Control loop from task is not supported by PCI6229?

[eFang]

Hi, Chris_K,

I've been struggling with this problem. Fortunately I find some idea to build a measurement "row", but the chart shows nothing and everything else works OK. So I upload this VI file. Please help me to check how I should modify it.

Thanks a lot and have a nice weekend.

Yigang

[eFang]

Sorry, I missed one subVI. I'm uploading a complete package.

efang.03+.zip

[Chris_K_]

Hi eFang, from what I can tell from your attached VIs is that you are configuring a digital input task.  Have a look at the attached VI, it basically creates a analog input task, and reads the first three channels of your DAQ device.  I think this is what you are looking for.  You may need to play around with the timing so it suites your specific application, but I think it should put you on the right track

Chris_K

[eFang]

Hi, Thanks for your help.

I learned a lot these days from NI.com website. Yet I still have some problem with my program. When my program is running, I start your program, 3chAlread.vi, and I almost got nothing but a short line on the chart(screen shot attached).

Besides, I got some examples, synchronization_code.zip,  from http://zone.ni.com/devzone/cda/tut/p/id/4322. But I always got nothing on the chart while running the "Fig 2 - Multi-Function-Synch AI-AO.vi". No sine wave, no any waves.

Is something wrong with my hardware?

Thanks in advance for your time.

[Chris_K_]

Hello eFang.  I am glad that you are learning more about data acquisition and the DAQmx driver.

Before we conclude that there is something wrong with your card have a look at the following link and try to read a basic voltage in a test panel in Measurement and Automation Explorer (MAX).  I would suggest either trying to read a known voltage (a 1.5 or 9 volt battery works well).  You can also try a loopback test by connecting the analog output to your analog input and write a value or wave form to the analog output and attempt to read it with a analog input.  This can all be done from the test panel in MAX. 

If these tests indicate that your card is not working I would suggest calling our technical support for further troubleshooting, and we can have the card repaired.      

Chris_K

[ThijsBoeree]

Hi there i saw that you were a LabVIEW veteran and i have a question and posted already on this forum but still doesn't have the correct answer:

I wish to make a daq program, where i can get hardware timed daq (every 1 second 500 samples 8 channels, this for writing to a specific file format that needs 500 * 8 samples per block). And in the same program a smooth update (not with 1 update/second) of all the latest available data.

I first thought of a hardware timed loop but i can't get it to work with my USB6215 device, i get an error that my device doesn't support the requested operation (i try to use my daq counter as an external timing source for the timed loop).

I sincerely hope that you can help me...

Best regards,

Thijs Boeree

Message Edited by ThijsBoeree on 03-11-2008 09:56 AM

[Chris_K_]

This is a duplicate post. Please refer to this link for further information.

In order to maintain the forums in an orderly manner and to keep problem solutions and information in a consolidated fashion easily searchable by customers we ask that you post related questions in the original forum thread.

Best of luck in future applications.

[eFang]

Hi, Chris_K,

I tried as you said and it worked. I wired one an AO to an AI and then measured the signal I outputed. Now my goal is to display the signals simultaneously in one chart, illustrataed as the attached image. I did some research about chart and graph, and found out that chart is closer to what I want. But when I use chart in my vi, it always act anomaly.

My goal:

When the period and number of cycles are entered, the x axis scale should be readjusted to the whole running time, starting from 0 to the maximum without erasing.

Both AO and DO signals should be displayed in one chart, similar to the attahced image.

Questions:

1) How can I setup the chart to get the display on the front panal?

2) I wired AO 0 to AI 1 and P0.0 to P0.5 separately for measurement. Therefore I lost 1 AI and 1 AO. I guess there must be another better way to perform the measurement since the signals arise from my vi. Could you give me some tips about this?

I really appreciate your attention and your help.

Yigang

Attached are my VIs and the desired panal looking.

[Chris_K_]

Hello eFang. 

I am not sure exactly what you are looking for in a chart display type, but it you may find what you are looking for with respect to update type if you right click on the chart, select X scale and select AutoScale X.  This will auto adjust the chart so that all your data is displayed and non of it will be deleted.   If this is not what you are looking for can you please re-explain what you are looking for.   

In order to read in a voltage into LabVIEW you must use a analog input task, even if you are generating the analog output from the same VI.  If you want to display the digital information in the same graph at the analog data you can read in the digital output with an additional channel on you current analog input.  This way you can easily display both signals on the same graph.

Let me know if this helps.

Chris_K

[eFang]

Hello, Chris_K,

Thanks for your patience and time.

What I want in a chart display is exactly you can see in the attached picture: cell1.PNG, which I uploaded last time. I tried autoscale for x axis or customizing those scales but it didn't show like cell1.png shows.

If you can run my vi, could you do that to see what it looks like? I think this will make my question clearer.

Thanks again and have a great weekend.

Best,

Yigang