Time trase measurement and some zero data

[rviktor85]

Hello,

We are using the PicoHarp330 device and snAPI to start and run time trace measurements, but what we noticed is that if we run a measurement for 10s, we don't get 10s of data, as at the beginning we have a part of zero (empty, I guess) data. Hence, 10s of data consist of zero part + the real measurement part.

We created a small code snippet that demonstrates this issue.

def small_test(
        self,
        tag,
        num_bins,
        history_size,
        acq_time,
        wait_time,
):
    self._device_handler.timeTrace.setNumBins(int(num_bins))
    self._device_handler.timeTrace.setHistorySize(history_size)
    self._device_handler.timeTrace.measure(acqTime=int(acq_time), waitFinished=False, savePTU=False)
    time.sleep(wait_time)

    start_time = time.time()
    while not self._device_handler.timeTrace.isFinished():
        self._device_handler.timeTrace.stopMeasure()
        time.sleep(0.01)
        if time.time() - start_time > 5:
            self.logger.error("The device stopping timeout")
            break

    counts, times = self._device_handler.timeTrace.getData()
    counts = [np.asarray(c, dtype=float) for c in counts]
    t = np.asarray(times, dtype=float)

    if len(t) >= 2:
        dt = history_size/num_bins
        t = np.arange(len(t)) * dt

    plot_timetrace_measurement_data(t.tolist(), counts[1], tag=tag)

If we run it with the following argument values: small_test(tag="small test", num_bins=1e4, history_size=10, acq_time=10e3, wait_time=10 ), we obtain the attached plot image. We have the same results with acq_time = 0, also with the variants where we put waitFinished=True in the measure function..

Is there something that we are doing wrong? The goal that we are trying to achieve is that if we let the measurement run for 10s to obtain 10s of data. We tested with different settings, but the only change is the amount of zero data.

Thank you for any help/suggestions.