trying to use the TIMER to work out how many mS there are between triggers

[Hasham622x]

Hi all,

First of all, sorry for disturbing.  I tried to use the TIMER to work out how many mS there are between triggers, but I don't think I did it correctly so have a look and could you please guide me. I'm trying to read the TIMER when the trigger occurs and to save the value as "prev time". When the next trigger occurs, I read the TIMER and subtract the "Prev time" to see how long it took.

I set 10 Hz frequency trigger signal. 

I also attached old version LV19 code.

Kind regards

Hasham

[Jay14159265]

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@Hasham622x wrote:

Hi all,

First of all, sorry for disturbing.  I tried to use the TIMER to work out how many mS there are between triggers, but I don't think I did it correctly so have a look and could you please guide me. I'm trying to read the TIMER when the trigger occurs and to save the value as "prev time". When the next trigger occurs, I read the TIMER and subtract the "Prev time" to see how long it took.

I set 10 Hz frequency trigger signal. 

I also attached old version LV19 code.

Kind regards

Hasham

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try using a shift register and the 'first call' Boolean instead of local variables, like this: 

 

 

 

 

[altenbach]

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@Jay14159265 wrote:
try using a shift register and the 'first call' Boolean instead of local variables, like this:  

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... and if you would use a globally initialized feedback node instead , you could eliminate the "first call" complication. 😄

[Jay14159265]

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@altenbach wrote:

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@Jay14159265 wrote:
try using a shift register and the 'first call' Boolean instead of local variables, like this:  

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... and if you would use a globally initialized feedback node instead , you could eliminate the "first call" complication. 😄

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 Hello @altenbach, well this was the best I could come up with for that. When I learned LabVIEW, I was taught to not use three things; Local variables, waits, and feedback nodes. Are feedback nodes really that bad? Maybe that was just the code style at that firm. 

 

[mcduff]

The first iteration will be off, but simple after that. Can just stick in the while loop. Can move t0 outside the loop if the first point is important.

[altenbach]

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@mcduff wrote:

The first iteration will be off, but simple after that. Can just stick in the while loop. Can move t0 outside the loop if the first point is important.

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The first point will be zero (not "off", whatever that means 😄 ), because no iteration has happened yet.

[mcduff]

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@altenbach wrote:

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@mcduff wrote:

The first iteration will be off, but simple after that. Can just stick in the while loop. Can move t0 outside the loop if the first point is important.

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The first point will be zero (not "off", whatever that means 😄 ), because no iteration has happened yet.

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Off as in "Off the mark", not LED on/off. 🙂

From the dictionary

not accurate or correct : not achieving the desired result. Their estimates were completely off the mark.

[Jay14159265]

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@mcduff wrote:

The first iteration will be off, but simple after that. Can just stick in the while loop. Can move t0 outside the loop if the first point is important.

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Nice, so is the preferred over the shift register or just less clicks to get the same code functionality. 

[mcduff]

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@Jay14159265 wrote:

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@mcduff wrote:

The first iteration will be off, but simple after that. Can just stick in the while loop. Can move t0 outside the loop if the first point is important.

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Nice, so is the preferred over the shift register or just less clicks to get the same code functionality. 

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I think it is up to your preference, sometimes a shift register is easier, sometimes a feedback node is. The advantage of the feedback node in this case, is that the code can now fit on a "postage stamp". For some, that is preferable. 😉 

[Hasham622x]

First of all, thanks for your reply. I tried this shift register option, and it gives some random numbers, not actual time ...

Kind regards

Hasham