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

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Measure time of an measurement and if measurement time is less than 90 second wait until 90 second and then proceed to next steps or stop.

Hi
I am trying to make a program
      During execute a measurement count the time.
      If measurement time is more than 90 second proceed to the next steps (or stop the measurement)
      If measurement time is less than 90 second, wait until 90 second and then proceed to next steps or stop
I appreciate deeply if some help me.

What sort of measurement are you talking about? What affects the time of your measurement? The very basic description you have is of a state machine and there are numerous examples of that
1. Actually I would like measure the time of "Alignment" function done by wafer test equipment name Prober ( the model is "UF3000" made by TOKYO SEIMITSU CO., LTD.
2.. Right now the "Alignment" function is started when a GPIB command is written as "N" and wait for resposne 70 in polling.
Please refer to the attachment for Alignement function if it help you.
In the attahement
For Alignment error delay we are using =600
Alignment counter =30000
align loop cnt = 30000
This is a program wriiten by another person and he is not availabe any more. What I am trying to do is
1. During execute a "Alignment " function count the time.
2. If  "Alignment " function time is more than 90 second proceed to the next steps
3. If "Alignment " function is less than 90 second, wait until 90 second and then proceed to next steps
Attachments:
Alignment function.xlsx ‏153 KB

How to measure frequency

hi i have made FM Jamer circuit in multisim 13 , my circuit image you can see below , now i want to measure the Measure Frequency which is Generated it L1 Inductor , so i do not know how to measure frequency in multsim , please help me , or also it would be good to use Antena instead of inductor or not , i have not see any Antena component in multsim 13

Hi Zahis,
The measuring probe measures frequency, this video shows how you can use a probe in Multisim:
http://www.youtube.com/watch?v=xKEQ3EXEaP8
Tien P.
National Instruments

How to measure frequency when no static line

Hi. I think to directly measure frequency using DAXmx function my input signal should be connceted to DAQ PFI Lines but in my application the clock frequency is outputted on P0.0 line . Is there any way to directky measure frequency uding DAQmx function or I should do it manually?
Thanks

Hi tintin,
you really should have learned to post good ( read as: meaningful, with sufficient explanations and background information) questions after more than 200 posts in this forum…
What frequency do you want to measure?
What is the relation to outputting your own "clock frequency" on some DO pin?
Which hardware do you use?
Why do you need to measure a signal frequency when you know that frequency as you output that signal?
How do you measure frequencies "manually"?
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

How to Measure Frequency to RPM NI-DAQmx Tasks

Hello,
I am trying to measure frequency using NI DAQmx task and then convert this to an RPM if at all possible.
I have the following hardware options at my disposal.
I have SCXI 1126 Module along with a SCXI 1327 terminal, as well as a PXI 6289 Multifunction DAQ.
I have wired in a mag sensor to ai7 on my 1126 and when I pass a metallic object I get a amplitude of 6 - 8 so I am able to read the mag sensor.
What I am trying to do is to somehow convert this analog measurement into a RPM while only utilizing the NI DAQmx task.
Any help would be appreciated.
Tim
Solved!
Go to Solution.
Attachments:
Freq Set Up.jpg ‏2993 KB

So I would select new in "Custom Scaling"
Then would I select linear?
Your calculations are simple but I am unsure if this would give me the desired result. From my attachment I am seeing an input amplitude of 6 Hz for each pulse. What I mean by this is that every time I bring a ferrous object near my mag pick up I get a pulse, this is what I was trying to illustrate in the attachment. The analog pulse comes in a 6 Hz so I would simply multiple this pulse by 60 (assuming I get one pulse per rotation) to get RPM?
How would this make sense if I only input one pulse for a long duration of time?
I have notice the amplitude of the pulse input increases with increased pulse frequency. Does this mean the lowest RPM I can record is 360 RPM?
Tim

How to make stills duration less than 00:00:00:01 ?

Hi,
This may seem an odd request, but I have a sequence of several stills of a propeller blade on a model, sort of time lapse, move and photo etc, which when played together rotates the prop. They are currently set to 00:00:00:01 and play loop sees a very slow rotation. I thus need to make them even less than that duration. Is that possible and how is it done ? They currently form the project. R/click duration and altering 01 to 001 doesnt work, the last two numbers being frame number and 25fps is the project value.
Perhaps I need to make the project more than 25fps, so that 00:00:00:01 which means 1 frame I presume, will be seen as far less of a second than 1/25th ? How do I set project to a higher fps if this is the solution ? Then would I save out or export the finished film as a 25fps clip to use elsewhere ?
I also found it silly that I had to right click on each stills clip in timelie and choose duration. I tried selecting all of them and r/click duration but duration was greyed out. If I had a lot there, surely there must be a way of making all their durations the same amount at once ?
I am unable to zoom the timeline to drag their size less.
Envirographics

Hi,
Thanks for the sugestions.
I have not yet transferred a Sequence, I have created a second sequence and dragged it out as a floating window, then dragged a selection box across my stills and dragged them over to it, but no doubt this isnt the way to make them all a combined duration of say 1 frame. They still have separate properties. How is it done such that I can give them as you say one duration for the entire lot.
AE no doubt is After Effects. another purchase. Working on it !
Envirographics.

How to report only quantities less than zero on a calculated field

I do not understand why my text will not work when it comes to reporting only 'Missing POs' less than zero, I assume it is because I am using 'int' on some fields?
Any advice?
SELECT
t0.father as 'Parent Code',
t2.itemname as 'Parent Description',
t2.frgnname as 'Parent Status',
t0.code as 'Child Code',
t1.itemname as 'Child Description',
t1.frgnname as 'Child Status',
t0.comment as 'Master',
cast(t3.onhand as int) as 'Child Uncommitted Stock',
cast(t3.iscommited as int) as 'Child Committed Stock',
(cast(t3.onhand as int) - cast(t3.iscommited as int)) as 'Child Free Stock',
cast(t3.onorder as int) as 'Purchase Orders',
(cast(t3.onhand as int) - cast(t3.iscommited as int)) + cast(t3.onorder as int) as 'Missing POs'
FROM
itt1 t0
inner join oitm t1 on t0.code = t1.itemcode
inner join oitm t2 on t0.father = t2.itemcode
LEFT JOIN OITW T3 ON T3.WHSCODE = T0.Warehouse AND T3.ItemCode = T0.Code
Where T3.WHSCODE Like '[%0]%' and 'Missing POs' < 0
ORDER BY
'Missing POs' asc, t0.father, t0.code
Many thanks,
Robin (I will be awarding points on all my outstanding questions shorlty - management time pressure at mo!)

Try this:
SELECT
t0.father as 'Parent Code',
t2.itemname as 'Parent Description',
t2.frgnname as 'Parent Status',
t0.code as 'Child Code',
t1.itemname as 'Child Description',
t1.frgnname as 'Child Status',
t0.comment as 'Master',
cast(t3.onhand as int) as 'Child Uncommitted Stock',
cast(t3.iscommited as int) as 'Child Committed Stock',
(cast(t3.onhand as int) - cast(t3.iscommited as int)) as 'Child Free Stock',
cast(t3.onorder as int) as 'Purchase Orders',
(cast(t3.onhand as int) - cast(t3.iscommited as int))
+ cast(t3.onorder as int) as 'Missing POs'
FROM
itt1 t0
inner join oitm t1 on t0.code = t1.itemcode
inner join oitm t2 on t0.father = t2.itemcode
LEFT JOIN OITW T3 ON T3.WHSCODE = T0.Warehouse AND T3.ItemCode = T0.Code
Where T3.WHSCODE Like '%0%' and (cast(t3.onhand as int) - cast(t3.iscommited as int))
+ cast(t3.onorder as int) < 0
ORDER BY
(cast(t3.onhand as int) - cast(t3.iscommited as int))
+ cast(t3.onorder as int),t0.father, t0.code

How to measure frequencies of two sources simultaneously using 6602?

I am using pci-6602 & LabView to measure frequencies of two sources. I wired Measure Frequency (NI-TIO).vi to do it, but it seems the counter only works at one channel at a time. Can anybody send me an example vi?
Many thanks in advance
ZYuan

Hi ZYuan,
To measure the frequencies simultaneously, you would need to duplicate the code for the single counter example twice and link the error cluster from one set to the next. I don't have a specific example but the following example can be used as a guide.
Simultaneous Buffered-Event Counting on All Eight Counters of the 6602 or 6608 Devices
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3DC9F56A4E034080020E74861&p_node=DZ52325&p_source=External
Hope that helps. Have a good day.
Ron

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

How to get 1 day less than user entered date

Hi
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Thanks
Suja

Hi Suja,
You can use Less Than and Greater than for a user entry variable as follows: When you right click > restrict the char, then in the pop up box there is a drop down for Selection. Choose Value Hange here. Then in the drop down to the right you will have values ike Between, Less Than, Greater than...you can select as required.
Hope this helps...

How to measure frequency by USB 6211?

Dear all,
I'm using USB 6211 to measure the input analog voltage signal, then use a counter to yield the frequency. Please find the VI figure in the attachement.
The problem is the insteal of measure the right frequency, which is from 300Hz to 1000Hz. There is a lot of high frequency noise from thousand to milliion Hz. I think it pick up the high frequency harmonics. How to avoid it or use a more effective way to achieve the measurements.
Regards,
Alan
Attachments:
flow rate frequency measurement.JPG ‏43 KB

You have to suppress high frequencies on the analog side of your signal. You must set it to a frequency which is not higher than half of your aquisition rate. If you sample with 10 kHz your filter must have a cutoff frequency of max. 5 kHz. Otherwise you will see the signal mirrored at the half of the sample rate. A 6kHz signal will lead to a 4 kHz signal after the sampling.
Waldemar
Using 7.1.1, 8.5.1, 8.6.1, 2009 on XP and RT
Don't forget to give Kudos to good answers and/or questions

How to measure frequency using daq 6009

HAI..
Im using PFIO line to measure the frequency..i have attached my vi along with this..output is read approximately to the given input when i highlight the execution,but when i use run and run continuosly alone,am getting incorrect values..im totally confused..suggest some ideas..
another doubt, may i use analog port to measure the frequency of an oscillator?if so kindly help me to create a vi for this also..
Attachments:
counter.vi ‏19 KB

From your VI, one thing is clear, you are creating a task, but you are not clearing it. Please take a look at this example:http://decibel.ni.com/content/docs/DOC-8172

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How to Measure frequency of less than 300 Hz

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