and do not possess a clock tick or synchronization signal to ensure that multiple nodes operate in perfect time with each other. Synchronized motion applications require a higher level of realtime control. The SERCOS interface allows the motion control to calculate the position commands for all axes in a servo system and transmit them with guaranteed synchronization to fully coordinate multiple axes of motion. In high power applications, such as flexible machine systems, both a fieldbus and SERCOS interface can exist in the same control.