Problem measuring frequency with PXI-4472 module

Hi all,
I am using PXI-4472 DSA Module to analyse the Frequency.
I am using LAbVIEW 7 software.
I am using the Spectral Measurement VI in Signal Analysis in Functions.
Using that i am not bale to measure the frequency more than 500Hz.
My card is able to measure upto 50KHz.
why it is happening?
what i need to do if i want to measure the frequency upto 50KHz?
regards
Preetam

What happens when you try to measure a signal more than 500Hz? What does the time domain signal look like? How fast is the NI-4472 sampling? Are you using a sensor such as a microphone? Or are you just making voltage measurements?
I would recommend starting on the acquisition side with a shipping DAQmx example such as "Cont Acq&Graph Voltage-Int Clk.vi" which can be found through the LabVIEW Example Finder under the DAQmx section. You will need to have at least NI-DAQ 7.1 to use DAQmx with the 4472, but it's always good to upgrade to the latest version. Here's a link which shows the latest versions of DAQ on a per device basis:
http://www.ni.com/support/daq/versions.htm
Once the time domain data looks good, then try to add the signal processing.
Let me know how it goes.
-Jack

Similar Messages

How can I measure RPM with CTR-500 module?

I have used the CTR-500 module for mesurement of motor RPM. But it doesn't have direct option to measure RPM ,
so i have count pulses for 1sec (then reset the counter) and by calculation show the result for 1min. But it varies every time ,cant give me fix RPM.
I want reliable solution for this.

min
You have not said how much the RPM actually varies from reading to reading and what the range of measured RPM is for the process. This variation can be caused by a couple of things. One would be actual variations in RPM due to changes in motor loading. What is this motor driving? Most RPM readouts use some form of sample averaging to smooth out the readings.
A second cause could be your vi. Suggest you post a copy of your vi.
In case you have not seen it, here is a link to a KB about measuring frequency with cFP. It also links to several other docs on the same subject . http://digital.ni.com/public.nsf/allkb/D8DB42F9FDC3607E862568640047F144?OpenDocument

How to measure frequency with PCI-4474 card

Hi,
I'm trying to measure frequency with PCI-4474 card.
Any sample code available?
Thanks.

Hi,
Thank you for posting the the NI forums. There aren’t any example programs that ship with the DSA drivers. Will you be using this with the Sound and Vibration Toolkit? If so, there are numerous examples that install with this software package. Check out the LabVIEW Example Finder >> Toolkits and Modules >> Sound and Vibration Toolkit.
In addition to this, you could also use the signal processing VIs that ship with LabVIEW. There are also examples that ship with LabVIEW that use these VI in Example Finder >> Analyzing and Processing Signals FFT and Frequency Analysis. There is an entire Signal Processing palette that should contain the functionality that you need.
I hope this helps. Post back if you have further questions.
Ed W.
Applications Engineer
National Instruments

Can I measure frequency with a SCXI-1120 module and SCXI-1320 terminal block?

I am attempting to measure a square wave from a directional encoder to display RPM of a dynamometer. The waveform will have a frequency of 0-4KHz, with 3.6KHz being nominal, at about 5volts RMS. How can I measure the frequency of this waveform with the hardware I am currently using? In addition to what is listed above, I am using a PCI6034E GPIB card and LabView software.

In order to measure frequency, I would not recommend to use the SCXI-1120, but the SCXI 1126, which is a programmable isolated F-to-V module.
If by any reason you do not want to use SCXI-1126, then I would suggest to use the counter/timers of your board. The counter/timers are TTL compatible, and are the devices that we mostly recommend for doing precise frequency measurements.
In order to have access to the counter/timers of your board through your SCXI chassis, you will need SCXI-1180, which is basically a feedtrhough panel for your DAQ board.
Once we have access to the counter/timers through the SCXI chassis, we can proceed with the coding.
I found a pretty good webpage that clearly explains how to perform frequency measurement with the DAQ-S
TC counter/timers (DAQ-STC is the type of counter/timer chip that you DAQ device has). Here is the link to it:
Pulse Width & Frequency Measurements
As you will see, this link contains tutorials, application notes and example programs. I would recommend to pay special attention to the example program called: DAQ-STC: Measuring frequency.
Good luck with your application!

Scxi 1126 frequency measurement along with other scxi modules

I want to measure frequency signal using sxci 1126. I have gone through the example code for sxci 1126. I am using NI-DAQ and Labview 7.1.
The example code is applicable when am acquiring only from 1126. I have to acquire data also from 1102 102B along with 1126.
In the example code along with AI config.vi and Ai Start.vi there are two additional vi's like AI paramete.vi and AI Trigger config.vi I understand that they are used for reading from 1126. My worry is how this is going to affect my acquisition from other scxi modules as all the modules are in multiplexed mode.

Hi Bipin,
Looking at your code, I see that you are still using Traditional DAQ. Since you have LV 7.1, you can take advantage of the new features of DAQmx.
With DAQmx, you can create a virtual task that includes all of the different types of measurements you want to make. Once you set up the task in MAX, you can place it on the block diagram and automatically generate the code necessary to execute this.
To do this, open up the Measurement and Automation Exlporer (MAX). Select "Data Neighborhood" from the tree on the left. Then click the button labeled "Create New." Create a DAQmx Virtual Channel. Follow the series of menus to set up your first type of acquisition (1126 frequency measurement). When you are
done creating the task, you can add the second type of measurement to that same task. In the task config page, you will see a white box with the name of the channel you just created in it. Above the name you will see an "Add" button. Click on this button and follow the menus to set up your second measurement (1102 module).
Once they are set up, save the task and open LabVIEW. Place the DAQmx Task Name constant on your block diagram found in All Functions >> Data Acquisition >> DAQmx... the task name constant is a purple colored box. Clicking on the box once its on the block diagram will expand a menu that will let you choose your task. Once selected, right click on the task name and choose Generate Code >> Example. This will automatically generate the code necessary to run the tasks. Simply hit the run button and enjoy!
Thanks,
Sal

Measure frequency with 2 counters

Hello,
I'm measuring a digital frequency signal using a PXI-6602 module using the 'high frequency with 2 counters' method. From the examples I have found, it seems that you specify only the counter which is doing the measuring and the measurement time. How does LabVIEW know which counter is used to generate the HF pulse reference train, for example:
ctr 0 - measuring 200kHz signal
ctr 1 - generating 50kHz signal
Do I independently set up and start the ctr1 generation, and as log as it starts before the measurement commences, does LV then sort it all out without any other input?
Thanks
Dave

You should connect the signal (whose frequency needs to be measured) to Ctr-1, and there gonna be an internal connection between the output of the first counter and the gate of the second counter (as described here).
You may want to check this link as well.
I am not allergic to Kudos, in fact I love Kudos.
Make your LabVIEW experience more CONVENIENT.

Measuring frequency with counter or analog input?

I have some frequencies which I need to measure. Some signals are digital and some are analog.
I have a PXI-6040E DAQ which has both counters and analog inputs.
I heard that you can measure higher frequencies with the counters than with analog inputs.
What is the range of frequencies an analog input can determine versus a digital counter?
Where is the cutoff that you must absolutely use a digital counter to determine the frequency?
Is the cutoff different for different DAQ cards? Or is generally the same.

Have you looked at the specs for the device? The max sample rate and the max counter input will be listed there. The max frequency for an analog input is based on nyquist sampling theory. Are you at all familiar with? It states your sampling frequency has to be at least twice the frequency you are measuring.
Since each device might have a different max sample rate, your last question is answered.

Above-High-Level Triggering Mode with PXI-4472

In the PXI-4472 User's manual (April 2003 edition), Figure 3-9 shows a trigger that is active when an analog input is above a specified high Value. To which trigger is this figure referring? Also, I have seen the Configure_HW_Analog_Trigger function but do not see a VI that accomodates this function. I would like access to this trigger that is always high when the analog input is above a certain level.

These triggers are analog level triggers that are taken directly from one of the analog input channels. In LabVIEW, the DAQmx Trigger.vi can be configured to the trigger type that you need. In the shipping examples (Help >> Find Examples) for LabVIEW, a good example to look at would be Acq&Graph Voltage Int Clock Analog Start.vi.
For Traditional DAQ, the AI Start.vi is used to configure the trigger. The example Cont Acq&Graph(buffered) Hard A-Trig.vi is a good referrence for that. Hope this helps.
Best Regards,
Jeremy R.
NI - Applications Engineer

Counter to measure frequency with multiple channels (Analog In/Out) in one vi

Hi,
I am using DAQ 6062E. I have multiple channels: an Analog In, Analog Out, Count Edges, and Count Frequencies. Without Count Frequency, the program works fine, I have defined a Sample Clock for each channel and then a common sampling rate. When I add Count frequency channel, I am not able anymore to use Sample Clock, since I get an error that Sample Clock can not be used, and if I change the Sample clock of the Count frequency to Implicit, then I can not connect different channels with a same sampling rate. In the attached file, if the Count Frequency is not connected to any Sample clock and sampling rate, the program works, but now I can not run the program for more than 5-10 Hz sampling rate, otherwise I get the error: 209802 “occurred at DAQmx wait for next sample clock, slow down the sample clock”. Does anybody know how to fix this problem?
Thanks a lot,
Azadeh
Attachments:
multiple channel.jpg ‏117 KB

Hi Otis,
Thanks for looking at the problem. I ran just two counters in a same vi. I was not able to use the Sample Clock since I needed to define an external sample clock source. The vi is attached. I could run this vi fast (200Hz). So, I am not sure why when two counters are combined with AI/AO the rate is very slow. I have attached three vi(s). Just two counters, AI/AO/1 counter, and AI/AO/2 Counters vis. I am able to run the vis in 200 Hz except the vi with AI/AO/2 counters (maximum sampling rate 20Hz). I appreciate if you can look at it if I am missing something.
Thanks,
Azadeh
Attachments:
AI_AO_2 Counter.vi ‏153 KB
2 Counter.vi ‏61 KB
AI_AO_1 counter.vi ‏138 KB

Can I measure voltage with a current module by removing the resistor?

I'm trying to measure a 0-10 VDC signal and I don't have any voltage throughput modules for my 2345 signal conditioning unit. I do have some SCC-CI20 (4-20mA) input modules that use a 249 ohm resistor. The output from these modules are 1-5 VDC as expected. I'm wondering if I remove the resistor do I not have a voltage module?
Please help, I need to get some measurements done soon.
Thanks

Hi,
Yes, you can use the CI20 module to read in voltages. Connecting a voltage source in parallel with R3 will result in the same potential drop to appear across the R3 resistor (see diagram attached).
Make sure that you DO NOT configure the CI20 in the Measurement and Automation Explorer, so you can read the raw voltage. Also DO NOT supply more voltage than 5V, or you might damage the module.
Hope this helps,
Lesley Y.
Attachments:
CI20 Connection for Voltage.gif ‏38 KB

Trying to measure frequency with the cFP-CTR-502. Can't get tutorial to work!

Hello,
I am trying to measure the frequency of a
signal that I'm counting using the cFP-CTR-502. I can successfully
count pulses but I what I really need to know is the RATE of counts
(counts/s or the frequency). I have found some Labview programs that
supposedly do this that I've downloaded from ni.com (link below). The
concept makes sense of using a gate and output but the programming is
crazy - at least the program in the link below is.
1. Is there an easier way to measure the frequency of counts?
2. Why will the program from the link below ( frequency_measurement__ctr_.vi
) not work on my system? I get an error everytime I run it. Could I be
missing some VI's necessary for it to run? Or is it from another
LabView version that is not compatible?
The
entire error is: -32810 occured at FieldPoint initialization failed.
Possible causes, 1. Missing or corrupt configuration file; 2. Failed to
create call backs. : FP Open.vi
Link for program: http://sine.ni.com/devzone/cda/epd/p/id/4682
Thanks in advance for all your help and time!
Sam T

Sam,
Have you tried the example titled Frequency Measurement.vi that ships with LV?

How to Measure frequency of less than 300 Hz

Is it possible to measure frequency without a counter module? All I have is a cDAQ with 9205, 9221 and 9263 modules.

Hello,
I am assuming that you want to measure analog frequency, since you have analog input and output hardware. There is a useful LabView Help file titled Measuring Analog Frequency. You will be able to measure analog frequency using just software and no counters. However, this involves using Fast Fourier Transform (FFT) functions that are only available in LabView Full and Professional versions. Please also take a look at the examples in the Example Finder. Some helpful ones are titled … Signal Generation and Processing.vi, Spectrum Measurements.vi, and Simple Spectrum Analyzer (sim).vi. These example’s block diagrams are a little busy, however you can see how they are using simulated signals with the FFT Power Spectrum.vi. Note that the example titled Spectrum Measurements.vi uses express functions. These functions are going to involve less programming, but offer lower program efficiency.
Samantha
National Instruments
Applications Engineer

Pins at a PCI MIO-16E-1 to Measure Frequency(DAQ-STC).vi?

I want to measure frequency with the
"Measure Frequency(DAQ-STC).vi".
Can't find the appropriate connector pins
in the manual of my PCI MIO-16E-1.
Can someone confirm or correct me?
Signal - PFI1/GPCTR1_SOURCE
SignalGND - PFI9/GPCTR0_GATE
PFI8/GPCTR0_SOURCE - PFI4/GPCTR1_GATE
Thanks in advance
Manfred

Manfred,
You can find this information by going to the http://www.ni.com/manuals site and viewing the E-series manual. There is a table which shows the pin number, name, and function for each pin.
Pin 10 - PFI1/Trig2
Pin 11 - PFI0/Trig1
Pin 43 - PFI2/Convert
Pin 42 - PFI3/GPCTR1_Source
Pin 41 - PFI4/GPCTR1_Gate
Pin 40 - GPCTR1_out
Pin 6 - PFI5/Update
Pin 5 - PFI6/WFTRIG
Pin 3 - PFI9/GPCTR0_Gate
Pin 2 - GPCTR0_Out
Pin 4,39,35,36 - DGND
Mark

I need to measure the frequency of a signal on Pin 39 (PFI 15) of a PXIe-6361 module.

I need to measure the frequency of a signal on pin 39 (PFI 15) of a PXIe-6361 module. All of the digital I/O pins are already assigned and in use. The signal frequency range is 50KHz to 500KHz. I have tried all of the sample programs for DAQmx Counter/Timer frequency measurement. If I modify them to use my hardware, I get run-time errors with conflicts with resources already assigned.

Hi Julia,
Thanks for the response. As I stated before, I have tried all of the examples available that apply. There are only three and one of those uses two counters. The two I have tried are:
Examples/Hardware Input and Output/Counter Measurements/Digital Frequency/
DigFreq-Buff-Cont-ExtClk-ArmStart.prj and
DigFreq-LowFreq1Ctr.prj
These examples default to using what appears to be traditional DAQ hardware (Dev1/ctr0 and /Dev1/PFI0). I changed the counter to mine (/PXI1Slot3/ctr3) and directed my signal source (PFI15 on pin 39) to the counter. No matter what I tried would not run. They would always compile but gave run-time errors ranging from resources already in use to “external trigger required”. I have no external trigger source and, if I did, there is no indication of how to assign it to the counter. NI has a very good X Series Users Manual that tells all of the great things you can do with the hardware, but there is NO CLUE how to do any of those things!!!! I know that some NI DAQmx functions use hardware resources that they never tell you about. I discovered that when trying to produce a single output pulse from a timer using counter #0. (Which, by the way, no one at NI could tell me how to do it.)
Measuring frequency should be very simple. The unknown signal is routed through a precise gate to a counter, and then the counter is read. NI DAQmx uses the opposite approach of using my signal as the gate and counting their internal source. However, the examples would not let me use the internal reference sources.
To answer your other questions, I am not performing any other measurements at the same time and the counter is not being used for anything else, period.
Any help would be greatly appreciated. Thanks again.
Wayne K.

Hi, iam facing proble in synchronizing 4 ni 4472 cards input with pxi -6052e analog output. please help me out to sort out this problem

hi, iam facing problem in synchronizing 4 ni 4472 cards input with pxi -6052e analog output. please help me out to sort out this problem

Hi achyuth,
Thank you for posting on the National Instruments forum.
I am not sure what you are trying to do. Are you trying to input and output at the
same time? Are you just trying to
synchronize all of your inputs? Do you
want them to run off the same clock? If
you could, give me some more information so I can understand your problem
better.
In the meantime, this might help you:
PXI Timing,
Triggering, and Synchronization Capabilities of E-Series Multifunction Data
Acquisition ...
PXI Timing and Synchronization
Thank You,
Nick F.
Applications Engineer

Problem measuring frequency with PXI-4472 module

Similar Messages

Maybe you are looking for