The First Sample Timestamp attribute/property can only be enabled for hardware timed tasks, and is enabled by default for Analog Input and Digital Input tasks. For Digital Input tasks as well as C Series Slow Sample and Delta-Sigma Devices, the first sample timestamp will be the t0 for waveform reads. For C Series Scanned Devices, the t0 for waveform reads will be the first sample timestamp plus an additional delay to more accurately reflect the time at which the sample was taken.