periodic counting

[Henok]

Hello!

This might be so easy to implement but not for me, at least not at the moment. I would like to create a CAD counter that I need to simulate for testing a subsystem I created, for demonstration purpose. The need is to be able to count from -360 to 360 with a resolution of 0.1 ( preferable if it can be adjusted as the need comes) periodically. i.e Once one full cycle is counted [-360,3609], then the count is supposed to start over.  

Has anyone implemented this before? I very much appreciate the help I get. 

As always thanks for all the helpful guys up here!

[GerdW]

Hi Henok,

sounds like you need a comparison function. Quotient&Remainder might help too...

Counting up to a limit and starting over again is a common task. Some pseudo code to get the idea:

ctr := ctr + 1
IF ctr >= upper_limit THEN ctr := lower_limit

[Henok]

Could you be more elaborate please? Like an example?

[Ranjeet_Singh]

2011 compatible vi please

[Henok]

Hi Ranjeet,

Here is the 2011 version of what I tried to do 🙂 

[GerdW]

Hi Henok,

try this:

It's just a simple math: use your loop count to calculate your scaled value...

[Ranjeet_Singh]

Hi Henok,

                                 I am attaching one VI. Enter 'resolution' &  'Delay between two count in ms' & run the program.

Try resolution as 1 & Delay between two  count in ms as 100 & see.

Hope this is what you are looking for. Let me know if you need any explanation.

Thanks

[Henok]

Thanks Ranjeet!

Its very impressive! I just could not know why it doesnt work for different resolution ( I tried 0.1 as it was my target). I tried to tweak the values and see if it works, but once it starts 360 with the current count, it kept counting up instead of starting over from -360. Any idea why?

[Ranjeet_Singh]

Please try this & let me know.

Kudos are always welcome.

[GerdW]

Hi Henok,

the problem arises from using the "equal?" comparison on floating pouint numbers.

Ranjeet forgot the inaccuracy of such numbers as was explained a lot of times before in the forum...

Conclusion: NEVER compare floating point numbers for equality!!!

That's the reason why I was using integers for the "counting" part in my example followed by a simple scaling to your desired range...