topic Re: Indicator for a waveform array? in LabVIEW

Indicator for a waveform array?

glskinner — Mon, 07 Jan 2013 14:20:55 GMT

I'm looking to put indicators for 4 waveforms graphs I have in an array. I have tried using the index array and have even tried wiring an indicator straight to the data wire of my source. When I do both, the update for the indicator seems to be intermittent. It's not updating properly. I have a time elapsed VI with a case structure that should update it every .3 seconds, so I can read the damn thing. Any suggestions?

Re: Indicator for a waveform array?

vt92 — Mon, 07 Jan 2013 19:02:34 GMT

I've looked at your code, but I can't understand what you are trying to do. I see the graphs. What do mean by indicators? Did you want to display the data into an array?

Re: Indicator for a waveform array?

glskinner — Mon, 07 Jan 2013 19:15:50 GMT

I want to display the voltages for each channel on the indicator, so I know what voltage I'm starting my test at.

Re: Indicator for a waveform array?

glskinner — Mon, 07 Jan 2013 20:37:49 GMT

How do I get the realtime voltage value from each channel, being that they're all in an array?

Re: Indicator for a waveform array?

vt92 — Mon, 07 Jan 2013 20:42:38 GMT

So, you want to see the last value measured from each channel? Just get the array size and index to the last element.

Re: Indicator for a waveform array?

glskinner — Mon, 07 Jan 2013 20:52:42 GMT

do I do this before or after I index each channel in a waveform array?

Re: Indicator for a waveform array?

glskinner — Mon, 07 Jan 2013 21:20:07 GMT

That was the wrong question. I'm not completely sure how to use the size function. I'm not familar with arrays,

Re: Indicator for a waveform array?

glskinner — Mon, 07 Jan 2013 21:25:46 GMT

This is the last leg of my VI. It seems like a simple issue, but it's dealing with arrays, so I'm in a bind over it!

Re: Indicator for a waveform array?

vt92 — Mon, 07 Jan 2013 21:51:29 GMT

Index the waveform and then get the last element.

Re: Indicator for a waveform array?

glskinner — Mon, 07 Jan 2013 21:54:26 GMT

why doesn't the indicator update at a regular interval?

Re: Indicator for a waveform array?

vt92 — Mon, 07 Jan 2013 21:59:24 GMT

Your loop time will be 0.3 seconds plus the time to run the other code (ULx Read, etc)

You don't have the timeout wired to ULx read, so you don't know how long that subvi is running.

From the ULx read help:

timeout specifies the amount of time in seconds to wait for samples to become available. If the time elapses, the VI returns an error and any samples read before the timeout elapsed. The default timeout is 10 seconds. If you set timeout to –1, the VI waits indefinitely. If you set timeout to 0, the VI tries once to read the requested samples and returns an error if it is unable to.

Re: Indicator for a waveform array?

glskinner — Mon, 07 Jan 2013 22:56:58 GMT

So what exactly do I have to do for the indicator to show realtime values?

Re: Indicator for a waveform array?

RavensFan — Mon, 07 Jan 2013 23:11:09 GMT

Show your latest updated code so we can see how you've incorporated it the changes.

Re: Indicator for a waveform array?

glskinner — Mon, 07 Jan 2013 23:16:31 GMT

here ya go,

Re: Indicator for a waveform array?

vt92 — Tue, 08 Jan 2013 13:43:26 GMT

How fast will they update if you remove the elapsed timer?

Re: Indicator for a waveform array?

glskinner — Tue, 08 Jan 2013 13:59:47 GMT

I tried that, there's so set time. Like I said before, the indicator values update intermittently, even when I remove the elapsed timer.

Re: Indicator for a waveform array?

RavensFan — Tue, 08 Jan 2013 14:24:10 GMT

How often is "Intermittently"? If you remove the elapsed timer, then something else in the loop is controlling the update rate and the iteration speed of the entire loop. It could be the acquisition settings you are using for the DAQ device.

Re: Indicator for a waveform array?

glskinner — Tue, 08 Jan 2013 14:47:10 GMT

It seems to come through the indicator every 11 seconds or so. I'm using 25000 samples per channel, continuous samples, with onboard clock, as seen in the VI.

Re: Indicator for a waveform array?

glskinner — Tue, 08 Jan 2013 14:49:09 GMT

I'm using a MCC usb-1608fs

Re: Indicator for a waveform array?

vt92 — Tue, 08 Jan 2013 15:46:53 GMT

Here's a cleaned up version without the file save option. Run it and see if it is faster/better.

I don't understand your logic, so I'm not making any guarantees that the codes runs correctly.