speed measurement using NI9401

[Lennard.C]

Hi Mass0873,

It's hard to understand when you give an explaination on what those attached screenshots are. May i ask what is your DAQmx version?

Error -201003

1. When you are doing the frequency measurement, you got the error -201003?  
2. When the error -201003 occured, did you check if:
   - The device (NI 9401) is present? Did you change the NI 9401 module to another slot when running that program? I noticed that from your screenshot 6 you have changed the NI 9401 at either slots 5 and 6 plus you have communicated with many cDAQ 9172.
   - Can you build a DAQ Assistant from scratch? When you do that, just measure directly from the DAQ Assistant and see if you get anything.
   - If not, have you tried testing it again using test panels for your NI 9401 and see if it is still functioning?
   - Else change it to another slot. Please do make the changes at the DAQ Assistant as well. Always counter check if the NI 9401 address is the same as shown in NI MAX. 

Error -200141

1. Based on the 5.jpg, you are measuring digital values from the NI 9401? And you have an error 200141 after that?
2. Can you provide the screenshot for the error 200141?

May I ask what do you mean you got a constant output voltage from the sensor? Is this happens when you are measuring frequency or digital values from the NI 9401?

You can look into examples on measuring frequency in NI Example Finder (Open LabVIEW >> Help >> Find Examples...). In NI Example Finder you'll need to limit your search to the hardware.  Under the search tab in NI Example Finder, select the drop down box for the "Hardware" (found on the lower left corner of the NI Example Finder) >> Select "Add Device" >> look for NI 9401 >> Drop it under the column "Device to find examples for" and click ok >> select the check box "Limit results to hardware" in NI Example Finder and enter keyword "Frequency". This should limit the search for any examples related to Frequency and your hardware.

Additionally, have you looked into these links?:

https://www.ni.com/en/shop/data-acquisition/measurement-fundamentals/frequency-measurements-how-to-g...

https://forums.ni.com/t5/Multifunction-DAQ/TTL-NI-9401-Edge-counting-work-but-not-frequency-measurem...

https://forums.ni.com/t5/Counter-Timer/NI-9401-pulse-width-measurement/td-p/1099235

Warmest regards,

Lennard.C

[Mass0873]

Thanks for reply.
Sir,our DAQmax version is 4.6 of 1.Today we are getting 200022 error now.We tried with other sensors also,nothing is displayed on Labview except error.Shall we change the pin connection? currently we are giving external supply to sensor and the output is conncected to pin 16 of NI 9401.Have you gone through our .vi program.Where is problem?

Thanks

[Lennard.C]

Mass0873,

1. First of all, you have not given me any VIs but just screenshots and your screenshots seemed to be okay from what I can see.
2. Second, are you certain that you are using DAQmx 4.6.1 or NI MAX 4.6.1? 
3. Can you provide screenshot of the error 200022?
4. What have you done to get that error (provide screenshots and VI)?
5. What is the external supply voltage value? 
6. Did you connect it to the common ground as mentioned in the page 10 of the NI 9401 manual? https://www.ni.com/docs/en-US/bundle/ni-9401-getting-started/page/overview.html
7. Check using a probe if your sensors are giving the right readings. 

The following link: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P7gKSAS&l=en-US, mentions that the device is being reserved for another task. Did you add 2 DAQ Assistant?

Regards,

Lennard.C

[Lennard.C]

Hi Mass0873,

Here's some additional info. Have you looked into these?: 

https://www.ni.com/docs/en-US/bundle/ni-daqmx/page/digiocseries.html

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019MFFSA2&l=en-US

https://forums.ni.com/t5/Example-Code/CDAQ-9178-Count-Digital-Events-Without-Digital-Module/ta-p/352...

Warmest regards,

Lennard.C

[Mass0873]

regarding the test panel, we do get pulses on test panel.but we are not getting any waveforms or particuar result in the front panel.Attached are the screenshots.

[Lennard.C]

Hi Mass0873,

May I ask what you have done which you are able to detect the pulse from the test panels?

Have you tried the VI found in the example here: https://forums.ni.com/t5/Example-Code/CDAQ-9178-Count-Digital-Events-Without-Digital-Module/ta-p/352... which I mentioned in my previous email?

You'll need to change the channel name in the code. 

If it does not work, I suggest that you should contact your local NI rep.

Warmest regards,

Lennard.C

[Mass0873]

Hi Sir,

Thanks for replies.Our DAQmax version is 8.9.5f5 and NIDAQ version is 7.4.4f7

The current status of our experiment is we are getting some data from DAQ,but we are unable to interpret which value is speed from these values.I have attached the image that shows DAQ assistance measured value.Also when we run the program without intermediate arithmetic operator, we are getting a weirdo graph from that measured values.But if we try to run program with that operator, no output in front panel,blank waveform graph.Please have a look on both .vi 

Whats wrong are we doing?What kind of the graph should we get?How to get speed as values keep on changing with time?

Sorry for troubling you.

Thanks

Amar

[johnsold]

I still suspect that the comments I made much earlier in this thread are at the root of your problem. The signal from your sensor is NOT a good logic-level signal. The result is that the counter gets extra counts on some transitions. Put a 74HC14 or some similar Schmitt trigger logic device between your sensor and the counter to clean up the sensor signal.

Lynn

[Lennard.C]

Hi Mass0873,

Have you tried what johnsold have suggested? It could be that the signal from your sensor is NOT a good logic-level signal. The result is that the counter gets extra counts on some transitions.

Give it a try and see how it goes.

Warmest regards,

Lennard.C

[Mass0873]

Hi sir,
I have tried to get reading with large value divisor (20000~25000).I was in two counters large value mode.There were no much fluctuation in readings.
But how can i manipulate to get desired reading of speed.
What should be waveform graph nature for speed calculation?how it should be a straight line or rise and fall around a some constant value which a rotating speed of my dc motor?

Thanks
Amar