contour plotting

[junyanyap]

I played around with my vi just now, and i realised that it is my trigger signal that is giving a problem..

I used a square waveform as my so called "trigger channel" for my driver vi. There is a red dot on the vi box.

Just now, i played around with different waveform generator, and accidentally unlink the "trigger channel" to my generated waveform, and "poof" my voltage reading and 3D contour has some readings.

Now I have to figure out how to use my generated square waveform to serve as my trigger. Any help?

[junyanyap]

hi hanrock,

my program is working already,

Thanks for the help.

I have 1 last qns on waveform plotting.

Everytime my nested loop runs, the graph will restart after 1 completed inner loop.

How do I make it continue plotting instead of restarting?

Thanks!

attached is the updated VI

[hanrock · Accepted solution]

Create one more shift register in the outer loop. Graph controls do not have buffer for history, while Chart controls do.

[junyanyap]

Dear Hanrock,

Thanks alot! It works:) Brilliant.

I have 1 last qns on my voltage reading. My driver doesnt have the function of reading the instantaneous voltage. The subvi of the driver only reads the amplitude, which i believe is the amplitude over a certain time. Is there anyway to use non-driver vi to extract the instantaneous voltage?

[hanrock]

It seems more like a mathematic problem. Search "differential" in the palette search, and you might get the related VIs.

[junyanyap]

I think i phrase my question wrongly.

What i meant is that i want to get the reading of the voltage at certain intervals. However, the driver only has one that reads the amplitude.

Is there any non-driver vi that i can use to read the voltage at fixed intervals that i set?

[hanrock]

Have a "Wait Until Next ms Multiple" node in your loop and wire the interval you want to have to this node. The unit is millisecond. Put your driver that reads the amplitude in the loop as well. If your VI is time critical, replace the loop with "Timed Structure".

[junyanyap]

Dear Hanrock,

I have placed the "wait until next ms multiple" into the loops. I have also included a stacked sequence, so to ensure that the inputs enter the loop at the same time.

In addition, i found out that my arrays input are faster than the voltage sweep, thus resulting in a faulty logging of data, and a wrongly plotted 3D contour. I corrected it by getting the input of the voltage sweep and inputting it into the array, rather that using the "i" of the loop and do some mathematical manipulation to get the value. It was my "stupid" mistake that causes the mismatched in timing etc. Sorry about the trouble. But your suggestions and methods are good, and assisted me in solving my problems.

Thanks alot!

Below is my updated vi

[junyanyap]

Hi all,

I noticed a tiny red dot on my array. May i know whats the problem with that? and i think that red dot is causing error in my 3d contour output.

Thanks.

[hanrock]

Implicit conversion. The termials you wire together do not have the same type but they are compatible with each other. The result is either data precision loss or additional memory copy. Or maybe both.