Changing frequency measurement

Hello,
I´ve sampled a signal from a hall sensor on a belt pulley. I get six pulses per rotation. So I get a higher frequency on a higher belt speed.
How can I analyse the frequency or pulse width for each pulse with LV?
Best regards,
Andy

Andy,
Typically period measurements are used when pulse by pulse data is needed. You could either measure the width of a pulse or the period of a cycle.
In either case you need to define a minimum speed, or maximum pulse width or period you want to detect. When the shaft slows down the time between pulses or edges gets longer and longer. Make sure your period measurement process has some kind of timeout or maximum time limit so that it does not hang up waiting for another edge onyour signal.
Lynn

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Problems trying to change frequency band on Airport Express

I'm trying to solve drop-out issues, when playing music from I-tunes etc over airport express connected to stereo, by changing frequency band and channel on my Time Capsule-router with Airport Utility.
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Finally, when I restored original basic 8.2.11n setting, all returned to normal.
However, I'd like to try to solve my drop-put problems by remedies proposed elsewhere in forum, such as changing frequency band and channel. Does anyone know why I am having this problem changing frequency band and channel. My imac (which could not see TC on 5Ghs is pre-intel, mac-book has intel, both OSX 10.5.8.
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Thanks for reply. I tried again changing frequency to 2.4 as suggested, but the problem was the same. Airport Utility reports it cannot find device. Then, when I try to connect to wireless network anyway, a box comes up telling me to enter password. I do this and I get the message "connection failed".
Fortunately, I am able to wire my macbook into Time capsule by ethernet cable, and change it back to original setting, and all is well.
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Average Change Frequencies for addresses, bank information, ...

Hi,
I am working on a Data Quality project, which has - so far - nothing to do with BI.
Currently, I am trying to define metrics for measuring different aspects of data quality and one is how up to date data is. One indicator for that is checking the date of the last update and the interval between the previous updates against an average change frequency.
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<i>So I would like to know if maybe somebody knows if I could find such information in BI ?</i>
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Is it possible to add / change frequency bands to ...

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Solved!
Go to Solution.

It all comes down to what was available in the country at the time the system was developed. In Europe before GSM came along, each country had their own system (TACS, NMT, C-NET etc...) and own bands, but ITU tried to get all countries to harmonise, EU went further and made all countries clear a few bands of radio spectrum and work on a common system, hence GSM. Other countries though like USA had different band requirements due to historical usage by the millitary and other organisations and so couldn't reserve the same bands.
Today there are 4 GSM bands (5? if you count GSM railway) and most mid-range phones will support all 4, that allows you to contect in any GSM network. However if you have only a 2 or 3 band phone it isn't possible to change those bands as the hardware filters in the radio are fixed. When you go to 3G there is something like 9 bands defined. Some of these are in different areas of the radio spectrum, others use different channel numbering but very similar parts of the radio spectrum. In some cases those bands are the same as the standard GSM bands with the intention that in the future GSM in those bands might be switched off and 3G reused in those bands.
This is very much a simple summary of 30+ years of cellular development.

Can i change frequency of time machine backups

I haven't used TM since my Time Capsule died last winter, i was waiting for new wifi AC TC. since then i purchased a new imac. now i'm deciding between the TC and the Airport Exteme. TC seem slike no brainer due to cheaper memories. the problem is tha tmy new imac is obviously only WiFi N. my last N mac took FOREVER to update my TC...it slowed my computer and seemed to eat my wifi. So ideally i'd love to get the AX unit and then a thunderbolt extermal drive. Altough i now realize the cost of the thurderbolt option on these drives...sweet lord! (Is the tech really that expense? apple controlling distribution to keep sales of TC?) . i probably could have avoided this if i had the patience to wait for an AC imac...but i don't have that much control!
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To change the frequency of Time Machine's backups, you would have to use a tool like Time Machine Editor; however, Time Machine only keeps hourly backups for the past day, and then daily backups for the past week, followed by weekly backups indefinitely. This means that it does exactly what you already want, with the added feature of hourly backups that are cycled through. As was mentioned above, in most cases these wont take much space at all, so adjusting Time Machine's behavior for the sake of saving space will not do much in the grand scheme of things.

Changing frequency of invoice generation program

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Hello Susan,
Thanks so much for your response, it triggered the right thought in my head and I have been able to resolve the issue.
Many Thanks

Changing frequency of backups

at one time i had an app, i don't remember the name, that purported to change the frequency of TM backups. i don't really need hourly. all the app ever seem to do was prevent TM from ever backing up.
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Most of us are letting TM work as designed, because it usually is best that way, and the hourly incremental backups normally aren't very obtrusive.
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Triggering frequency measurement with 9402 and cDAQ

Hi all,
I'm trying to take a speed measurement off of a shaft using a hall effect sensor and a 9402 module in a 4 module cDAQ 9174 chassis. I've used the low frequency measurement example using DAQmx but if the shaft isn't spinning I get a timeout error.
Two questions, is there a way to use the Express VI's to accomplish this and how do I create a trigger to start the measurement?
-Ian

Why not clear the timeout and report 0 RPM. The timeout is 0 rmp but you dont want to wait forever and block program flow.
Paul Falkenstein
Coleman Technologies Inc.
CLA, CPI, AIA-Vision
Labview 4.0- 2013, RT, Vision, FPGA

Digital Frequency Measurement for cRIO

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Hello,
A great place to get started when using a cRIO is the NI CompactRIO Developer's Guide. It will explain both Scan Mode and FPGA. The difference between them comes down to the functionality and what you would like to complete in the program. The simpler of the two is Scan Mode but you have more functionality with FPGA.
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ni.com/support

Frequency measurements using NI cRIO 9073 and NI 9425 or NI 9422 modules

Hi everyone!
I'm trying to measure two frequency signals using a cRIO 9073.
I'm already using a NI 9425 module for digital inputs.
I need to measure two (2) frequency signals.
Is it possible to use this module (NI 9425) or NI 9422 for frequency measurements either in Scan Engine or FPGA mode?
In case it is, if you could point me to any example, it would be appreciated.
I'll try to be more explanatory:
These two frequency signals are in completely different ranges.
The first is a frequency signal from a DC motor tachometer and the second one is from a mass flow meter.
So the frequency ranges vary from KHZ for the tachometer output, to Hz for the MFM output.
The rest of the channels on the module are simple Digital Inputs.
Also, I have the option to use a NI 9422 module if NI 9425 is not appropriate.
Thanks in advance,
t81

t81,
It is possible to make frequency measurements with either the 9422 or the 9425 but each will have its own limitations in the range of frequency it will be able to accurately measure.
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1. What are the frequency ranges for each sensor (tach and MFM)? More than just knowing Hz/kHz will be helpful.
2. To what accuracy do you need to measure these signals?
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http://zone.ni.com/reference/en-XX/help/372603F-01/riohelprt/crio-9422_rt/
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Dan

Point-by-point Frequency Measurement

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Sorry for the mess of wires; that's what happens when I click the clean-up tool button!
Brian
Attachments:
DAQ.vi ‏27 KB

You can try the attached code.
Attachments:
point-by-point frequency estimation.vi ‏11 KB

Low frequency measurement from Parallel Port

Hi there...
I need to calculate the "on" and "off" time and duty cycle in pulse form from a parallel port. By making the circuit in 5 or 0 V, I just simply put it in my parallel port. The problem comes when I need to measure a very very low frequency. In this case, I want to measure the duty cycle from my operated refrigerator. I need to know when the thermostat goes "on" and when it comes to "off". In my experience, the thermostat will be "on" in about 5-10 minutes and "off" in about 20-30 minutes. So, the pulse might be take for a long periode each.
I've tried with Timing and Transition Measurement wizard or even by using Pulse Measurement.vi which is included in Waveform Measurement category. It only works for 2 Hz and . If I try to set it with 1 Hz or below, it comes the message :
"Error -20308 occurred at Timing and Transition Measurements -> Untitled 1
:4" (waveform index 0 of 1)
Possible reason(s):
Analysis: The waveform did not cross the mid reference level enough times to perform this measurement. Check the signal length, reference levels, and ref level units."
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Regards,
Ricki

here is a quick shot to give you an idea
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'
Attachments:
port logger.vi ‏22 KB

Frequency measurement with PCI6624, timout problem at startup, i.e measure 0 Hz.

I want to use my PCI 6624 for measuring of frequency signals from a gear flow meter. The problem is that when I start running the VI there is no pulses from the flow meter and the VI stops to run and I get a Timeout error message. I.e is it possible to measure 0 Hz with the 6624 input used for frequency measurement?
With hardware from IOtech and Daisylab I don`t have this kind of problem.
/Thanks in advance

Having similar problem,
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Labview Version 8.5
Labview Version 8.6
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Attachments:
FLOWMETER_21.vi ‏37 KB

PXI-6533, Changing frequency without stopping the card?

Using PXI-6533 and LabVIEW, is it possible to update the frequency (of a defined pattern) without stopping the output of the card?

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DAQmx Timing Property Node (VI)
http://zone.ni.com/reference/en-XX/help/370469AA-01/lvdaqmx/mxtimingpnode/
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Applications Engineer
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I have an optical sensor how do I get a RPM or frequency measurement?

I have three optical sensors on a gyroscope rig connected to
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I have to say I’m not having a lot of luck with the example finder. I have three optical sensors all hooked up to LabVIEW. I can count the pulses no problem, I just don’t seem to be able to connect a clock. As I think I want a “Period Measurement” or a “Buffered Period.”
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Robert

Changing frequency measuremen​t

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Changing frequency measurement