Embodiments of methods that are useful to avoid overflow in fixed-length buffers. In one embodiment, the methods dynamically adjust parameters (e.g., sample time) and reconfigure data in the buffer to allow new data samples to fit in the buffer. These embodiments allow data collection to automatically adapt, e.g., by adjusting the sample rate to allow the data to fit in the limited buffer size. These embodiments can configure hardware and/or software on a valve positioner of a valve assembly to improve data collection for use in on-line valve diagnostics and other data processing techniques.