Solution
We can see information from
Auto Zero Once, with Auto Zero set to
Once, the offset error is measured when the acquisition task starts. The offset error measurement introduces a delay from start to the first sample clock. You can query the start delay with the DAQmx Trigger Property Node (
Start » More » Delay). The start delay is in units of 100 MHz timebase ticks by default. For example, Ticks/100MHz is time, so 101k ticks is 1.01ms. That's just the hardware impact, software also does more stuff when doing Auto Zero Once.
With Auto Zero set to
Every Sample, the offset error is measured at the beginning of every sample period.