Tachometer signal to RPM in DIADEM

Is it possible to generate rpm signal in DIADEM and how to change the reference value (sound pressure to db in order tracking tracking calculation)? Thanks

Hi there,
DIAdem is intended to find data, to analyze data, to run analyses, to create reports, and combine all functions to a script. Data is not generated in DIAdem. If you have an rpm signal that you would like to read into DIAdem for analysis, you would use the DIAdem NAVIGATOR to load this data into DIAdem. In the ANALYSIS tab, you will be able to run the data through an equation to convert from sound pressure to db. To help you begin the process of importing data and analyzing the data, please refer to DIAdem Help->Contents->Basics->Navigator and Analysis.
If you have any further questions, please give a specific instance or describe in more detail what you would like to do. From what I am understanding of your post, the answer is yes, you can use the Analysis tab to convert data, yes you can import signals that already exist into DIAdem. Please post back if you have any further questions and good luck with your project!
Regards,
Jackie
DAQ Product Marketing Engineer
National Instruments

Similar Messages

CRIO9215 for digital tachometer signal?

Hi, may i know if it is possible to for the cRIO9215, which an analog input module for compactrio to read in a digital signal from a tachometer?
Thanks Thanks!!

Hi,
You shouldn't have any problem reading a digital signal with the cRIO-9215.
Just keep in mind that you are reading a digital signal with an analog
line, so you will need to do some sort of logic on the analog signal to
determine if it's a true or a false. As long as you don't exceed
rates of about 10kS/s on your tach, then you shouldn't have a problem
reading the signal.
Another thing to keep in mind is that according the Operators Manual
the cRIO-9215 can only handle +/- 30V. Since some tachs may
output signals greater than that, you may want to optically
isolate the tach from the cRIO device.
As long as your signal is within a readable range (+/- 10V) there is no
real different between an analog signal and a digital signal as far as
the analog to digital converter is concerned.
Regards,
Otis
Training and Certification
Product Support Engineer
National Instruments

Tachometer time synchronized with waveform time

We ran into an issue trying to record both the speed/time from the OAT
Tachometer.vi
and waveform data from our other channels. The problem is that the
time shown in the waveform data is different from that in the tach
signal. I need to make sure my tach signal rpm data is synchronized
with the data I recorded from my other channels (pressure, temp, etc).
I am recording data to two different excel files using two
different Write Labview Measurement.vis. I have the "enable" switches
tied together. I record the data to excel from my .dat files. Since
the tachometer signal does not send "0 rpm" there is nothing in the
excel file until I have a speed profile. So I wait to record until I
have a clear speed profile around 120 rpm and then record data. Once
in the excel files, I subtract the offset from the tachometer signal
(Excel file #1) and the other waveform data (Excel file #2) so that
both start at time zero. I get about 0.5s extra recorded samples from
#2. Why do #1 and #2 not match? Is there any way I can ensure that
the data I am taking is occurring at the same time and one set does not
lag the other?
Thanks.

Hi all
I also had a similar problem. In my VI, I want to acquire a waveform, starting from the moment when the speed goes over a threshold.
I have a loop that acquires a every iteration 1.5s of waveform and computes speed profile, then tries to cut the waveform when the speed exceeds the threshold value.
Unluckily, watching the speed profile generated by the VI "OAT Analog Tacho Process" (whose reset connector is set to FALSE) I can see that the time values are not in phase with the acquisition timelenght.
To give an example, at the 4th iteration of the loop, where I would expect values between 4.5s and 6s, usually the speed profile has a timelenght ranging from a bit more than 3s to 4.7s, which means, it is not a problem due to the loss of a cycle for initialization issues, otherwise its points would stay inside the range 3s-4.5s
I thought it could be a problem of buffer underflow, but even increasing the buffer lenght doesn't solve the problem.
May it be an effect of the interpolation in the computation of speed profile? Or do I lose some samples during the loop? (I close the acquisition channel only at the end of the VI, in every loop I just call the read VI)
Thanks in advance

Myrio tachometer implementation

I am building an automotive data logger using a myrio and am looking for the best way to get tachometer RPM data onto the myrio.
The output sinal I have is a 12V square wave. So if I were to using an analog read It would need some kind of voltage divider to scale it to about 5V. But can an anlog input have a high enough frequency to not miss any data. I believe at red line of the max frequency I will need to read is about 250Hz. So I would need to log at over 500 Hz and still have enough overhead for other functions I have in my code.
I would guess a better way to do this would be using the fpga to find time between pulses to calculate rpm. But I am not sure how to wire this with the existing 12V tach signal.
Another option would be a seperate magnetic or optical tach device that a mount on my engine which would be a last resort effort if I can not using the exisiting signal.
Any suggestions to accomplish this would be greatly appreciated!

Hey Cyotani,
I found this example that I thought could be useful to give yourself an idea about how could you get started with the application:
"Decoding Tachometer Signals Using CompactRIO/LabVIEW FPGA"
http://www.ni.com/example/27326/en/
Also here a good article to take in count some considerations about it:
"Decoding Tachometer Signals Using CompactRIO and LabVIEW FPGA"
http://www.ni.com/white-paper/3230/en/
Hope this can be helpful,
Regards!
Daniel C.

I am using the Order Analysis Toolkit and want to get more information about the compensation for "Reference Signal Processing", which is scarce in the manuals, the website and the examples installed with the toolkit.

I am using the Order Analysis Toolkit and want to get more information about the compensation for "Reference Signal Processing", which is scarce in the manuals, the website and the examples installed with the toolkit.
In particular, I am analyzing the example "Even Angle Reference Signal Processing (Digital Tacho, DAQmx).vi", whose documentation I am reproducing in the following:
DESCRIPTIONS:
This VI demonstrates how to extract even angle reference signals and remove the slow-roll errors. It uses DAQmx VIs to acquire sound or vibration signals and a digital tachometer signal. This VI includes a two-step process: acquire data at low rotational speed to extract even angle reference; use the even angle reference to remove the errors in the vibration signal acquired at normal operation.
INSTRUCTIONS:
1. Run the VI.
2. On the DAQ Configurations tab, specify the sample rate, samples per channel, device and channel configurations, and tachometer channel information.
NOTE: You need to use DSA PXI-447x/PXI-446x and PXI TIO device in a PXI chassis to run this example. The DSA device must be in slot 2 of the PXI chassis.
3. Switch to Extract Even Angle Reference tab. Specify the number of samples to acquire and the # of revs in reference which determines the number of samples in even angle reference. Click Start to take a one-shot data acquisition of the vibration and tachometer signals. After the acquisition, you can see the extracted even angle references in Even Angle Reference.
4. Switch to the Remove Slow-roll Errors tab. Click Start to acquire data continuously and view the compensate results. Click Stop in this tab to stop the acquisition.
ORDER ANALYSIS VIs USED IN THIS EXAMPLE:
1. SVL Scale Voltage to EU.vi
2. OAT Digital Tacho Process.vi
3. OAT Get Even Angle Reference.vi
4. OAT Convert to Even Angle Signal.vi
5. OAT Compensate Even Angle Signal.vi
My question is: How is the synchronization produced at the time of the compensation ? How is it possible to eliminate the errors in a synchronized fashion with respect to the surface of the shaft bearing in mind that I am acquired data at a low rotation speed in order to get the "even angle reference" and then I use it to remove the errors in the vibration signal acquired at normal operation. In this application both operations are made in different acquisitions, therefore the reference of the correction signal is lost. Is it simply compensated without synchronizing ?
Our application is based on FPGA and we need to clarity those aspects before implementing the procedure.
Solved!
Go to Solution.

Hi CracKatoA.
Take a look at the link bellow:
http://forums.ni.com/ni/board/message?board.id=170&message.id=255126&requireLogin=False
Regards,
Filipe Silva

FFT in diadem

Hello,
I found some information from the DIAdem help and DIAdem manual as follows.
"Note DIAdem calculates the FFT to powers with a base of two and therefore might not use all the measurement data. Example: If a time signal has 340 values, DIAdem only uses the first 256 (28) values for the FFT."
"DIAdem calculates a FFT for the entire length of the specified channels, even if the channel length is not a power of two."
I don't understand which one is right?

Hello xzhcong,
They are both right, but I agree this is a little misleading.
The original FFT calculation did require a power of two number of values, but it has since been replaced with the improved DFT calculation (and can be switched back to the original algorithm with a configuration setting in DIAdem).
The setting can be changed from the "Settings" menu in DIAdem, in the Settings > Options > General dialog under "Compatibility"
That setting Specifies whether DIAdem uses the improved FFT algorithm. If the variable has the value TRUE, DIAdem uses the new algorithm.
Description:
Note If the variable has the value FALSE, DIAdem uses the FFT algorithm from DIAdem 10.0 and earlier. DIAdem calculates the FFT of the older FFT algorithms to powers with a base of two and therefore might not use all the measurement data. Example: If a time signal has 340 values, DIAdem only uses the first 256 (28) values for the FFT.
Only use the older FFT algorithms if you want to compare your results with earlier data. The functions ChnFFT1, ChnFFT2, and ChnInverseFFT including the related dialog boxes FFT with one time signal, FFT with two time signals, and Inverse FFT are affected by these changes.
The default setting for this variable is True, so the new algorithm will be used unless you specify otherwise.
Please check the attached PDF for more details about the FFT calculation ...
Let me know if you have additional question,
Otmar
Specifies whether DIAdem uses the improved FFT algorithm. If the variable has the value TRUE, DIAdem uses the new algorithm.
Definition
UseNIFFT, Boolean variable
Note If the variable has the value FALSE, DIAdem uses the FFT algorithm from DIAdem 10.0 and earlier. DIAdem calculates the FFT of the older FFT algorithms to powers with a base of two and therefore might not use all the measurement data. Example: If a time signal has 340 values, DIAdem only uses the first 256 (28) values for the FFT.
Only use the older FFT algorithms if you want to compare your results with earlier data. The functions ChnFFT1, ChnFFT2, and ChnInverseFFT including the related dialog boxes FFT with one time signal, FFT with two time signals, and Inverse FFT are affected by these changes.
Otmar D. Foehner
Business Development Manager
DIAdem and Test Data Management
National Instruments
Austin, TX - USA
"For an optimist the glass is half full, for a pessimist it's half empty, and for an engineer is twice bigger than necessary."
Attachments:
FFT_Use_in_DIAdem.pdf ‏682 KB

Fan Error on HP desktop

hi there guys,
i got a hp: p6203w desktop computer with the stock; Sunon KD1209PTS2 on board as a case fan.
I recently switched it with a Noiseblocker MS-81 quiet fan and got the cpu fan failure on startup.
Now whats weird is when i check my speeds with speedfan software is that, with my original fan the software say Fan2 : 1000 RPM
now when i start windows 7 (after i pressed F2 when failure pops up) and check my speeds with the new fan , the software say Fan2: 0 RPM
whats remarkable is that the new fan is actually turning , when i checked my computer open-cased, not very fast but its slowly turning, while the software said it doesn't
So whats this saying for me is that the computer didn't recognized the fan in the first place at starting up the computer !
Do you guys know if this has something to do with a RPM check at startup ? Or is it another difference in specifications of the two different fans ?
Its no possibility for me to check out my bios, because i already checked and i'm not blessed with a cool n quiet function or other fan settings
Maybe the new Noiseblocker fan is just not turning fast enough for the computer to recognize it ?
Please help me out here i got stuck !
Best regards
Willie

willibrord87 wrote:
all my fans are 3pin also the new one but the new Noiseblocker has a 3pin (tacho) connector?
maybe this has something to do with this problem ?
You say it has a 3-pin tacho connector?
Speedfan may not be reading the tachometer signal with the Noiseblocker fan because it is is faulty. Normally changing the fan is quite straightforward.
If the fan is running,you have checked the CPU and motherboard temps and they are within specs, it is really not an issue. It is more of an annoyance if you are willing to tolerate it. You may be able to turn off the warning in the BIOS
What is the CPU that is installed?
The standard is a single three pin connector.
****Please click on Accept As Solution if a suggestion solves your problem. It helps others facing the same problem to find a solution easily****
2015 Microsoft MVP - Windows Experience Consumer

How to measure and log frequency with fieldpoint CTR

Hi,
I am developing a data acquistion and control system for an engine dynamometer using the fieldpoint modules and Labview. One of the most important signals is the engine speed, measured in RPM. The RPM signal is a 0-12V pulse where one pulse equals one revolution of the engine. As well as being an important piece of data for later analysis, engine RPM will also be in the input into a PID controller, so the signal must be both accurate and have a high measurement frequency.
Currently I am using the FP-CTR500 modules to measure the frequency of the signal. I am already aware of the included frequency measurement VI example, as well as the one posted before for low frequency measurements, and I have gotten both to work with my setup. I would be using the low frequency VI becuase the max frequency measurement would be in the 200Hz range.
The first problem I am having is with the structure of the VI and how the data is output. The case structure in the VI activates when the counter is read and resets the counter, then switches to the next case. I would like the RPM number to output out of the case structure into a write_to_file VI and PID controller input. The problem is that when the case switches, the counter is reset to 0, which will be recorded in the written file.
This is some example output data (RPM):
1232
0
2321
0
2400
0
2521
0
The data is being written correctly, but of course I can't have 0 readings when the case structure changes. This would be especially problematic when input into a controller VI.
The next problem I am having is with sampling rate. If I were to use the low frequency measurement VI, the sampling rate of RPM would be variable based upon the the speed of the signal. Or, the original frequency measurement VI has an adjustable sampling rate. Of course, in my system there are a number of other signals that need to be recorded at the same time. I have found that as I am collecting data, the "write to file frequency" is entirely dependent on the read frequency of the frequency measurement. Therefore, if I had set the read frequency VI to read at 1 Hz, data will be recorded only every 2Hz. Ideally I would like an overall measurement frequency of all channels (mix of analog and digital) to read between 20-50Hz, but if I am limited by the frequency measurement.
Any ideas on how to solve this problem, either through Fieldpoint or Labview?
I can post my VI if this help.
Thanks,
Huang

Thanks for your reply.
I should probably describe my current setup before I go into anymore details with the problem. As for my specific setup, I am using an FP-1000 connected with an AIO600, AI110, CTR500, and TC120 all running through the RS232 line to a desktop running labview 8. The actual counter module is reading a tachometer signal output from a separate engine controller. THe output is a 0-12V ON 50% duty cycle signal. As for data logging, i am simply using a "write to measurement file" Express VI. I have a while structure which holds all of the express VIs which access the fieldpoint IO, and these are all routed to the "write to" VI.
As for the specifics of the data logging problem, as I said, when I set the count frequency of the "Fieldpoint Frequency Measurement" VI to 1Hz, (which means the VI calls the case structure at 2Hz), the "write to measurment file" VI is called at the same rate (2Hz). Which means that the overall logging rate of the VI is only 2Hz. Is there someway to decouple this?
I was able to solve the problem of calling the frequency variable from the case structure by using a local variable which is called outside the case structure.
And now I have been having a lot of problems with reading the actual frequency from my engine controller. THe actual signal will only range from 0 to around 200Hz. I noticed, by comparing the actual signal to what was being read in my labview program, that after around 80Hz the signal increases by around 1.5times more than the actual signal. ie. Actual signal = 100hz, Read Signal = 150Hz. After trying to figure out what was the problem, I decided to change the Noise Filter settings to 200Hz. It actually worked for all the frequency ranges up to around 150Hz but after that the filter attenuates the signal to the point where the actual signal is 160Hz, but is being read at 100Hz. My question is if there is a way to change the actual filter setting outside of the 2 given setpoints (200hz and 40khz) or if you have any other suggestions on how to fix this problem? I was thinking of creating a noise filter input in MAX so that i could play with the values in Labview, but am i only limited to those two filters?
Thanks again for your help,
Huang

Synchronizing two counter frequency inputs with multiple analog inputs

Hello all,
I'm fairly new to LabVIEW and I'm trying to collect data from multiple sources with synchronized timing on the acquisition but I'm having trouble figuring it out. My problem is that I've got two counter frequency inputs, one optical tachometer reading one pulse per revolution, and a max machinery flow meter with a k factor of 12000. I can't seem to figure out how to sync the timing with my multiple analog inputs. I've been attempting to get the tachometer to sync with the analog inputs first by following the example linked here. (https://decibel.ni.com/content/docs/DOC-10785) So far each time I run it I either get a timeout error on the DAQmx read or a "Multiple sample clock pulses were detected" error (see attached image). It seems if I slow the sampling rate way down to say 10 hz and ensure that the tachometer signal is over 800-1000 RPM (13-17 Hz) before starting the VI then the program will run without errors until the RPM drops below that threshold then the "Multiple sample clock pulses" error occurs. The code is attached below.
Does anyone know of a more effective way of syncing counter frequency inputs with analog inputs? I'd like to have a VI that can show 0 RPM (and eventually 0 flow as well, but I think I need to figure out the timing of one counter before I add another as it seems I can't have two counters in the same task). Any help on this would be greatly appreciated.
LabVIEW version 13.0
cDAQ-9178 Chassis with NI 9401 for the two counter inputs and NI 9205 for the analog inputs.
Thanks!
Richard
Solved!
Go to Solution.
Attachments:
SimpleDAQ.vi ‏44 KB
LV_Error.JPG ‏31 KB

Maybe third times the charm?
So I've finally got a good handle on why the VI is having problems at low RPM though I'm somewhat embarassed how long it took me to do that
Because I have the counter time synced to my Analog input task if it doesn't see at least two pulses between the two clock pulses set by the analog input task I get the -201314 "Multiple sample clock pulses" error. This seems fine at first as it just sets a minimum RPM that I can measure and it's well below the area I'm interested in so no problems there. I tried a simple error handler that would clear the error when it happend assuming the loop would keep iterating until the RPM went above that minimum at which point I would get a signal again. This is not the case, the read function just continues to spit out the -201314 error even after the RPM is back in the readable range. So then I tried adding two case structures so that when the error occured it would stop the task, clear the error, and then start the task again on the next loop iteration (Code Attached). This also doesn't work as the error shows up again on the stop task and then AGAIN on the start task on the next loop iteration. It seems this error is not actually being cleared and once it happens it stays with the task regardless of what the error cluster is carrying.
Anyone have any ideas? The only solution I can think of is to just clear all tasks and recreate them each loop iteration until the RPM is readable again but that strikes me as a horribly clunky solution.
Richard
Attachments:
SimpleDAQ_1_Start Stop.vi ‏48 KB

Stop and start counter set to frequency read

Original question posted in the counter forum but no response so hope its ok to try here?
I am using a 6024E interface to operate a PID loop that keeps the RPM stable of a servomotor but having problems when attempting to read frequency at the same time from a flow-meter.
Basically the operation of the system is as follows;-
User sets an RPM demand, say 5000RPM, an analog signal is sent out to the motor controller and motor runs up to this value after a brief delay. The feedback from the motor is from its shaft encoder which gives 1000 PPR, after signal conditioning in hardware this signal is applied to the gate of timer 0 and after scaling applied to a PID loop. The PID loop is quite stable and responds well to operator demands.
However the first problem was noticed when the RPM demand was taken to zero and an attempt to halt the program was made. There was a delay in shutting down that was roughly equiv to the time out value which was set on the DAQMX read Vi.
Things became much worse when a further loop was added to read a flowmeters frequency output (approx 50 to 300Hz max, counter 1) that varied with the servo motors RPM demand. This additional routine has almost stopped the whole program initially starting as it appears that counter channel 1 is waiting for an input before letting the rest of the program run.
I have attached the part of the program that I am using now to read the frequency of the flow meter, similar routine also being used to monitor the RPM of the servo motor.
Basically when the operator increases the RPM demand and reaches a demand of 10RPM a compare function places an output line, which is connected to the input OPR1/PFI7 (see attached vi ) to logic 1. This then triggers the counter to start reading the RPM of the motor. A similar method is used for the flowmeter but in this instance it does not try to read the flow until the motor has reached 3000RPM as the flow being measured is very low and below 3000RPM it is only about 2cc/min = 40Hz.
Problem occurs though when the RPM is reduced to zero and the flow/RPM stops. If the RPM demand is increased again the motor sometimes will not respond and suffers delay. Removing the loop for the flowmeter cures this problem. Seperate loops are used for the flowmeter, motor RPM and PID loop that controls the motor RPM.
The problem, as I see it, is that I need to be able to stop the counter for the flowmeter aquiring data when it falls below a certain value but be able to restart it again when the the flow increases?
Also is there any way I could sync the analog output signal (motor RPM demand) to the counter freq read signal (motor encoder feedback)? I found examples in the help files for this but using 'count edges' not frequency or period mode.
Thanks John
Labview Version 8.5
Labview Version 8.6
Labview Version 2013
Attachments:
arm triggerver1.vi ‏38 KB

Hello,
First of all thanks for posting on our forum.
I may be lazy but I think your question is very long and not very clear... Next time try to be more precise and to post shorter messages, this is just an advise, but short questions often get quick answers.
now let's talk about your problem, the first thin I'll say is why don't you use NI-Motion hardware, that would be really appropriate to you application, then if you can't (which I understand) you should really use Real-time programming, when you're using a PID, real time is really advised.
My only question will be : What is the problem? can you be a little bit clearer? what can we do for you?
I'm sorry but I'll really be glad to help you but so far I did not understand.
Regards
Richard Keromen
National Instruments France
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Need help for encoder count program !!!!!!!!!

I am a new labview user.
And i am trying to complete a project for my course.
For a quick background on what I am working with, I am using a NI PCI-73566-Axis Stepper/Servo Motion Controller for PCI, NI UMI-7764 Series, NI USB-6009 and a IDEC SC1B Rotary Encoder.
I am try to design a encoder count program and a new program to convert the encoder signal to RPM.
But I just don't know where should I start? How can I get the same block diagram like P11 in the attach file?
Please check more detail from the attach file.
Attachments:
P11.jpg ‏127 KB
P8.jpg ‏149 KB
P15.jpg ‏141 KB

Hello,
The two objects on the block diagram are DAQ Assistants and can be found under Functions»Measurement I/O»NI-DAQmx. From what I can gather, this is acquirign signals that you should have connected to the USB-6009.
-Zach
Certified LabVIEW Developer

Samplerate problem using Analog In and Counter In from a NI 6259 USB. "Counter timeout" setting in DAQmx?!

Hello,
I got a fundamental problem with the correlation of the timer settings of the DAQmx driver in DIAdem DAQ. I dont know where the problem is located exactly but maybe someone can help me if I explain what happens:
In my configuration I use some analog inputs from a USB 6259 with 20kHz samplerate and two counter inputs for frequency measuring via DAQmx in DIAdem DAQ.
There has to be an extra DAQin block for the analog inputs and the counter inputs with also an extra "Clock"-block for each of them. The clock of the analog inputs runs with 20kHz hardware clock and the other one with 10Hz software clock because the hardware clock mode is not allowed or supported.
My problem is the display refresh rate in VIEW. If the counter signal has no input (because the measured system is not active) the display seems to wait for any input and doesnt refresh the analog values on screen. If the system is active and a rectangle signal is seen by the counter in, the display refresh rate raises and the frequency value is displayed more or less accurate. Has that something to do with the counter timeout setting in the DAQin driver options block (marked in the attached image)? If i decrease the timeout, the display refresh rate gets better but not as good as without using the counter inputs in my DAQ diagram. I think the counter input is not as easy to handle as the usual analog inputs... I only want to see the measured frequency on the display during the measurement without getting any influence on the analog input channels and their displaying.
The other problem is the display and the measurement of the frequency itself. If i check the function of the counter input in the Meas. & Automation Explorer the frequency is display correct without any dropouts or something like that. The signal I measure in DIAdem on the other side looks quite bad because there are spikes of some MHz and even more although the measured range is between 20 and 80Hz!
Has anybody made similar experiences?
Regards
S. Zimmer
Attachments:
probs.png ‏112 KB

Hi there,
it seems that german is your mothertongue, so I'll reply on german.
Digitale Eingänge müssen Software getaktet werden, da nur analoge Eingänge Hardware-Takt Unterstützung haben!
Sie können den Hardware-Takt nur mit analogen Eingängen einsetzen, die, von einem Timer gesteuert, gepuffert Werte einlesen können. Digitale Größen verarbeitet der Hardware-Takt nicht.
Mit dem Hardware-Takt erreichen Sie sehr hohe Abtastraten. DIAdem überträgt die gewünschte Rate und die Kanalliste auf die Karte und startet die Messung. Die Hardware erfasst die Daten selbstständig und sammelt die Daten. Der PC ist nur für den Abtransport und die Weiterverarbeitung verantwortlich.[...]
Da digitale Signale nicht im Hardware-Takt erfasst werden können, müssen diese Signale parallel in Software-Takten ermittelt werden. Dies kann zu zeitlichen Verschiebungen führen, weil sowohl beim Start der Messung als auch während der Messung keine Synchronisierung der Timer im PC und im Messgerät erfolgen kann. Da zwei Timer nie ganz genau gleichzeitig gestartet werden und auch nie ganz genau gleich schnell laufen, stimmen die Zeiten in den Zeitkanälen nach der Messung nicht genau überein. Üblicherweise betragen die Abweichungen einige Millisekunden.[...]
Weiters hab ich mal n Versuchsaufbau für die Frequenzmessung gemacht. Ich konnte problemlos Frequenzen messen...
Am besten du schilderst kurz den Aufbau deiner Messung, was du messen möchtest und wie du den Max konfiguriert hast.
Mfg Markus

Msi R7950 3Gb 384-bit OC edition Noise Level?

Hi, I received my new pc yesterday and spent last night installing all the drivers,OS, etc.
My GPU idles at 36C on Summers day and about 68 when playing Games like MoH Warfighter or during a benchmark test. The problem however is that i'm not quite sure about the fan speeds. It runs at about 59% (all acceptable),but the RPM is 4600 and that is really loud. My card is running on factory default settings with the Graphics OverDrive set at the default GPU Clock @960Mhz and Memory clock at 1250.
Can anyone just confirm with me that these specs are normal, I'm actually only worried about the fan RPM because it's as loud as my 9600GT at 95% fan speed

I would just like to add that at 43% fan speed idling the tachometer reads an RPM of 1844 and everything is real quiet . Also when I manually adjust the fan speed to say 60% the RPM only increases to 3042 compared to that 4650 when it's on auto in games, but that is while idling and not in a high-performance game or benchmark.

Digital Tach on an FPGA

I am trying to implement a simple digital tach onto a machine. Its a proximity switch and a disk with several holes. I want to verify the disk is rotating and don't care (at least for the moment) how fast. I'm using a digital input on my 9074 FPGA and simply want to check for the digital transition over a set time period. Can someone please show me where I can find a sample vi that will accomplish this? Or does someone have a vi they could share?
Thanks
Solved!
Go to Solution.

Hello,
Here is a DevZone with a link to example code for decoding Tachometer signals. Its using Analog Signals, but it shouldn't be hard to change it from analog signals to digital signals. Someone else on the forums may have implemented this with digital however.
Also check out the following Discussion forum.
Regards,
Andrew
Message Edited by Andrew_E on 07-17-2009 11:50 AM
National Instruments
RIO Embedded Hardware PSE
CompactRIO Developers Guide

How many revolutions of data are required for order analysis?

Hello,
I have a requirement to collect, process, and save data for several hours at a user specified sampling interval. I suspect that I will need to use the speed of the motor to determine how many revolutions of data I am collecting.
Is there a minimum number of revolutions of data required for order analysis?
Thanks,
Chris

HI Chris,
Thank you for posting on the National Instruments forum. To determine how many revolutions of data that you are collecting, you will need to use the tachometer signal that is coming off of your motor and is defined as pulses per revolutions. With this, the absolute minimum that you need is two pulses to figure out how fast your motor is spinning. With only two pulses, however, it will be very hard to determine the order information.
I think this KB will help you in figuring out what Window Length you need when doing order analysis.
How to Select the Window Length When Extracting Orders with Order Analysis
Please let me know if the knowledge base article does not contain the information that you are looking for.
Thank You,
Nick F.
Applications Engineer

Tachometer signal to RPM in DIADEM

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