Graph refreshing speed??

[RileyC]

Gday guys.

Iam very new to labview. I am currently using labview to read/record/show data from an LVDT.

I have got the program to run for a user defined period of time. Ive also got a button that zero's the graph's history if another test needs to be under taken. Ive attached that VI (MK3MOD0). I am happy with the 500ms rate that data is shown on the XY graph.

 
Ive been looking through this forums and being trying to use some of the code and examples that other people have posted for zeroing a channel. I need to be able to set up my LVDT in a semi displaced mode so i can measure displacement in both a positive and negitive direction.

But this is where ive ran into some problems. The VI i created is (MK3MOD1) this allows a zeroing of the input but for some reason which i cant understand seems to refresh/display graph data at much longer intervals than my first version. Am i missing something really simple?

Thankyou
Riley

[altenbach]

In the second example, you read 10x more samples (1k vs 100) at 1kHz, thus each iteration takes 10x longer.

[altenbach]

Overall, you code is extremely convoluted and makes very little sense. Can you explain exacly how it should work, how the user should operate it, and what you are expecting on the graph.

One-shot programs (without an outer while loop and at least some simple state machine architecture are very incomplete. That "reset to defaults" in the first program makes no sesne at all, because it executes once concurrently with the start of the loops and reamins inoperaeble for the rest of the run. Your use of an event structure is also misguided, because you are polling anyway. A simple case structure would be sufficient.

[RileyC]

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@altenbach wrote:

Overall, you code is extremely convoluted and makes very little sense. Can you explain exacly how it should work, how the user should operate it, and what you are expecting on the graph.

One-shot programs (without an outer while loop and at least some simple state machine architecture are very incomplete. That "reset to defaults" in the first program makes no sesne at all, because it executes once concurrently with the start of the loops and reamins inoperaeble for the rest of the run. Your use of an event structure is also misguided, because you are polling anyway. A simple case structure would be sufficient.

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Thankyou for the response.

Have to agree though with what you said about my programming.

All i was given at the start of this project (never heard of labview before this point) was the labview for engineers manual and have been pretty much on my own from then. So ive been relying heavily on this forum to do examples/ try and figure out what i need to do my test as i have very little background in programming.

Ideally this software is to be used by others when conducting an Oedometer test (measuring the consolidation of a clay/silt sample under loading over a 24hr period(48hr for extreme cases)). Due to the standards here requiring relitivley frequent tests there is a big manpower/time outlay for one of these tests at my uni.

-The graph should show the displacement of the LVDT. I would like the graph to show the whole history of the test.

-The reset to defaults button is so that the graph can be cleared and run again if it was setup incorrectly etc (is there a better way doing this?)

-The graph needs to be able to be 'zeroed' so it can show movement of the LVDT in both directions.


Hope that helps explain things

Thanks again
Riley