Generating PWM Signal

[Emna20]

Hi,

i have three tanks . the first contains O2 ( oxygen ) the second one contains Air . in a specific period of time (T) i need to full the third tank with ( 25% of oxygen + 75% of Air ) . i Don't have any sensor to mesure the percentage of O2 and Air . i want to use the PWM signal .

can anyone help me.

Best Regard.

[GerdW · Accepted solution]

Hi Emna,

---

@Emna20 wrote:

i Don't have any sensor to mesure the percentage of O2 and Air . i want to use the PWM signal

Can anyone help me.

---

Help with which problem?

Is there any problem?

What have you tried? Where are you stuck?

Which hardware do you use?

[Emna20]

Hi,

sorry,

I have two valve in (O2) tank and in ( Air ) tank (digital valve : true to open the valve and false to close the valve) . I am going to use the NI CRIO-9068.

Output / Input Module NI 9401.

I want to generate a PWM signal to command the valves. for example i want to full the third tank in specific period T with (20% Oxygen and 75 % AIR ) i have no idea in generating PWM Signal , i Don't Know where to start  . these is my first time i want your help .

Thank you

[GerdW]

Hi Emna,

---

@Emna20 wrote:

Output / Input Module NI 9401.

i have no idea in generating PWM Signal , i Don't Know where to start  . these is my first time i want your help .

---

This is not your "first time": you're a member of this forum since January with >100 posts.

You had more than 2 month to take LabVIEW training and read manuals…

The cRIO and it's modules install a lot of example VIs in the example finder, take them to learn about their usage!

---

@Emna20 wrote:

I want to generate a PWM signal to command the valves. for example i want to full the third tank in specific period T with (20% Oxygen and 75 % AIR ) i have no idea in generating PWM Signal

---

How does such a PWM signal help with setting a certain mixture of different gases?

[PatrickMiller]

I think that they're trying to have one of the valves pulse at some frequency/duty cycle %open vs % closed and have the air tank be open 3 times longer than the oxygen tank with the "intent" that the tank being filled would be 1/4 oxygen and 3/4 air.  

[BertMcMahan]

Granted I'm not in the chemical field, but I've never seen a standard air valve that would work with a PWM input. Is it some sort of proportional valve that takes a PWM input as its control signal?