CF-3000 Frequently Asked Questions

Data analysis can be done without any issues.
The number of data points (lines) that can be collected becomes the problem.
Since the FFT calculation speed of the CF-3000 is about 40ms, it can collect 25 data points per second. If the rise time of the object being measured is 30 seconds, then 30 seconds × 25 = 750 data points can be collected, which is sufficient to reach the upper limit of 400 lines for tracking.

<Note>
What needs to be noted in tracking measurement is during low rotation. At low rotation, the sampling clock slows down, causing a degree shift (due to the longer data capture time ratio against rotation fluctuations, the degree peak moves within one frame). It is ideal to slowly increase the rotation during low rotation. Depending on the engine, subtle rotation control may not be possible, so it is better to display the power spectrum waveform at low rotation and check if there is any degree shift.

<1>Rotation increase and computation time
When converted to 1P/R
0–35000rpm = 0–583Hz (increase)
The change rate per line is
583÷400=1.46Hz (=0.6s)
Since the computation time is 40ms, there is no problem with the FFT computation time.

<2>Sampling time
The sample time at 1200r/min in the 25th range
is 2048 points ÷ (1200r/min ÷ 60 × 1p/r × 64 multiplier) = 1.6s
and the sampling time is a concern. (It is prone to order deviation)

(1) Slowly increase at low rotation
(2) Set the degree setting to a larger value.
(3) Reduce the number of sample points to a small value like 1024.

Measures are necessary, etc.