[FGEN] How to start a triangle wave from 0V?

[Basjong53]

I have a PXIe 5413 function generator. I want to use it to send a triangle wave between 0 and 1 V, starting from 0V. This simple using a standard waveform, but enabling the FGEN output briefly sets the output to 0.5V. This should not happen as it affects the measurement. Here is what the oscilloscope measures:

And here is my code:

The voltage also goes to 0.5V shortly after I stop the generation. Which is even weirder, because I disable the output before aborting the generation...

I have tried to add a DC waveform with DC offset of 0V before starting the triangle wave, but then it gets even worse:

How can I fix this?

[altenbach]

---

@Basjong53 wrote:

And here is my code:

---

No, that's just a picture. LabVIEW code has a *.vi file extension.

Sorry, I am not familiar with your instrument, but have you tried to set the start phase to something different than 270 degrees?

[santo_13]

I guess the issue is that the offset you configure 'adds' electrical offset in the front-end of the device and hence puts the output at 0.5V before it starts the actual triangular wave generation.

You may have to use ARB mode instead of standard function generation. This way, you maintain the offset at 0V and start at any phase of the wave.

[Basjong53]

---

@santo_13 wrote:

I guess the issue is that the offset you configure 'adds' electrical offset in the front-end of the device and hence puts the output at 0.5V before it starts the actual triangular wave generation.

You may have to use ARB mode instead of standard function generation. This way, you maintain the offset at 0V and start at any phase of the wave.

---

I have just tried the arbitrary waveform and it has the same problem .

For some reason, it also outputs double the frequency that I set... ("Use waveform dT for Sample Rate" doesn't change that)

Any other ideas?