infinitenothing

If the red dot is scary, you can just drop in a "to fixed point" in there. It explains the conversion (rounding mode and overflow mode) a bit better. In this case, the output is exactly the same as the input in the same way that 16 is the same as 16.0.

I don't have a canned solution for velocity profiles. I'm sure there's something nice out there. It might be possible (though, probably there's quite a bit of effort involved) to roll your own controller. You could use a 9401 to output a PWM signal to something like an H-bridge, if you're micro-stepping, you'll have to use another module, maybe a 9221, to measure the current out to the motor, etc.

What sort of interface are you looking for? RS232? What controller are you using? PC? CRIO? Soft motion rather fancy—what sort of features do you need? Just regular acceleration, velocity profiles? Encoders?

Just scale it

If you don't want to use a feedback node, another option is using a local variable (see example below)

It sounds like you're trying to process losslessly. If that's the case, you usually need some sort of buffer. In this example, I use the event queue as my buffer.

Initialization behavior is well defined in the settings of the feedback node.

https://zone.ni.com/reference/en-XX/help/371361L-01/lvconcepts/block_diagram_feedback/

I'm not sure what you mean by force. Are you trying to make it into a d latch?

To clarify the previous post, the two loops can share a wire as long as that wire is an input to both of them. If the wire is an input from one and an output to the other then the loop that is expecting the input will have to wait for the other loop to output the data.

If you intended to use that wire to communicate data between the two loops, maybe convert the wire between them to a channel wire?

I'm not too familiar with the FIFOs so I can't answer those questions but I noticed your error handling is a little weak and doesn't capture errors while you're inside the loop.

Usually you want to run your timed loop at your control rate (some target rate you choose). It's a little less common to try and run it losslessly as you might trying to do. If you wanted to run losslessly, you could maybe set the loop time to 0 or maybe create a timing source from your task:

http://zone.ni.com/reference/en-XX/help/371361R-01/glang/create_timing_source/

16 hours ago, SteveSun said:

I want to implement a function as follows: first set the Max and Min voltage values, then set the number of steps in the middle of the Max and Min steps and the dwell time of each step, and finally set the total number of cycles
The problem is: the value of each step must be output separately, there is a problem here, please help, thank you!

I think you need to replace your rotate array with another for loop with your wait inside. The inner for loop will autoindex your array and output the values one by one. If you post a VI or a snippet, we might be able to better show you what we mean.

The outer one can't turn true while you're inside of the inner one. It's just like a nested if statement in C.

It should still work in RT even if it doesn't show up on the pallets. Try it. Or, check out the underlying code and copy that.

Basics lesson 1 has that VI in the lower right quadrant. You can also search for the VI by name using quick drop

Also, on the help page it tells you the owning palette (Timing VIs and Functions) so you can find that VI.

I recommend you change your booleans on the main panel to Latch When Released

I modified your bool test subVI so it would pop up and stay active until the user closed the panel

It would really be nice to see some code or even like just the concept to see what you're talking about. Have you seen this VI?

http://zone.ni.com/reference/en-XX/help/371361P-01/glang/stall_data_flow/

You can tell the graph that your waveform is offset by using bundle cluster

4 hours ago, ShaunR said:

Are there plans to fix all the bugs?

I've just spent a month writing two xcontrols and all that was mainly finding workarounds to the bugs (and I still don't know why some of the work-arounds actually work)

I doubt there are plans to fix any of the bugs. Some of them have been going pretty much since the start.

Are you setting verify to "false"? The verify server input is for using client certificates. I don't think you need it if you are connecting to a public site. I believe in that case, the function will verify with public CAs instead of using your client cert.

Recert by points always seemed like too much accounting effort. I'd do it if there was a website where you could submit the request and have it keep track of everything.

Yes, what you're doing is super common. It might be worthwhile to use the TDMS file format instead of a spreadsheet file. It's a very easy format for recording and playing back data.

I'm a little curious why you're using a CRIO. It's not a bad choice but something a CDAQ could be simpler.

5 hours ago, ShaunR said:

I know you are looking for the most precise method for this type of waveform, but is there a reason you can't do a peak detect to remove the lead-in?  

At this point, AutoCorr is working well enough and I'm just curious about the advantages and disadvantages of different methods. My signals are rather noisy so it's not always super clear how far back the "start" is from the trigger.

Thank you for the tip. The performance seems similar to ZoomFFT.

On 2/9/2019 at 7:45 AM, Francois Normandin said:

If you need to track frequency in a noisy realtime environment, I've seen Kalman-based filtering being used. 
Unfortunately, I don't have an implementation example to provide. NI has this discrete filter in the Control Design and Simulation toolkit... which does not come cheap.

Interesting. I've seen its use in things like GPS. Actually, in my particular application, I'm not tracking a frequency. There's some "dead air" which I simulated above with the zeros and then the signal which is unrelated to the previous signal. Does that rule out Kalman or am I misunderstanding how you'd use it. I have the platform suite so I think I have the control design toolkit.

On 2/9/2019 at 9:05 AM, ShaunR said:

Wavelet?

Mhmm..yeah... I know some of these words. 😉 I'll take a look at some of the algorithms they mention.

I tried a few different ways of estimating frequency and I thought I'd compare them. If anyone has some other ideas or links to other techniques, I'd like to see how they perform.

Techniques used the VI:

• Zoom FFT
• PSD
• AutoCorrelation

Frequency Estimation.vi

You have a few options.

• Use a radio control if the booleans are mutually exclusive
• Combine the booleans into an array and then convert that to a number
• Nest your case structures

Maybe I should have tested this before I posted but if I switch Enque Serial Number to a .vim, the broken wire resolves and everything works out. Neat! I wonder if there are any unintended consequences.