Display rpm by acquiring digital TTL signal using NI 9401 counter

[cwilcox]

OK, I was able to get the large range counter to work by myself, however I still don't understand why the low frequency counter doesn't work. If anyone has any ideas they are welcome.

Thanks,

Chris

[aNIta B]

Chris,  I attached that vi after saving back to 8.0.  What do you mean when you say it doesn't work for low frequencies?  Are you still getting error 200141?

Thanks!

aNIta B

Applications Engineer

National Instruments

[cwilcox]

Thanks for the response.

What I have done is used the large range 2 counter continuous example VI to confirm function of my hardware. However when I switch back to the low frequency 1 counter continuous example VI, I get error 200141 immediately. I have remembered to change the PFI on my SCB-68 to match the counter configuration each time.

My board PCI-MIO-16XE-10 has two counters and my application has two square wave (RPM) inputs with ranges of 5-100 HZ and 100-2000 Hz respectively. I'd like to use the two counters to measure the two rpm's rather than build frequency to voltage signal conditioning circuits and use two analog inputs.

At this time I want to simply get the VI working and will use a 555 timer in astable mode to supply a 0-5v square wave. Once this is achieved I'll move on to my application. I've also been reading as much as possible on this error and still haven't grasped it. Any help on this matter would be greatly appreciated.

Thanks

Chris (beginner)

Message Edited by cwilcox on 02-03-2009 09:23 AM

[aNIta B]

Hey Chris,

           Are you using one of the shipping examples, like, Meas Dig Frequency-Low Freq 1 Ctr.vi, or a modified version of it?  Otherwise, would you be willing to post you code?

aNIta B

Applications Engineer

Naitonal Instruments

[Harinadh]

Hello,

I was trying to use NI 9401 to read the rpm of my flow meter,I used the same program which you people referred to in this thread and I get ERROR-200474,could some one please help resolve this problem.

I am a beginner and I am stuck with this.

Thanks,

Hari. 

[aNIta B]

Hi Hari,

        The error that you're getting is likely explained by this KnowledgeBase: Error 200474 With Digital Frequency Example VIs Modified for Continuous Acquisition.  Let me know if that doesn't answer your question!

[Mass0873]

hey i am using proximity sensor with connection to 14,16 and 1 pins of NI 9401.From test panel i checked sensor getting supply but when i run my labview program sensors light turns off and unnamed task error coming.Please help me.
Thanks

[National_Burritos]

Hi Mass0873,

I would recommend asking this question on a new or more current forum, as it is unlikely people will provide an answer.

In the meanwhile, I wanted to ask a few questions:

- Has this device worked before?

- What chassis are you using?

- What version of LabVIEW and DAQmx are you using (can be checked in NI MAX)?

- What is the error code you receive?

These should help with troubleshooting!

[MahsaY]

Hello. I found the topic very similar to my question. I have CRIO9045 and I want to measure the incremental encoder using NI9401  with DAQmax programming method. So the aim is to measure speed profile like what we have in the examples of sound and vibration tool kit for digital tacho in DAQmax. In the encoder there are two pulses A+ and B+ and one index pulse N+. There are different ways to start creating DAQmax channel for the NI9401. I chose Counter input -> Count edge. I'm enclosing my program here. What should I define for the counter and sample clock source? Indeed, I wired the index pulse of the encoder to the PFI0 of the NI9401. So I defined (Mode4/ctr0) for the counter and (Mode4/ PFI0) for the sample clock source since it asks for an external clock source and I cannot select the onboard clock of the CRIO. Would you please help me with how I can do measuring the digital encoder using NI9401 to get the speed profile? Thank you in advance.