knob control

[Phobi4]

Hi guys,

I have been doing some tutorials and some experimentation but I really can´t get there.

I was wondering if it is even possible to control the Amplitude and Frequency scale of the graph using two knobs on the attached VI.

Thanks. 

[MikeS81]

Hi Phobi4,

i don't have your HW vi's but you should open/close the connection to your HW only ones before/after the loop.

Mike

[Phobi4]

Sorry but I did not understand what you meant. Could you elaborate more?

Use noob talk if needed please. lol

Thanks.

[MikeS81]

Hi Phobi4,

from the vi names it should look like this.

Mike

[Gak]

Hi phobi4,

You can use property "X scale.Maximum" of graph to change scale of X axis at run time.You can also use property node to change scale of  y axis.

Also you can change increment , decrement etc  parameters using property node.see attached vi

Best luck

[Phobi4]

For MikeS81

What are the advantages of the while loop you mentioned instead of the whole thing with the while loop?

For gak

Thank you very much. That is exactly what I needed. Now I´ll try to implement it with the rest of the VI.

[Phobia]

Hi again,

So I tried to add a XY graph with no luck, giving me the following error when trying to connect the signal with the graph:

"You have connected two terminals of different types. The type of source is cluster of three elements. The type of sink is 1-D array of cluster of two elements."

I still have some difficulties on figuring out what types of data there are and which ones are connectable. Even when I try to use some functions with signal manipulation, I often get this kind of different data errors and do not know how to make them compatible.

Anyway, I used the graph I had and created two nods for the X a Y scale maximum. I can now control the Amplitude and frequency, but not the way I wanted. By changing the maximum values, I cannot get a centered graph like on a real oscilloscope. So I thought, if I establish a positive maximum value and a negative minimum value on the graph, I could use a knob to control both Yscale maximum and Yscale minimum, making the graph always centered. In my head it looked a good idea, but it did not work.

So I was wondering if you could help me on 3 things:

1-What can you say or recommend me to do, for a better understanding on the different types of data and connections on labview, so I can use various available functions without getting "different data errors";

2-How can I bypass this knob situation, so I can have a variation of both minimum and maximum values with one knob, making the graph always centered;

3-Which function is the best to mimic the oscilloscope trigger function, since there are more than 10 different types of triggering functions in labview. 

Sorry for this kind of testament. Thanks in advance.

P.S.->My hardware is a tektronix tds3034b and I use tktds3k revision 2.1 drivers for labview 8.0 or above. I also send attached content that could help.

P.S.2 ->I lost the login details for my other account (e-mail and password), so I am using this one now.

[Phobia]

Anyone?

[Dennis_Knutson]

1. Start with the tutorials. Then there are classes and books that you can use.

2. Your program design is faulty. First, you have the graph set for autoscale of both x and y axis and you do not want to be constantly writing to the property node. This should be placed in an event structure.

3. There is hardware that you can tirgger in different manners but I don't think it is correct at all to say that LabVIEW has any sort of trigger functions. Explain what you mean.

[Phobia]

---

Dennis Knutson wrote:

1. Start with the tutorials. Then there are classes and books that you can use.

---

 I have done some tutorials already, but still have some difficulty understanding the data types. Anyway, I am going to explore it even more.

---

Dennis Knutson wrote:

2. Your program design is faulty. First, you have the graph set for autoscale of both x and y axis and you do not want to be constantly writing to the property node. This should be placed in an event structure.

---

I don´t understand what you mean by that, since I always use autoscale off, otherwise the knobs wont work. Is there some kind of hidden autoscale option I missed? In the second part, you mean removing only the X and Y Scale maximum from the loop and insert it on an event structure?

---

Dennis Knutson wrote:
3. There is hardware that you can tirgger in different manners but I don't think it is correct at all to say that LabVIEW has any sort of trigger functions. Explain what you mean.

---

Normaly if you have some kind of unconstant waveform, you just press the trigger button on the oscilloscope and you get a perfect (kind of paused) signal. Just wanted to know which function replicates this more correctly, since my hardware drivers has a lot of them. For example:

Configure trigger, configure edge trigger source, configure trigger modifier, configure runt trigger source, configure glitch trigger source, configure slew rate trigger source, etc, etc, etc...

Thanks again for your time.