Answer to hardware requiremnts for controlling RH of air
I have an MKS mass flow controller capable of sending flow rate between 0-20 lpm.I have National Instruments labview and use National Instruments field point explorer to control voltage input to the mass flow controller. I also have omega RH sensors capable of sending RH readings in volts, which I read using the .iak files of the field point explorer. Now with all this could you please tell me whats the easiest way to program my application and make the RH sensor and mass flow controller to talk to each other using labview? If you have some code which does this please let me know.
Re: magnetic resonance application based on LabVIEW?
I'm really looking for information about someone who may have already written a program to do what MRI or NMR does. I hate to reinvent the wheel. The Gary Johnson book is helpfull, though Tony Hill
Communicating between computers with GPIB
I've developed a system for automating processing of in-situ vacuum pumps in infrared detector dewars. The systems have been in use for several years and I'm in the middle of an upgrade and I was wondering if I can link the systems together to increase my process throughput. Each system is in a portable rack and rolls up to a vacuum oven where the process takes place. I'm getting pressure readings from an ionization gauge controller using GPIB. I have 4 systems total and I would like to try to link two together so that I can process twice as many units at a time on the same vacuum oven. Currently each system has one GPIB interface and all have the default GPIB address of 0. I know I can give each system's GPIB interface a unique address (0,1,2,3) but I'm not sure how to pass control between systems. Ideally I would hook up both systems to the GPIB, trigger one of the systems to search the GPIB using the Find Listeners VI to determine the other controllers address, and then pass control to one of the systems. I'm assuming I can't do this since both systems are initially controllers and this would screw up communication on the GPIB. These are utilized in a high throughput production environment by unskilled operators, so whatever I do would have to be fairly automatic. These guys can press a button to link the system, but I can't have them configuring the GPIB interface to transition to this mode. Any suggestions?
Re: Using LabView server , is it possible to use the multicast...
Well, it won't be the "web server", because web traffic is TCP and multicast requires a stateless protocol such as UDP. LabVIEW 7 and later include multicast support in the UDP palette ("UDP multicast open") so you should be able to to implement multicast communication with your own code. (I don't understand your title "... send VIs to clients...". Could you clarify?)
Re: Prevent deletion from file dialog
Thanks, we're close but not quite there. Even without selecting 'all files', the user can still see and delete entire folders! -Dave
Re: Prevent deletion from file dialog
Use the "File dialog" from the advanced File IO palette. -- Select "Existing dir" for the mode -- Wire a single space character to the pattern (for example). -- I assume the file name will be programmatically generated. --> The file dialog will only show folders, because the file pattern never matches. (Of course, this is only a soft barrier, because users can still select "all files", highlite a file, then hit delete.)
Re: convolution.vi isn't working properly
It works just fine here. Your VI does not have any default values set, what kind of inputs do you use for testing? Could you tell us in a bit more detail what kind of wrong results you get? (My test example: [1,2]*[1,2]=[1,4,4] as expected).
Re: Missing Mouse Up Bug
Curious, I don't remember seeing this. Could it be you are inadvertently "hammering" the CPU? What is the VI priority setting? (If you e.g. force time-critical, unimportant things will get delayed). Leave it at "normal". Is you code clean, with proper waits inserted or is it just spinning all loops as fast as it can? What else is running on that PC? Is it communicating with DAQ hardware?
Re: Vidas
Hi, Oops! This post seems to have been accidentally posted twice. Please reference the answer in the other post found http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=5065000800E1D5&UCATEGORY_0=_49_%24_6_&UCATEGORY_S=0";>here. Thanks! Kileen C. Applications Engineer National Instruments
Re: Trying to synchronize switching times VERY precisely
The Windoze technical info states that they do not guarantee timing better than 100ms with the system clock. You're right, that generally it's much better than that, but I have seen pauses in my VIs that vary up to 25ms (using a take time before the loop and then check time after the loop). My old Windoze 98 machine varied by as much as 75ms. Yes, NT and XP are better for timing, but there are still no promises. If it's really critical, use hardware (like you said). Rob
Prevent deletion from file dialog
I want to allow the user to interactively select a folder for data logging, but he shouldn't be allowed to delete any existing data files. The path control doesn't have any options to prevent this as I see it. As a possible alternative, I recall seeing a very simple directory-only selection dialog from the Windows API (I think). However, before hunting around for this, I would prefer to find a LabVIEW-native solution. Thanks, -David Moerman
Re: Hallo I am student, I want to ask about Bode plots example...
After looking at the "Bode Plot Wizard.vi", I don't believe there is a limit to the frequency range. The frequency range input has the (0.001 to 100) string here simply to indicate that this is the default setting for the frequency range input used for the bode plot calculation. Please refer to the input description copied from the vi below: Frequency range used for the Bode plot calculation is determined by: 10^(FR-3) to 10^(FR+2) For example: -2: 0.1 to 1 -1: 0.0001 to 10 0: 0.001 to 100 1: 0.01 to 1000 2: 0.1 to 1 Since 0 is the default value for the frequency range input, this is mapped to a frequency range of 0.001 to 100. There is no limit to the frequency allowed. Just note that increasing the frequency input does increase the actual range by a factor of 10. Hope this helps! Kileen Cheng Applications Engineer National Instruments
Re: Ring control behaviour
Pop-up on the ring control and look at the Representation. You'll notice that in some versions of LabVIEW it's an I16 and in others it's a U16. You can change the representation to an I16 and then -1 is a valid number for the ring (instead of just a wrap-around). And, no, I don't know why they changed the default. Rob
Re: LabVIEW as an in-process COM-server
rberger wrote: > I would like to know if LabVIEW is an in-process COM server—an > ActiveX DLL—that implements the IDTExtensibility2 interface. I > am trying to add a COM add-in for a current Microsoft product. LabVIEW is not an in-process COM server. LabVIEW is started as a separate process either as development system or as runtime executable and the Active X interface is out of process to the other application invoking LabVIEW's Active X interface. LabVIEW is also not embeddable into other applications through Active X. Rolf Kalbermatter
Re: Time zones and time stamps
Thanks guys for your feedback... I got a lot of replies that suggest ways I can manipulate the seconds counter in labview to get what i want, which will do the trick. It is not terribly complicated to adjust the seconds in the timestamp control (even accounting for daylight savings, if applicable) and then feed the adjusted value to the format date/time into string function. However, this is IMHO still a workaround (one I intend on using though)... the time stamp control is defined as UTC, so when I poke around with it to get the format function to work the way I want I am in effect going against the definition of the time stamp control. If I started passing this modified time stamp around, things could get *quite* confusing. So to the fellows at NI... isn't it about time we got a little more control over the format date/time into string function? Just adding two inputs, one for whether to use daylight savings and another for which timezone to use would probably cover most needs... and if unwired, there terminals could default to the system settings. That way the new features would not have to break existing code. Just a thought. George At 02:55 PM 5/21/2004, you wrote: The "Get Date/Time in Seconds" function returns a time stamp control that appears to contain the local date and time. Is there a way to convert this to UTC without doing a bunch of crazy tail math / logic? I mean, to do it correctly required a lot of "thinking" to account for daylight savings, leap seconds, and so on... I hope I am overlooking something very trivial. I would prefer to avoid having to make OS calls to query the local time zone, etc if possible. Our system clock is steered by a GPS time server, so the system time is fairly accurate, but for convenience is also in local time. However, we would rather use UTC for creating file names and for timestamps in the files to avoid possible conflicts surrounding the crossover to standard time. (Some of our processes are now 24/7 so this is something we have to consider.) George Gatling Applied Technology Division, SFA Inc. Space Physics Simulation Chamber US Naval Research Laboratory 202-404-5405 (phone) 202-767-3553 (fax) If trees could scream, would we be so cavalier about cutting them down? We might, if they screamed all the time, for no good reason. --Jack Handy George Gatling Applied Technology Division, SFA Inc. Space Physics Simulation Chamber US Naval Research Laboratory 202-404-5405 (phone) 202-767-3553 (fax) If trees could scream, would we be so cavalier about cutting them down? We might, if they screamed all the time, for no good reason. --Jack Handy
Re: Sound Card Question
Hello! To use your Audiophile 2496 sound card with LabVIEW the first thing you are going to need is a driver from the manufacturer. Most manufacturers already have a driver that works with LabVIEW or at least a driver written in C that then you can call from LabVIEW using Call Library Function Nodes. To store the two stereo inputs you can keep using 2D arrays. This time you will have two, one for each stereo input. Another option is to use a 3D array where you will be able to switch between stereo inputs (first dimension), left and right (second dimension), and different samples (third dimension). Regards, Sylvia Vences Applications Engineer National Instruments
Is LabVIEW an in-process COM server?
Hello All: At the moment, I evaluating if LabVIEW is the best tool suitable for my next task. I would like to know if LabVIEW is an in-process COM serveran ActiveX DLLthat implements the IDTExtensibility2 interface. I am trying to add a COM add-in for a current Microsoft product. The MS notes also states the following: Non-modal forms cannot be displayed directly from a COM add-in. If you have non-modal forms, you can have your add-in call an external program (such as a Visual Basic executable) that enables a connection. Does LabVIEW meet these criteria or do I have to program in VB?-(( Robert
Re: Has anyone developed a LabView SPIDF module for a standard DAQ or DIGITAL I/O Board?
Do we have any details for SPDIF ? NI came up with many fast DIO boards this year with superb software Waveform editors. Is it possible to put concept sample on the web if the SPDIF commuunication can be done. I have been asked by yamaha.
Is there any way to read the data from an excel file w/o using a loop structure?
I am retrieving a large amount of data (multiple sheets) from an excel file and would like to extract the entire range without retrieving individual cell values(too slow). I can write an range all at once but cannot read it.
Re: executable problem
...
Re: driver problem
Re: is there a null value in labview?
Drop a numeric control on the panel and type NaN in it. NaN is the Not-a-Number. On the diagram, drop a numeric constant, change its representation to Double (DBL) and type in NaN. For strings there's an empty string constant in the palette. Hope this helps, Khalid
Re: How to convert an array of bits into an array of bytes?
Thank you Rolf. Van
LabVIEW as an in-process COM-server
Hello: At the moment, I evaluating if LabVIEW is the best tool suitable for my next task. I would like to know if LabVIEW is an in-process COM server—an ActiveX DLL—that implements the IDTExtensibility2 interface. I am trying to add a COM add-in for a current Microsoft product. The MS notes also states the following: Non-modal forms cannot be displayed directly from a COM add-in. If you have non-modal forms, you can have your add-in call an external program (such as a Visual Basic executable) that enables a connection. Does LabVIEW meet these criteria or do I have to program in VB?-(( Robert
Re: CONFUSED WITH HEXADECIMAL FORMAT
Hi Rolf, I managed to make it work. I came to a decision to switch the control display to hex and then I typed the command in without H as a suffix and now I am reading values properly but in hex format. I posted new question asking how to convert this format into decimal format which is more convinient for diplay. If you want to check my post it is still unanswered and the tittle is "convert hexadecimal output to decimal (number)". Thanks for your time, Pedja
Re: driver problem
I replaced the visa32 dll, but the error is worse, the program doesn't run at all. When I clicked on it, it immediately said error and the only option was to close it.
Re: driver problem
I replaced the visa32 dll, but the error is worse, the program doesn't run at all. When I clicked on it, it immediately said error and the only option was to close it.
is there a null value in labview?
how can I pass a null into an array?
Time zones and time stamps
The "Get Date/Time in Seconds" function returns a time stamp control that appears to contain the local date and time. Is there a way to convert this to UTC without doing a bunch of crazy tail math / logic? I mean, to do it correctly required a lot of "thinking" to account for daylight savings, leap seconds, and so on... I hope I am overlooking something very trivial. I would prefer to avoid having to make OS calls to query the local time zone, etc if possible. Our system clock is steered by a GPS time server, so the system time is fairly accurate, but for convenience is also in local time. However, we would rather use UTC for creating file names and for timestamps in the files to avoid possible conflicts surrounding the crossover to standard time. (Some of our processes are now 24/7 so this is something we have to consider. George Gatling Applied Technology Division, SFA Inc. Space Physics Simulation Chamber US Naval Research Laboratory 202-404-5405 (phone) 202-767-3553 (fax) If trees could scream, would we be so cavalier about cutting them down? We might, if they screamed all the time, for no good reason. --Jack Handy
Re: How to convert an array of bits into an array of bytes?
Thanks very much Altenbach. Van
Re: how do i prevent the default 0(if for example) from passing forward?
cn_tower; You need to provide more information. Better if you can provide the code for review. You can always delete a case from the case structure. Right-click on the case and select "Delete case". Regards; Enrique
Internet toolkit problem - growing Active Connections list
When I built executables with G Web Server, sometimes, the list of active connections start to grow and whole system seems to stop responding for CGI calls. Does anybody know what could be the reason. Thanks in advance Pawel
RE: import entire cluster at run-time
That was a perfect solution! Thanks! Today is my last day as an intern with this company, and I wanted to thank everyone who has made suggestions and helped me with LabVIEW. Hopefully, you won’t see me again as I’m not really interested in continuing down this more software oriented EE path. Anyway, thanks again. allen -Original Message- From: PJ M [mailto:[EMAIL PROTECTED] Sent: Monday, May 17, 2004 16:14 To: Himes, Allen Cc: LABVIEW INFO Subject: Re: import entire cluster at run-time Hi, If you strictly type def your cluster (customize control>Strictly type def>save), the user interface will reflect any changes you make to the cluster. Actually, any places in your code where you use that cluster will reflect the changes (as long as you are using the strictly type def cluster). PJM "Himes, Allen" <[EMAIL PROTECTED]> wrote: Hey all, We're trying to create a user interface that runs another stand-alone sub-vi. My vision is to grab some sort of input cluster from the sub-vi, display it in the user interface VI, and choose options from it. Right now, we're able to grab the data from that sub-vi's input cluster via a Reference, but the input data is not important. We just want the form of the input cluster to appear in the user interface VI. By just copying the input cluster directly to the user interface VI, this process is pretty easy. The catch is when the sub-VI changes, the user interface VI must be changed manually. Any suggestions? Thnx, allen Do you Yahoo!? SBC Yahoo! - Internet access at a great low price.
Re: Embedded LabView on an independent chip?
I only know of being able to program the NI FPGA PXI card with LabVIEW. I haven't heard anything about DSP's. Here's the link to the FPGA card: http://sine.ni.com/apps/we/nioc.vp?cid=13713&lang=US and one on LabVIEW real-time development and deployment: http://www.ni.com/realtime/ "Matt Moose" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > I've read that it's possible to develop LabView code for a standalone > chip, such as an FPGA or a DSP; I'm not too sure of the details. > > Please can someone who knows this field well point me in the right > direction? I wish to look into running LabView on an independent > embedded system of some sort. > > Best wishes, > > Matt
Re: What is anti-aliasing?
If your signal has frequency components that are higher than the Nyquest frequency (half your sampling rate), they will show up as alias frequencies that are lower. This can cause false results. Your analog signal must be filtered such that only frequencyies suitable for your sampling rate are digitized. Look at some of the information here at the NI site, e.g.: http://zone.ni.com/devzone/conceptd.nsf/webmain/2EAC3B85027D8EE5862568C0005554AE?opendocument or http://sine.ni.com/apps/we/niepd_web_display.DISPLAY_EPD4?p_guid=B45EACE3DBE356A4E034080020E74861&p_node=DZ52008&p_submitted=N&p_rank=&p_answer=&p_source=External
Re: How to convert an array of bits into an array of bytes?
--6371056.1085161087048.JavaMail.quiq.tekken Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit For your reference, here's an image of the code (since you don't have LabVIEW 7.0). --6371056.1085161087048.JavaMail.quiq.tekken Content-Type: image/gif; name=pack10.gif Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename=pack10.gif Content-Description: Code Image (same front panel as better example below) R0lGODlhUQGRALMAAAB9AP8A/0pN/5yanJya/7Wyzv///wAA ACwAUQGRAAAI/gATCBxIsKDBgwgTKlzIsKHDhxAjSpxIsaLFixgzatzIsaPHjyBDihxJ sqTJkyhTqlzJsqXLlzBjypxJs6bNmzhz6tzJs6fPn0CDCh1KtKjRo0iTKl3KtKnTp1CjSp1KtarV q1izat3KtavXr2DDihUJgGDZBADSHlQ7tq1biGcFlo0bdyDbt3jzGqw7127Bs4DRCgbMlq7ew1T5 yr3rVzBawnsdS0ZMualiw2blat68uPDkyqCTXm7cOW1fzphPh159dDTnyaoxS67LuvZQ03QZw55t 1jRp28Dd0g5OHOzw4siTK18ucYDz59CjS59Ovbp05thLDvDoPOL27OBB/m63Tn56gu7ln58Pz77j eIHfuzc/P96A/fv4779vr1J3yuM5vaeefN7Rd15+CNq3H39/AYiRgydBaJOA6H1XIHr2JaTgegw2 CJKEJYFI03jmPSbiehgaoKEBC3boWGB9ERbYayZ21qCMueV4Y2l2+dZjYZ7J+OOQHLVooGwKkXig ightaKGLMwIZGZKGDVelX1cqFBtvU2I542BYikffdUgmpOQAGSZQwJoEOeliY1/y5aNqqH3GW5W4 PbaWb1naieOWmuE214kXmlcmQmdmWMBAiwrk5puCAsolnXdGFmiYeyl26aaflSkbpYu5x+FA3R16 UKIqNqrmQI9Cmdmn/6RZiWlmnEq6W61cvtbnrrRuRCKZv5lpIJqpMsoqi6N26BpsPtpZo7Nzwgmk lXxKy1iez8qp47NFolhhrkkOq6ixjiL75JsTEboahUpyuxCqqwqkaqvopgvefvGd6xC8qs5rbr0A v5usgfOlKC+bxxrZXnoMR1fcrw1bJy6TB9HLX8QRP4xxw0uuqDB7BEZ0wMgkj0wAAQEzVF+C+X0c HoHqNWTyySSfnLLAxLKs38ALW6ivQiUTUDPKNwvL8c8v+1zQt2MmEDQAMxctLERI36s0Qd9W+DTU Nkt96sZvwrx0u+ptDUDXXr9bdb1iY30miWajnbaZa6PbNqlv07f1Af5yz/313Hfj7XN3T0ftN92A X+1Q0EMfjnjaMIcMNN80G+64QZLfnPniJTd+OeZ1h71xep+Dnvjo5JU+tuqIhs666a+vHvtDm7Ne ++x/4w6f67rf3pK6NErlu+54xxTtq1re2ixSwxNPsEt99rrWbqYO1Tzx14+EZ5DTbrYs8AHyjrt8 4HN0PJie6mqjUtmPv51/Ec4aY4+0fs+++LM7BwAC5WvEK6WeoV6witK+/O2Pf7+TH5j+4j3kBY8o BYzdARH4u2lFaVBfMtG2khJB1k2QgkLpHwHx1xP4JQYBKEShCF+yQuuRkCf7MyFUPqhC91kmhTK8 YQpruBLUlUd4L/7cCQ1zqBQagjAlQRRYVDooxB3isIUzwZZcnHhElAitcySrSBJ9wkSdGPGJrQGA AAQQKSpCkSJXnNkV9xWyLfakizmZYFrMeMaVxHCMacHjByPFR5GkkW8loxrWgKhD/slxjoYMygHF SEZGIpJ/VHRiDEOSxrMFkmkxI9Ugl+jGm8QQN4YMpQrrSBJB6VGPMRwlIkHJQ49UEmpZzFq74LNJ qPjwlrhMzydNE8pHjjIACQCmMINJzGEas5jIPKYyk8nMYcpxjNCEZipVeMpG4jCX1HklLA8wrHyd 60md3Ak2x0nOASzykKKU5DLX2cx2svOdxXxmNKUJSRxGc5r8K/8ndLQZy7y1sZa42+UcBzpEUobk kKZBZT3tSUYV4hAkr7ykP8EJ0NkJ9JPpJGIUI+nIc+7QkTisIkcq+cfdDe6bFZXgKD+6SoOWkqN6 5B8qGTlTlxbkjyWlXUpf51E6hpCPHZVpQzuKx5LgtHJspCjxvjhKpghqpdiSIiWxmEWKhLNeX9So UYxo031xx3kFPaEkWaLPTAYUjFXhqvOcmsirDHGtTu1qEx8K17raha52tesi88rXSfI1r1r9qwcF S9jCGvawiE2sYhfL2MY69rGQjaxkJ0vZylr2spjNrGY3y9nOevazoA2taEdL2tKa9rSoTa1qV8va 1rr2cnKN7PLHKkIoWZHloAiJLWLrWFtLfSi2ANLtYYVkQSLFqHsaXN/6Zpsa5DqwV9rSk3Kjehfh GjZKuMLTA7dkW3BFj0rb7VQD/wen1GJ3gei1VZ6iVyf1BSpH15LqALH7v6iat4HprVR789td8KIG VAycXoBhpMDumva83FVgndibK00JMLwLHnB2FWxetdC3WeeT7nql5SF38QjDJkzNbxBc3TlV97UB RjFyrKviFrv4xTCOsYxnTOMa2/jGOM6xjnfM4x77+MdAFkt7 --6371056.1085161087048.JavaMail.quiq.tekken--
Re: How to convert an array of bits into an array of bytes?
Thank you Altenbach. You're a life saver. Van
Re: What is anti-aliasing?
This article might help: http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/68f14e8e26 b3d101862569350069e0b9?OpenDocument "uscmagz" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > I set up an FFT Power Spectrum and someone told me I may need to do > anti-aliasing for some data I'm reading. I understand it has something > to do with harmonics. Is this something that can be done in LabVIEW or > is this a hardware issue? > > Thanks =0) > > Lauren
how do i prevent the default 0(if for example) from passing forward?
how do i prevent the default 0(in the case structure for example) from passing forward? (i.e. don't wanna see 0s in my output files)
Re: How to convert an array of bits into an array of bytes?
Thank you Altenbach. Can I ask you to save this in a 6.1 version? I don't have version 7.0. Thank you, Van
Using LabView server , is it possible to use the multicast...
Using LabView server , is it possible to use the multicast protocol to send VIs to clients using Run Time Engine? I need to know if it is possible to configure Labview web server to send remote control information with multicast protocol
Re: driver problem
Hello! Take a look at the following document: http://digital.ni.com/public.nsf/websearch/78171449AECA0EB286256CE5005205A0?OpenDocument";>Receiving Exception Error in Call Library Node This should fix the problem. Sylvia Vences Applications Engineer National Instruments
Re: What is anti-aliasing?
Hi, anti-aliasing is smoothing. This term is usually used in computer graphics. In graphics anti-aliasing is used to smooth some distortions on the pictures (for example big squares in zooming). As every smoothing anti-aliasing is some kind of lowpass filter. So I think that advise was to perform some filtering to remove highfrequensy components from your signal. Good luck. Oleg Chutko.
Re: collating sequence error???
Hi Scotty, We need some more information from you: 1) What SQL query are you trying to execute? 2) What operating system are you using? 3) What version of Access do you have? The database connectivity toolkit is ADO Based. Try creating a UDL for the database and feed the path to the UDL to the Database Open Connection.vi. To create a UDL, go to Tools >> Create Data link. Under Provider tab, select Microsoft Jet 4.0 OLE DB Provider. Under Connection tab, select the database you are trying to communicate to. Test the connection to make sure it is connecting ok. Start with a simple SQL query and see if that works. I hope this helps. Sincerely, Feroz National Instruments
Re: collating sequence error???
Hi Scotty, Please take a look at the responses posted to your question at the location below: http://exchange.ni.com/servlet/Redirect?id=11097202";>collating sequence error??? Sincerely, Feroz
Re: collating sequence error???
Hi Scotty, Please take a look at the responses posted to your question at the location below: http://exchange.ni.com/servlet/Redirect?id=11097202";>collating sequence error??? Sincerely, Feroz
Re: Trying to synchronize switching times VERY precisely
Hello Kelly! Essentially, it sounds like you are wondering how accurate the wait functions in LabVIEW are. The timing accuracy of a Windows-based computer is typically 1ms, so at first glance the answer to your question is approximately +/- 1ms. There are several things that can affect the timing of a VI, however, such as other applications taking processor priority and other functions inside your VI taking longer than the wait time specified. In general, if you are needing accurate timing, take all of your other operations 'out of the equation' (i.e. remove them from the loop if possible). A lot of the time, very accurate timing can be done at the hardware level. Depending on which hardware you are using, you may have the ability to use an onboard clock to control your analog output. This is known as 'Waveform Generation.' See the NI Developer Zone tutorial on http://zone.ni.com/devzone/conceptd.nsf/webmain/3B13FEA05458E2E286256802007B91DE?opendocument";> Waveform Generation for more information about hardware timing.
Re: record ECG during MRI scan
Unfortunately, I do not know enough about how to filter this noise out in software. Using shielding may be the best way to go. However, one last suggestion is using a reference signal, however, this will require knowing the frequency of what we are trying to measure. Check out the http://zone.ni.com/devzone/conceptd.nsf/webmain/20B6BDBE462C6E5286256CDF00752680?opendocument>LabVIEW Lock-In Amplifier. -Justin T.
I have an interface (main vi) wich call another interface...
I have an interface (main vi) wich call another interface (pop up).this interface call another interface. How can I do in order to close the interface which is calling without stopping my application I have an interface (main vi) wich call another interface (pop up).this interface call another interface. How can I do in order to close the interface which is calling without stopping my application.
execution/exit of DIO single read/write.vi
Hi all, System - Windows NT4.0, LabView 7.0, PCI-DIO-96 card. Info - I am using the "DIO single read/write.vi" to update ports on a custom board. The Labview code has an outer For Loop that executes 64 times (to update the ports 64 times). Inside the loop is a sequence structure. The first sequence frame uses PPI B Port A of the DIO-96 in output Mode 0 (no handshake) to update one target port. The next frame uses PPI A Port A in output Mode 1 (handshake) to update a different target port. The DIO PPIs are always used in the same Mode and the same data direction. Question 1 - When the vi executes, does it look at the iteration input and leave the PPI config register alone if the iteration input is nonzero? Specifically, during my system init routine, the input is wired to the iteration terminal of the For Loop. Later in the code (after exiting init) the vi is used to do updates in other structures. I want all subsequent executions of the vi to be the same configuration as initialized. If I tie a nonzero numeric constant to the iteration input of the vi during subsequent executions, will the vi leave the 8255 in the same configuration as when the init routine was exited? Question 2 - I need to wait for the handshake in the second sequence frame to complete before the sequence is exited. I assume that when the vi is used inside of a sequence, it is analagous to a subroutine call. Does the vi wait for the handshake to complete before returning? In other words, will the vi complete the handshake with my target port before the sequence frame is exited? If not, any suggestions on how to wait for the completion? TIA - Charlie
What is anti-aliasing?
I set up an FFT Power Spectrum and someone told me I may need to do anti-aliasing for some data I'm reading. I understand it has something to do with harmonics. Is this something that can be done in LabVIEW or is this a hardware issue? Thanks =0) Lauren
Expression node and numeric units
Title: Expression node and numeric units Yesterday I went to a talk regarding software development with quality assurance for dimensional consistency. The talk was aimed at developers using Fortran to create predictive model of physical processes. This prompted me to review how LabVIEW treated units and conversions. To my pleasant surprise it handles units and conversions very well. It even handled mixed system (adding or multiplying inches with metres). The problem that I did find was using a unit value with "_expression_ node" primitive. That is, when I wired a numeric control with a defined unit (in this case "m") to an _expression_ node, I get a bad wire connection with the associated error "You have connected numeric data types that have incompatible units". Same problem when I tried with and "formula node". I checked the Labview help file but the issue is not addressed. Is this a fundamental limitation of the _expression_ and formula node or is there a way to use these primitive with variable with units. Paul A. Rochefort IMD branch AECL Chalk River Laboratories
Re: need to know the highest version of labview that was released for HPUX
Hello! The latest version of LabVIEW for HP-UX is LabVIEW version 6.0.2. Thanks for contacting us! Regards, Colin C. Applications Engineering
Re: Est-il possible de changer le curseur de la souris sous labview?
Monsieur, Aussi, vous avez la possibilite de modifier le curseur de souris en LV en appelant directement les fonctions du SDK (Microsoft) dans LabVIEW. Veuillez trouver un lien ci-dessous vous expliquant la demarche =E0 suivre: http://zone.ni.com/devzone/conceptd.nsf/webmain/6ED4643F866A68F4862567CA007= 886D1?opendocument Cordialement, France.support
Re: How to control a solenoid using LabView w/ a NI PCI-MIO-16XE-10 DAQ?
Yes this will work fine. Please add a flyback diode to your solenoid current. That is a diode to flow current from the negative terminal to the positive when you cut current to the solenoid. The back EMF spike can be quite high when the coil field collapses.
Re: HardCopy of Waveform Chart in LV in JPEG format or bitmap format?
thank u very much. Unfortunately, the VI can't run because an error occurs. "Joes Append Control Images to Report vi" is missing. I shall try to understand your example from the block diagram, even if it doesn't work
Re: CONFUSED WITH HEXADECIMAL FORMAT
1) If I send the command including curly braces I get response invalid command so that is not the right way 2) I tried sending just string and that did not work 3) 4) and 5) I am not exactly clear how would I send the command in this form. Can you use {02H} example and explain what you mean. The manual I have does not say anything more than what I told you and unfortunatelly there is no C or Basic example in it either. That would definitelly help. I contacted the tech support for this device and this is reply: "Using 02H in your program will probably work because it should know that it is hex". All I know is that whatever I tried so far my response is "FF" which means invalid command. I appreciate for help, Pedja
RE: Slow Printing
I didn't think the absolute path was necessary either. However, I kept getting a "VI not in memory" error. Most likely, I wasn't waiting long enough for the application to fully launch. I was hoping that as soon as the Open Application reference function was successful, the Open VI reference function should work. I'm not entirely sure why, but when I use the full path, it works much better. In my testing, I was using the System Exec to launch the application followed immediately by a looping attempt to Open Application reference. I could have used the Wait (ms) function, but I do not like depending on a fixed time for an application launch. We know that apps launch in varying amounts of time depending on the platform and specific hardware. Oh, and Scott, I agree! I would love to run with OS X. My first several computers were Apple IIs and Macs. I was forced (kicking and screaming) to the PC platform. I'm in an Alliance Member company and our customers nearly universally use Windows. So, I'm stuck until some Mac-friendly research lab grants us a large enough contract for me to "make the switch". By the way, the approach I described for printing can apply to a whole host of things. Basically, it is a way to give yourself more than one UI thread. Anything that insists on running in the UI thread (e.g. non-thread-safe DLL) is a potential candidate to be "outsourced" to a Service app. Daniel L. Press PrimeTest Corp. www.primetest.com
Re: How to do timestamp conversion
> I want to convert this timestamp to string. Use Format Date/Time String. > Also how to compare timestamp data type with string > timestamp. Because i want to read the time stamp > from file and compare with current timestamp. Why can't you save the time stamp value instead of the text? That would be much easier.
Re: I wish to program my mass flow controller through labview
You should be able to meet this objective -- however, your going to need to be a little more specific with what you have (hardware) and what the issue is.
Re: Is there something to reset all indicators when the VI is open?
This doesn't work. The option you mentioned was not selected, but now it is. Indicators are not cleared when I open the VI. Maybe because I don't know what is when you say: If your subVI is set to open FP when called My main VI is set to open Front Panel when called. I don't know what about the subVI. But, the most of the indicators are in the main VI. More over, I don't know what you mean with: If you open the panel using VI Server
Re: collating sequence error???
I've not had that specific error. Can you execute the SQL command in the DBMS on which the DB was developed? Can you execute the SQL query in an interactive SQL editor on the Labview system? One thing you may find is the ODBC driver, which in this case appears to be for an MS Access DB, may not support all of the SQL commands that you may have used with other systems.
Re: Is there something to reset all indicators when the VI is open?
Thank u for your attention. I am sorry, but I have not been able to do what you suggested. Your picture is nice, but it is impossible for me to reproduce it because it uses Functions I have never seen (I don't even know their names...). Could you please be more precise? I am a new user.
Re: Is there something to reset all indicators when the VI is open?
Do u mean to look at NI Example Finder? I have got LabVIEW 7.0, I have tried the Search option, but I have not been able to find what you suggested. It says: "no examples match your searcg criteria"
how to draw multiple charts from multiple data acq. loops
I am gathering data in 3 embedded loops, call the innermost "frequency," middle loop "sample #," outermost "temperature," typically 1-10 frequencies, 1-10 samples, and 50-100 temperatures. For each measurement I get 2 numbers, called C and D. I want to create a stripchart for each sample running with "temperature" across the X-axis (temper. is equivalent to the acquisition count), and 2 plots for each frequency-- C and D. I guess I'd like to use different colors for each frequency and solid vs. dashed lines to differentiate C&D. I haven't been able to gain control of the stripchart VI to separate the various data streams.
How to do timestamp conversion
The timestamp value from Get Date/Time in seconds gives the current time. I want to convert this timestamp to string. But there is no ready made function to convert timestamp data type to string. Also how to compare timestamp data type with string timestamp. Because i want to read the time stamp from file and compare with current timestamp. Please help, Thanks
Re: Best way to learning labview for begniners
sattu; LabVIEW includes tutorial you can follow. At the splash screen, click on LabVIEW Tutorial. You can also access the tutorial from the Help. Make sure you also look at the different examples included in LabVIEW. Check out the http://zone.ni.com/devzone/labviewzone.nsf/OpenPage?openagent&lvsection=labviewzone";>LabVIEW Zone. Also, look at the LabVIEW http://forums.lavausergroup.org/";>Frequently Asked Questions (now at the LAVA forums). If you are very interested in getting deep into LabVIEW, make sure you subscribe to http://www.info-labview.org/";>Info-LabVIEW Mailing List. If you become very enthusiastic and want to contribute to the knowledge base, you may want to join http://www.openg.org/";>OpenG.org. There are lots of information and references in the web, but your starting point for looking is at http://www.searchview.net/";>SearchVIEW.net. But nothing beats the best way: roll your sleeves and get you hands into LabVIEW. Don't be afraid of even crashing your computer. And above all this, don't be afraid of posting your questions here. You will be amaze of the amount of knowledge you will gain by asking and "listening" to what others say about LabVIEW. Regards; Enrique
Re: Best way to learning labview for begniners
Hi Sattu, NI run some excellent training courses for LabVIEW, contact your local office for details on their basics 1 and 2 courses. Hope this helps, Nick
Best way to learning labview for begniners
I am new to labview could any one please tell me the best way by which I can learn labview?
RE: Slow Printing
"Dan Press" <[EMAIL PROTECTED]> wrote: >I create a separate application; let's call it the "YYY_Project Print >Service.exe". The application's job is just to sit there, but its INI >file configured the VI Server to listen on a port other then the default >3363. See the app note -> Overall a very interesting and good idea to do!! >Remember that built apps act like folders when you want to open a >reference to a specific VI. Just wire the path to your printing VI such >as "C:\My App\YYY_Project Print Service.exe\Print Me.VI" This is not necessary. In built applications LabVIEW (since at least ~ 6.0) always searches the internal "LLB" for a VI with the last part of the path first before even attempting to locate the VI at the absolute path if any given. So for this one you can actually use a string with the VI name only instead! Rolf Kalbermatter CIT Engineering Nederland BVtel: +31 (070) 415 9190 Treubstraat 7H fax: +31 (070) 415 9191 2288 EG Rijswijkhttp://www.citengineering.com Netherlands mailto:[EMAIL PROTECTED]
Embedded LabView on an independent chip?
I've read that it's possible to develop LabView code for a standalone chip, such as an FPGA or a DSP; I'm not too sure of the details. Please can someone who knows this field well point me in the right direction? I wish to look into running LabView on an independent embedded system of some sort. Best wishes, Matt