LabVIEW
sine pattern and sine wave VI
The amplitude input is without units. For example, if you specify 3, then the sine wave values will be from -3 to 3. If you want mm, there must be some kind of conversion. When you say mm, how does this relate to the sine wave? Are you generating a sine wave voltage signal that drives a motor or other actuator that moves a device by a number of mm? Of so what is the relationship between voltage and the mm displacement generated by your actuator?
Sine Pattern has an input for number of cycles instead of frequency. So you need to figure out how many samples you want in your waveform and how many cycles this should represent. All this depends on the update rate you use for outputing your waveform to the actuator.
For example, if you want to update your
output at 1 kHz, choose to have a 100 sample waveform, and want a 20 Hz sine wave -> 100 samples will represent 0.1 seconds of data (at 1 kHz). So 0.1 seconds of a 20 Hz sine signal will include 2 cycles, so you should specify 2 cycles and 100 sample on the Sine Pattern VI inputs.
The Sine Wave VI frequency input is a bit more complicated as it is a normalized frequency input. Basically, figure out how many cycles you want. Then divide the # of cycles by the number of samples in the waveform you are generating and that is the normalized frequency you should specify. In our previous example, take 2 (# of cycles) and divide by 100 (samples in the waveform we generate). This gives you a normalized frequency of 0.02. This is the input for f (normalized frequency) on Sine Wave VI.
Christian L
Sine Pattern has an input for number of cycles instead of frequency. So you need to figure out how many samples you want in your waveform and how many cycles this should represent. All this depends on the update rate you use for outputing your waveform to the actuator.
For example, if you want to update your
output at 1 kHz, choose to have a 100 sample waveform, and want a 20 Hz sine wave -> 100 samples will represent 0.1 seconds of data (at 1 kHz). So 0.1 seconds of a 20 Hz sine signal will include 2 cycles, so you should specify 2 cycles and 100 sample on the Sine Pattern VI inputs.
The Sine Wave VI frequency input is a bit more complicated as it is a normalized frequency input. Basically, figure out how many cycles you want. Then divide the # of cycles by the number of samples in the waveform you are generating and that is the normalized frequency you should specify. In our previous example, take 2 (# of cycles) and divide by 100 (samples in the waveform we generate). This gives you a normalized frequency of 0.02. This is the input for f (normalized frequency) on Sine Wave VI.
Christian L
