Displaying analog signal in case of glitch

I want to display the signal in the analog format
Since there is a glitch in the first few ns the actual graph gets suppressed to represent the glitch in the available range.
Is there a way so that it would display the required waveform correctly.

I am using suse linux and i am not able to enter anything in those boxes . I have changed the off scale to clip. recently i go the window without glitch and do reset zoom y . But when i change the window or zoom out the condition gets reset. As you can see in the images i get the the required graph but only part of it and after zooming out the glitches again start to dominate.i do not want to seet that part.my actual signal lies in low resolution.

Similar Messages

Displaying analog signals

Dear Labview Users
I am using the AI read.vi module to display four analog signals. I can do it simultaneously in one single display, however I need to have them displayed independently in four displays.
I have tried to use transposed array, reshape array, etc, etc but with no much luck.
Thanks for your help.
David

David,
Have you looked at the Waveform Operations (LV 6) - (Functions > Waveform > Waveform Operations palette). There is a VI called Index Waveform Array VI for selecting a waveform out of an array of waveforms. If this isn't just right, there are many others which might fit your situations.
Good luck with it, Doug

Analog Signal to Digital a Primer

Many users have analog material sitting around, and they would like to get it into digital form, so that it can be edited. As this material is below SD (Standard Definition) quality, I will address the methods for digitizing it, so that it can be best edited in a DV Project. The output can be a DVD-Video, or other format, depending on what one wishes.
The process of getting this analog material into a digital form, is referred to as Capturing, and it is digitizing the analog material and writing it to a file, that can be edited.
One will need some method of getting the analog signals into digital form, and for connecting the analog output from their analog playback device to the computer. Though the analog signal could come from all sorts of devices, I’ll use a VHS tape deck in this example.
Since a VHS tape deck does not have an A-D (Analog to Digital) processor, and also does not have a a digital signal Out, one needs something in between it, and the computer. That “something” serves two needs: mechanical connection of cables and the ability to convert the analog to digital for use in an NLE (Non Linear Editor). That “something” can be a digital video camera with pass-through capabilities, a device, called a “bridge,” or a capture card inserted into a bus slot in the computer. All three have pluses and minuses.
The first two methods rely on one having a FireWire connection on the computer and will use the Capture module in the NLE software.
The digital video camera route is good, as one already owns it. Having one with pass-through capabilities is getting more difficult. The camera also has to have FireWire (FW, IEEE-1394a, or iLink) output, and the computer must have a matching connection.
An A-D bridge will do the same thing: allow one to connect the analog cables to one end/side, process the analog signals to digital and then output via FW to the computer. There are various such bridges available and two of the most often recommended makes/models are: the ADS-Pryo, and theCanopus/Grass Valley ADVC-110. Products, like the Dazzle lineup, just do not seem to work, or work well. I would avoid such.
A dedicated capture card performs the same task, with one exception. The card will mount into an empty PCI slot on the MoBo, and have inputs for the analog cables. The card will have chips on it, to digitize the analog signals and feed these to the computer via the PCI slot. These do not connect via FW, but have one drawback: they must, in virtually every instance, use additional software to do the actual Capture, as most NLE’s cannot directly see and work with them. Some of the included software Capture programs are better, than others. One common issue with many of these cards is a loss of sync, between the Audio and the Video. This is usually static OOS (Out Of Sync), in that it is usually off by a fixed number of frames, and does not drift over time. This can be fixed in the NLE, but is extra work. This ARTICLE will give you tips on correcting OOS.
Now, we are ready to begin the Capture, as our equipment and cables are all ready to go. We have a big decision in front of us - what format/CODEC do we use to Capture our digital files? Since we are doing an SD Project with non-HD (High Def) material, there is one fine choice: DV-AVI Type II w/ 48KHz 16-bit PCM/WAV Audio, using the DV/DVC CODEC. These files will be approximately 13GB / hour of Duration. Storage will need to be considered. These files are also I-frame, meaning that each “Frame” is rendered and available, so that frame-accurate editing is possible. The NLE will not need to do any processing, or conversion of these files, as even the Audio is ready for DVD-Video. Note: there will still be Conforming and the generation of PEK (Waveform Display) files, but the NLE will be able to do this quickly and efficiently.
Using AVI Uncompressed will get you nothing that you can see, other than larger files. Do NOT use any compressed format/CODEC, like MPEG-2, WMV, MOV, etc., as these will loose data from an already inferior source, and will then need conversion to be used, either with a stand-alone conversion program, or internally by the NLE. You loose quality and then have more work to be done. Do not let the temptation of smaller files lure you into using anything but DV-AVI Type II, and just accommodate the larger file sizes.
With the file format/CODEC decision made, the cables and devices hooked up, we’re ready to start the Capture. The exact operation will depend on what our equipment choice has been. See above for talk about additional Capture software, if one uses a capture card. Otherwise, we should be able to use the Capture module of our NLE. The first issue is that we will NOT have Device Control, as we would with a Capture from a miniDV tape-based digital camera, where we can control the mechanical aspects of the camera, during this process. As our VHS deck is hooked up to the A-D bridge, or digital camera w/ pass-through, via analog cables, our control signals cannot be sent to it. One would cue up the tape in the VHS deck, and then choose Record/Capture in the NLE’s Capture module, starting the Capture. Instantly, they would hit Play on the VHS deck, or via that deck’s remote control. This is easier the second time that one does it. I sit with the mouse in my right hand, poised over the Record/Capture button, and the VHS deck’s remote in my left hand, finger hovering over Play. It’s then a 1 - 2 push, and all starts. One can stop the Capture, if an unwanted section of tape comes up. The Capture module of the NLE will direct us on how to proceed from there, should more Captures be wanted. Some will just start up at a later point, and write an additional file for that portion of the tape, but some might require that one basically sets up a new Capture session One should investigate just what their NLE will require for doing multiple Capture sessions from one VHS tape.
When done, one closes the Capture module, and then navigates to the location that these DV-AVI Type II files have been stored in, and Imports them into the Project. This differs slightly from doing the Capture from a miniDV tape camera, as those Captured files are already in the Project.
Edit away, and Export/Share to the necessary output settings, file type and CODEC.
What about those VHS - DVD decks, the ones that will burn a DVD directly from the VHS tape? They seem so simple to use, and for the most part are. However, those DVD-Video discs, contain pretty heavily-compressed MPEG-2 AV streams. These MPEG-2's, besides being compressed, are in aGOP structure and are muxed (Multiplexed into one file with both a Video & Audio stream), plus there is often some Menus and navigation in the first VOB, the main container components of a DVD-Video. Many NLE’s can Import the VOB’s, and basically rip the MPEG-2 out of them, but that first VOB can be highly problematic, due to the way that most of those decks do the Menus and navigation. It is seldom 100% DVD-compliant by the DVD-specs. This can be a major problem. This ARTICLE will give you some background and tips on DVD VOB's.
Those dual-decks are good for doing one thing, regarding the DVD’s that they produce - provide one with an archival DVD-Video of the VHS tape, and not to be edited. However, the VHS side of these works well with an A-D bridge, just like a pure VHS deck does. I would strongly recommend that one does NOT use the DVD-Video portion of these, if editing will be desired. They cause many more problems, than they solve - just use them for an “archive” copy of the tape to a DVD-Video, for playback on a computer via DVD software or a set-top player, hooked to a TV.
What about film? Well, film is obviously analog, and one needs to digitize this to edit on the computer. The process of this digitizing is referred to as telecineing the film. While one can buy equipment to do this, it is expensive, and involves a lot of setup and testing to get the job done. There are many service bureaus, that offer telecining. Some are better than others. The main considerations are: care in handling of fragile film, how the telecining is done, i.e. frame by frame w/ a liquid gate, or just by straight projection, and then output format for the digitized files. Some of these services will offer a DVD-Video disc. Do not be tempted to do this. See above. Others will offer to write these digitized files to a miniDV tape, and this is just fine. One does then need a miniDV camera, or miniDV tape deck, to then do the Capture from, but the quality and editability will be preserved. The final delivery format would be to put these DV-AVI Type II files onto an external HDD. This saves one from having to do the Capture from miniDV tape, having to have a miniDV camera, or miniDV deck, and only Importing of those files would be required to get them into the Project. Many of these service bureaus will either sell you the external, or use one provided to them. Check out specifications for things like format of the external. FAT-32 will limit the file sizes to ~ 4GB max, and NTSF will have no such limitations. However, if the service bureau is on Mac, and you’re on the PC, their Mac’s can ONLY see FAT-32 HDD’s. Talk this over with the service bureau first, so that there are no surprises later on.
Hope that this helps,
Hunt
PS - also see this FAQ Entry for more detail.

the_wine_snob wrote:
Products, like the Dazzle lineup, just do not seem to work, or work well. I would avoid such.
Although I now have a Canopus ADVC300 I previously used a Magix 'Movies on DVD' USB device. I found the results from this to be particularly good and, to my ageing eyes, I see very little quality difference.
I think this is because Magix use their proprietary high quality codec (from their Pro products) to capture the footage. Like DV-AVI it runs around 10GB+ per hour. This can then, very simply, be exported to DV-AVI Type 2 for use in PRE. Note that there are some sound synchronisation issues with the 'out of the box' settings - but the fix is quick and I posted details to the Magix forum.
Would I revert if I could return my ADVC300 bridge? Probably not - the firewire connection and the PC seeing the box as a camcorder adds to ease of use. In fact I am pleased to have both. There are some things Magix does better than PRE7 (batch exporting each scene as an individual DV-AVI file being just one) and it has smart-rendering which is handy for quick clip splitting/exporting.
Cheers,
Neale
Insanity is hereditary, you get it from your children

How do I set a threshold from an analog signal (4-20ma) coming in on a cfp AI 110, to trigger an alarm on my UI?

I have the alarm set, indicator set, just need a digital trigger from an analog input. I realize I could use an external switch into a digital input, but would rather use what we have. We are using this analog signal for other purposes as well. This application is for controlling a machine. Thanks.....

Hi Bob,
The way you have your Case structure setup now is that the “7” case will only get executed if the value from the wire is exactly 7. This same applies to the “8”. Also, there is no default case, so if value does not match any of the cases then your indicator will not change.
You indicated earlier that you need the indicator to be ON when the value is below 7mA and OFF when above 7mA. You will want some like this:
Alternatively could just use the Not function inside the Boolean palette to achieve the same functionality without the case structure.
You will want to check out the LabVIEW Training Page.
Message Edited by DiscoBall on 03-27-2009 12:12 PM
Message Edited by DiscoBall on 03-27-2009 12:13 PM
Joshua B.
National Instruments
NI Services
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Attachments:
compare.jpg ‏27 KB

Problem when combinning PWM signal and Analog signal TOGETHER!

Hello everybody,
first of all i have DAQmx 6212, and i need to run a small water pump (9V-16V) which needs to be driven by a PWM signal; also i have a motor (5V-13V) for a water valve that needs to be driven by a analog signal and it has a built in a force feedback potentiometer, i connected on the extremeties of this potentiometer +5V from the DAQmx and used the output voltage from the third extremety as a diagnose value for knowing the position of the motor.
my VI shows:
1. is a normal Counter output to create my PWMout signal.
2. is an analog input i use it as a PWMin to the LabVIEW to diagnose what is happenning in my water pump through the duty cycle and the frequency.
3. is an analog input from the third extremety of the potentiometer.
4. is an analog output which i have used as a power supply for the motor valve and i have used an AC/DC amplifier to aplify the signal from the DAQmx and drive the motor, between (3. and 4.) i have made a feedback with some calculations i had a P-controller to know the actual position of the motor valve.
My Problem:
when putting 1. and 2. in the same VI alone, i am getting a clean PWM in/out with no problems mentioned;
also when putting 3. and 4. in the same VI alone i can control the motor valve without any problems;
but when i put all these 4 together as found in the attached VI, i have a problem that the motor valve is running continously without stopping even if i change the valve position between 0 and 100 %, i should mention that i am seeing a normal PWM out/in signal on my oscilloscope, one other thing that if i delete one of (1. or 2.) and run the VI the motor valve is working fine without any problems.
so this my problem, if you can think of any solution please let me know.
thanks in advance for your help.
Regards,
Alosh
Solved!
Go to Solution.
Attachments:
pwm.out.in.analog.out.in.vi ‏45 KB

Dear nathand thanks for your reply,
i have ran the vi again and i am have error no 50103 from the (AI, number 3. ) but it is not displaying the error message, the VI keeps running without any error notification.
adding to that, i have tested the VI again today by placing (1. and 2.for the PWM inout) together in one VI and (3. and 4.for the motor valve) in another VI and ran them one after the other, i had another problem. if i turn the motor valve vi, the motor will run smoothly but in the pwm vi i will have a problem in which the AI did not read any value. also doing this vice versa by running the pwm vi first it will work perfect but the motor vi will have problem in reading the measured voltage in AI during this the motor will keep on running without stopping.
so i think now the problem is in AI (2. and 3.) readings they are interfering on each other but i am not discovering where is my problem...
Q: does the AI's seems well build or i can do it in an another way so to get over the interfering?
Regards,
Alosh

How to convert a analog signal to digital signal

Hello,
How to convert an analog signal into digital signal such that every sample of analog signal corresponding to 1.2V will be represented as '1' in digital signal and other samples of analog signal(that are not 1.2v) will be represented(converted) as '0' in digital signal.
And how to display both wavefroms or signals in graph indicators.
Thanks.
Solved!
Go to Solution.

If you have 1000 samples, and you want to convert to digital, you are going to get 1000 digital values. Attached is what I mean.
Unofficial Forum Rules and Guidelines - Hooovahh - LabVIEW Overlord
If 10 out of 10 experts in any field say something is bad, you should probably take their opinion seriously.
Attachments:
Analog_to_Digital Hooovahh Edit.vi ‏52 KB

Is there a VI availible that will allow one to interact with an analog signal

Hello all,
I am new to the sight and look forward to participating. I have a project that I’m working on and I would like to ask for your thoughts and direction if you’re willing. I have a few weeks left before completing an electronics program degree and Labview is one of the classes. The project I have chosen is to illustrate the differences between a micro controlled system and Labview controlled environment. I will be acquiring a signal through a ultra sonic distance sensor. The analog signal will be produced after which acquired through a SCB – 68 connector block and converted using the pci-mio-16E. The sensor operates at 40 kHz emitting a 5v pulse (burst) then falling to gnd for a short period followed by a 5v rise and staying high for a period of time waiting for the return of the frequency. This time period represents 3 inches to 27 ft in distance. I would like to interact with this signal through the distance period (portion) and output a string displaying a numeric value of the distance on the front panel obtained from an array built from different periods of the signal. I am not clear on what Labview function offers this type of control. I am hopeful in utilizing a vi or some type of trigger that allows me to build an array produced by some math functions. Any help would be appreciated.
Thank you, dhitch

First thank you for your response, I will have an opportunity to make a capture tomorrow in class. I believe I have run across the waveform measurement VI in my searches and am sure it’s a very good choice. The trigger VI you suggest, going by the name, should be my ticket. Would you imagine a delay or decreasing time after the capture, allowing the trigger VI time to respond to an output configuration be required?
If I remember correctly the sampling rate capabilities are 500K samples/ second with 12 bits of resolution and as I say that it seems some of the capabilities rely on the processing speed of the computer. I guess I will kick the tires tomorrow hey. There are 2 class periods remaining to finish our projects @ 2 hrs / class and my anxiety is a bit high. Wish me luck and thank you so much.
dhitch

Filtering Analog Signals

I am currently using a PXI 6025E board to read an analog signal from a weigh station. The items that are being weighed are in motion so the signal contains some vibration from the item being in motion as it crosses the scale. I would like to be able to filter the analog signal so that I just get the pure weight and not the noise from the vibration. What is the best way to filter the signal using LabView?

Another method is the store a number of results and calculate the
average of these points.
Do sample fast to get more data and you will get a better result.
The method with the best results depends on the noise expected, on its
spectrum and amplitude distribution.
Median is fine if you have a lot of good data and a few wrong ones far
away from the 'real' result..
AVG and Lowpass is fine for symetrical noise.
DC / AC is fine in the same case, but the parameters cannot be chosen by
yourself.
Good Luck
Urs Bögli
preston johnson schrieb:
>One method is to use a "median filter" this is a statistical median
>of the data you have collected over a brief period of time.
>Presumably, you will have a good number of cycles from the vibratory
>motion. Use th
e statistical function for median. This will sort the
>data from most to least and produce a number in the middle of the
>list.
>
>A second method is to use a low-pass filter to filter all data above
>say 1hz.
>
>A thid method is to use the DC and RMS function and take the DC output
>of the function.
>
>Try all three to see which produces the best result.
>
>Sincerely,
>
>Preston Johnson
>
>

Time Coded Analog SIgnal

Hello,
I am relatively new to LabVIEW. I am working with a device which sends out an analog signal (4-20mA) that is time coded with 6 pulses. I need to program LabVIEW to read the values of the 6 pulses, or really 5 because the first pulse is an identifier, see the attached pdf file.
The signal starts with a 20mA signal for 2 sec; this is the identifier signal. There is a pause for 2 sec and then the first of five signals, which are transmitted for 2 sec each with a 2 sec pause. At the end of the sixth signal there is a 30 sec pause (4mA). The identifier pulse will always be 20mA but the five other signals can vary in amplitude. I need assistance in reading these five signals; from here I can scale the mA value to what I want.
I am working with LabVIEW 8.2 and I am using an ENET 9219 module. I can acquire the signal graph it, display the value etc and I can also trigger off the first pulse, but the rest is proving to be difficult.
Thanks for your help!
Brian
Attachments:
analog signal.pdf ‏37 KB

To get an idea of what the signal values are take a look at the spreadsheet and the short code to generate the sample data. At the end of the last pause (30Sec) the signal repeats again, starting with the 20mA identifier pulse. This devise is a fluid monitoring sensor for hydraulic oil. The idea is to have this continuously read data and display all 5 signal values. Display does not need to be instant, as with temperature and or pressure readings.
I tried to use the Get Waveform Subset, but experienced an error. I was trying, as a simple test, to see if I could manually trigger the start of the recording when the 20mA pulse came up. When I trigger how do I get the subset to start from 0 on the time line? If I could start from 0 every time I could read from the approporate time (t) to read the value at y.
Thanks.Brian
Attachments:
SampleData.xls ‏29 KB
short code1.pdf ‏36 KB

How can analog signals are measured every several counters from Quadrature Encoder using USB-6221

how can I sample analog signals every counters from quadrature encoder using usb-6621?

There is a well documented example of what you are trying to do at :
http://zone.ni.com/devzone/explprog.nsf/webmain/DD85F07A7CA99F8F862568690062DE54?opendocument
Don't be afraid because of the BNC-2120. It is just used in this example to simulate the pulses from a device. So it is not needed in your case. Obviously, you will need to change the number of increments/rev according to your encoder to get correct RPM values.

Unclearity about analog signals

Greetings,
I am trying to create a small DAQ system that digitalizes a analog signal and displays the waveform and spectral analysis. I know that the analog waveform component receives and array to plot the waveform. However I am having doubts about how many samples I need to collect to create the exact graphs that is annexed to this post.
Could anyone give me some help please?
Thanks
Attachments:
InverterWaveform.PNG ‏8 KB
SpectralInverter.PNG ‏8 KB

Recently I tried to made this program to aquire the analog data from a serial port based device. I am trying to use the waveform graph from the right in my program instead of the graph from the left.
I do know that I need to create an array to store the aquired elements and connect to the wave form graph.
Question is: What is the correct way to program that?
My serial device is programmed to receive an character and return a 0-255 number that corresponds to the aquired value.
Message Edited by Borges on 05-13-2009 02:31 PM
Attachments:
sample1.PNG ‏31 KB
sample2.PNG ‏28 KB

Compare two analog signals.

How do I compare an analog signal to another analog signal to see which signal has a higher value? I want to display the result on the front panel using an LED indicator.
Solved!
Go to Solution.

Sorry about the lack of inforomation.
I have photodiode voltage four output signals go into the SCC-68 module. The SCC-68 module is hooked up to the PCI 6224 M DAQ Card.
The signals have almost no noise to them, and I am trying to compare the value (voltage) of two analog inputs to see which value is higher. I want to compare the analog inputs of QPD 1.1 & QPD 1.2 from the VI below.
Attachments:
QPD.vi ‏158 KB

Conditioning of a analog signal

can anybody help me with this one please...
an analog signal should be conditioned before digitizing it or afterwards?
thanks for any help.

Well, once an analog signal is digitized it is no longer analog, so you cannot condition an analog signal when it is already digitized since it does not exist anymore...
But I think the background of your question is more serious. Basically you can simulate all kinds of filters, amplifiers and other signal conditioning circuitry by software. But you cannot avoid errors inherent to digital conversion of analogue signals, such as errors related to aliasing or overdriving an ADC input. So in many cases it is a better approach to do at least the basic analog signal conditioning (i.e. the parameters which probably will not be changed) prior to analog-digital conversion.
A similar question has been discussed recently:
http://forums.ni.com/ni/board/message?board.id=300&message.id=2119

SB X-FI Titanium.. Digital output works but Analog Signal M.I.A.

@SB X-FI Titanium.. Digital output works but Analog Signal M. I.A. Hi Guys,
I recently installed a new hard dri've on my machine after my power supply failed and fried it. After reinstaling Vista 64 and my drivers I noticed that my sound card was not working properly.
In.. control pannel > Sound > Playback I see my soundblaster listed but only the digital out is showing. There are two other icons listed.. one is for "Digital Output Device 2-High Definition Audio Device.. and one for a 3-High Definition Audio Device. I don't remember these being listed when my sound card was working properly before the HD crash.
No icon representing my analog output (Left/Right, Center, and Rear?Speakers)?is displayed. I reinstalled the drivers, updated the drivers, reformatted my HD and started all over again but nothing works.
I made sure that my motherboard sound card is disabled.. I am really stumped.. The sound card used to work quite well.. Has anyone else had this problem and been able to fix it's
Here is my system info:
Motherboard: Gigabyte GA-MA790FXT-UD5P (Realtek Audio Disabled)
Sound Card: Internal Sound Blaster X-FI Titanium
Any advice is much appreciated.

DRe: SB X-FI Titanium.. Digital output works but Analog Signal M. I.A. High definition audio device is what your card is detected as until you install the original CD driver or the Daniel K 2.0 support pack. Then you can update to the newest Creative drivers. I tried to format just like you and thought that I would just download Creative's newest driver and start from there. No Go!!? The newest Creative driver seems to install, but then after reboot like you, I have multimedia audio device.
So take out your CD if you have it, and run the driver setup only. Then using just this driver you can install all of the newer Creative updates. The Creative auto updater is installed along with your original driver and you will see it detect all available updates.
Easiest solution of all,
Try this pack and save yourself a load of hassle........
http://forums.creative.com/t5/Sound-Blaster/SB-X-Fi-Series-Support-Pack-2-0-05-5-2009/td-p/527485
This will install a very proper Creative driver, and applications that will work very very well on your system compared to the CD orignals

How to read and display a signal from my a miccrontroller (MCB1700) onto labview connected via a CAN port on a PXI machine

How do you read and display a signal from my a miccrontroller (MCB1700) onto labview connected via a CAN port on a PXI machine?
I tried using a DAQ Assistant but the CAN port is not included as one of the supported physical channels even though all its drivers are upto date.
Please help..
Thanks.
Solved!
Go to Solution.

Attached herewith is a print screen of what is showing on MAX
The CAN ports are on NI PXI-8461
Hopefully that clarrifies something.
Attachments:
Untitled.png ‏212 KB
Untitled.png ‏212 KB

Displaying analog signal in case of glitch

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