Jump to content

mross

Members
  • Content Count

    532
  • Joined

  • Last visited

Everything posted by mross

  1. Can anyone tell me if there are some VIs for linear algebra and matrix math using extended precision? Thanks, Mike
  2. Shaun and JG, I have been doing this for long enough you would think this little tidbit would have been noticed by me, but I have a habit of not auto-indexing when there are complications. This time I did it and noticed. Thanks for the help, Mike
  3. Howdy all, I am learning to work with TDMS. Maybe that is the source of the problem... I have a for Loop that runs one pass and stops even though i have wire a 4 to the count terminal. I do TDMS open, run some arrays to the border for indexing. In the loop I want to TDMS Write some numbers, several times, then loop and pick up the next index, write, and so on. Outside the loop is TDMS Close and I call the File Viewer. I get no errors. I cannot get the loop to continue past the first iteration when it lets the output data go to the TDMS close and everything stops. I may be messing up
  4. I never see the printer ports (Have a USB one, not parallel). I have given up on the Prolific chips sets for serial com converters - maybe that is what you are using?. FTDI seems to be less troublesome. EasySync is their outlet
  5. Shaun, The fellow I work with is taking a controls class from the same prof I did 20 years ago (so I know he is worth listening to). He was reported to have made a provocative statement to the effect: People are always trying to come up with some special algorithm for control, but after screwing around, and around, and around, they always find out the PID would do it better. (my words again) He believe meant that to cover even the asymmetrical case (that should be defined in more detail probably). I suspect he is very good at ferreting out the P, the I , and the D. But that is a weigh
  6. Ned, That first sentence is interesting to me. "PID is designed to drive an analog signal, not a digital one." I will soon be wiring to control fluid temperature by varying two streams, one hot, the other cold. I definitely thought I would use PID, but you have me wondering - my control means is to send RPM commands via Modbus to VFDs in charge of pump motors. The plan is to use cRIO, FWIW. simplePID.vi was recommended to me as a starting point, I haven't gotten that far yet. This is digital output not analog. Do you have any advise? My goal is to be able to change from one steady sta
  7. This has become an exercise in social engineering and language, very interesting. Mark posted the questions below in the thread quoted above, have these been addressed? What is the final data going to be used for? No discussion of the purpose of the result What does the data represent? No discussion of the real implications of the input data. Why do you want to average / smooth the data? No discussion. What does the peak and valley data tell you about the waveform? No discussion. How do you know if the program is doing the right thing? No discussion. Those questions are r
  8. Hello Flower, I am also building a sun tracker so I am interested in your project and progress. Perhaps we can stay in touch about this going forward. Unfortunately, I did not find the attachment you mentioned. It has been a while since I used LAVA - in the past it was necessary to upload vi's to the LAVA storage area where interested people could have access to it. I originally planned to have my tracker stop at sunset (sunset can be in a lookup table or calculated) and cycle to a park position (collector in a horizontal plane to reduce wind loads overnight when it is not necessary to tr
  9. QUOTE (jackmax @ May 19 2009, 09:43 AM) Sorry, I can't use LV8.6.
  10. QUOTE (jackmax @ May 18 2009, 10:56 AM) You should show us the VI. There are too many reasons for the buttons to lock so that information is not useful.
  11. Yair, Thanks for that bright and concise philosophical discussion. Not being a student of computer science I couldn't have begun to describe the distinction. I know controls, wires and indicators are not variables in the C, Basic, Fortran sense, but I couldn't have begun to say how they differ. I was taking the similarity more from the English/mathematical word (as apposed to Computer Science) "variable" - a thing that is quantitatively changeable - magnitude, direction. A wire IS variable since it can represent alterable quantity, or in the case of wire representing a string, changeabl
  12. QUOTE (lovemachinez @ May 14 2009, 10:54 AM) Yes and No. A LabVIEW variable can do similar things compared to a C variable, but it is more interesting and useful becasue it has a visual aspect Tim S answer was just fine, but I will add a more. Nobody ever writes all this down because most people learn it quickly by being shown by an experienced user. When learned this way the simplest things seem obvious. But, if you have progammed a text based language and come to LabVIEW alone and with no guidance, then even these small things are difficult and NOT obvious. I hope the following
  13. QUOTE (Michael Malak @ May 13 2009, 07:29 PM) You should look at the capabilities of VI Server. You can start up many new VIs that way. However, you cannot cause new graphs on the front panel of a VI which is how I interpreted your query. You can only hide and show them by various means, or put them on Tabs and change the visible tab - programmatically. Here is a little demo of how to use the Open VI Reference you mentioned. This example was written for a someone else, but it is useful as an general example. It shows how to call and open a VI and its Front Panel independent of the c
  14. QUOTE (Michael Malak @ May 13 2009, 04:14 PM) You can't "dynamically instantiate" anything without scripting, and that is not where you want to go. We are trying to offer you solutions not pipe dreams. Did you try a tab control? You can put graphs on different tabs and programmatically cause different tab pages to be visible. Or with much more trouble you can move the locations of the various graphs so they are visible on screen, or they are off screen. If you try to manage that with 64 individual graphs you are in for a long, boring, job that will be of limited use to the user.
  15. QUOTE (Michael Malak @ May 11 2009, 07:21 PM) Michael, You didn't ask for this, but I will give it anyway. I think it contains the ingredients of a better solution than 64 little graphs. There are other ways to do this, but this one is basic and shows how arrays are manipulated. The attached VI shows a way for you to overlay any of the 64 channels in one large graph. I made fake data in 24 rows of 40 data each. The rows are like your channels. All you need to do is wire your data array into the same input tunnel as my fake data. The UI lets you enter the channels and turn them on
  16. QUOTE (Michael Malak @ May 11 2009, 05:08 PM) Michael, It sounds as if you want to display 64 graphs simultaneously. From a usability POV that is not a great idea. You could instead choose what you think is a reasonable number of graphs to show at one time, like four for instance. Then you can change which of the data channels you want to show in each one. It would also be possible to have multiple channels overlaying in the same graph, four graphs of eight channels (this is surpassing what I would call usable also). One graph with eight channels overlaid would be useful and very doa
  17. QUOTE (petersrule2003 @ May 4 2009, 08:52 AM) I am sorry, I overlooked the information about this being a serial comm setup. You should verify that the serial read operation is providing useful data by looking at that data directly. Wire an indicator or attach a probe to the output of the VISA Read. I can't see any data to review the conversion because I cannot run your application. The data is lost when you save the VI without making the data in the the various indicators default so it persists when you send the VI to us. All serial data is encoded in some manner and you have to de
  18. QUOTE (petersrule2003 @ May 3 2009, 01:57 PM) Looks like a much too low sampling rate (your rate should be 10 times faster than the frquency of the signal of interest). And a full wave would not go to zero, so there is something wrong with the way you are wiring it up. You can count on this: the graph is showing you the voltages you have applied to the terminals of the DAQ card. I bet it you put a real scope on the same points, using the same scale and sampling rate you will get the same sort of readings. Also, if you are putting -120 volts directly on the DAQ board (you did not menti
  19. QUOTE (iriszhaoyu @ Apr 28 2009, 07:31 AM) A simple way to do this: You can perform the basic math functions on arrays - add two arrays and they are added cellwise, New Array (0,0) = Array1 (0,0) times Array2 (0,0),...New Array (m,n) = Array1 (m,n) times Array2 (m,n). Also subtraction, multiplication and division. By creating a set of arrays like you have described in your image, you can then add them and divide the result by the scalar number of arrays added. You can create the new arrays by simply using delete array element to eliminate the first element of the original array, then t
  20. QUOTE (Pollux @ Apr 6 2009, 09:09 AM) The VI is doing only what you asked of it. Please investigate some example code on the use of the Event Structure. You will see that the event structure is always enclosed in a while loop structure. This is how it repeats more than one operation. When have an while loop structure you will need to create a means to stop the loop. I see also that you do not have the concept of wiring data. This is so very basic that is is hard to be of help to you. You need to start finding and using example code to learn how LabVIEW works. On the block diagr
  21. mross

    Moving hand

    QUOTE (raymyster @ Apr 6 2009, 08:07 AM) Yes, LabVIEW can do what you want. LabVIEW will do it much more easily than C++. But interfacing... I have not done that. I stick to LabVIEW. I do not see the point of lasers. You can use mechanical switches that cost a few pesos just as well. With a proper data acquisition and control system, you can sense and respond to continuously changing inputs which will be better for aircraft control. A binary system - hand blocking laser versus hand not blocking laser - is an ineffective way to control all but the simplest systems. How will you te
  22. mross

    Moving hand

    QUOTE (raymyster @ Apr 4 2009, 03:50 AM) So, what ideas do you have yourself on how you might accomplish this? Note on list etiquette: It is nice of you to be honest this is course work. But, even when it is not, it is still a good idea to have made your own contribution to the effort; the fact that it IS course work, and others may be working diligently without asking others to do it for them, makes it even more problematic to start throwing out solutions. It is even a fascinating topic. But, you really ought to lead with: "Here are my own ideas; 1, 2, 3, etc." "Here is how I am
  23. QUOTE (ssteven121 @ Apr 1 2009, 07:18 PM) I imagine that ni phone support will help you sort this out. If you have access to them a phone call will be the quickest way to resolve the issue.
  24. QUOTE (JustinReina @ Mar 30 2009, 12:31 PM) Justin, That is a very broad stroke. I know it was a throwaway comment, but I think it is unfair. I know too many working students and parent/students to feel this is a fair commentary. There are a lot of people who are slack, but it is not a fact of life for many. The un-slack are not obvious, you only see them in class, the lab, or the library; you don't see them when they are at work or at home caring for their family.
  25. QUOTE (Zest @ Mar 30 2009, 05:13 AM) I hate to say it, but if your mark in the course comes to this "poster" and you have not learned what is necessary to figure it out on your own, maybe you have not applied yourself to the course work with due diligence in the months leading up to this point. I suppose the class could also be poorly conceived and unfair, but that is generally not the case when a passing or failing comes to barely succeeding in one last bit of panicky work. I doubt if LAVA can help you become a success in this case (the 20 hours has elapsed as well I think). I am sorry
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.