Integrator control with timed loop

[laskar01]

Hi all, when dealing with discrete time control like the poleplacement method, the sampletime shouldn't necessarily be

as short as possible like in "analog" PID-control.

I want to be able to set the time of how often I am sensing the input and therefore I am using a timed loop.

Something is missing in my file because it won't work.

The propertynode DigNum is not inserted by me, but by the png-software. I have a local variable there refering to the period dt.

Kindest regards,

Lasse

[GerdW]

Hi Lasse,

"Something is missing in my file because it won't work."

Yes, the error description is missing. What is wrong? What exactly doesn't work?

- Instead of using locals you could use a wire or the block in the upper left of the TimedWhileLoop to get dt from it...

- Does the loop spin as fast as you want it to spin or do the ExpressVIs slow down the execution?

[laskar01]

Oh sorry for that.

Nothing happens.

[GerdW]

Hi Lasse,

as the waveform graphs are empty it seems you don't get any data from your DAQassi!

You're using the channel "Voltage" in your DAQAssi1 - and we aren't able to check your settings...

[laskar01]

Hi all, and thanks for your patience GerdW.

I am using "1 Sample (HW-timed)"

The reason is that I've seen controltutorials where they use a while-loop with "1 sample (SW-timed)" to get a variable dcvoltage, when no control over the time is needed.

Since I am using a timed loop, I supposed that I can use "1 Sample (HW-timed)".

regards,

Lasse

[GerdW]

Hi Lasse,

"Since I am using a timed loop, I supposed that I can use "1 Sample (HW-timed)"."

Why do you think so? You still use software timing, it's just a slightly different loop construct...

When using "HW-Timed" access you have to define the sample rate before starting the task!