The sampling rate specifies the time intervals at which the FP Data Analyzer requests samples from the PLC, e.g. if the sampling rate = 10s, the FP Data Analyzer requests a new sample for each visible channel every 10 seconds. For additional information, please refer to Time format.
The Nyquist-Shannon sampling theorem states that the minimum sampling frequency must be at least twice the signal bandwidth to avoid loss of information. For instance, if your fastest signal changes every second, your sampling rate must be at last 500ms.