Warren

Ya, I have two linear stages (the motors) that I control using the arrow keys from the keyboard. I had the loop set up for a fast and slow stepping mode and I used a timer (with different constants for fast/slow) that got the stages to step nicely so that if you held the keys downs, they would move continuously without any noticeable lagging. The resolution is 0.25 mm which is more than I need. I also have the code for the camera working well, but I'm having problem when I combine them. But to answer your question, I haven't had any problems with the GPIB communication. - Warren.

Hello, I was hoping to get some clarification on if/how this is possible: I want to have labview run two processes "simultaneously." I have been working on a program that will control a motor via GPIB and also display movements of the motor using a USB webcam. Origionally, I had both happening in a single loop (bad idea) and I found that with all this happening, the loop iterated too slowly and the motor controls became "choppy" and inconsistant. I want the camera to be streaming video constantly, but the motor only move if directed via a controller. I have the code to do this, but I can't get them to happen at the same time without the program lagging. Through reading other threads, I understand that it may be possible to do this using Event structures?, but I was under the inpression events could only be executed one at a time, and I fail to see how this would solve the problem?? If anyone could explain how this problem could be solved, it would be greatly appreciated. Regards, - Warren.

Thanks for the help! I have been looking into the interfaces. I think they may be what I had in mind, but I'm also curious about the container objects. I'm definately going to do a little research on them too. I also came across another possible option that may accomplish what I have in mind. Visual Studio and NI teamed up to create Measurement Studio. I know that VIs can be incorporated into that, but I have to see how easy it would be to access an external program using Visual Studio. Any comments or help links regarding this possibility? - Warren.

Hello all, I have a general question about the application of sub panels. I don't know enough about them, so my idea/suggestion may not even be possible. Through some experimentation, I have been able to open a "stand alone" VI within another VI that I made in its sub panel. As I understand, this is a fairly common place thing to do. However, my question is - is it possible to do this same type of procedure with a simple program that is not a VI, or even associated with NI software. I'm not necessarily looking for something that can send data back and forth with Labview, but just be opened and accessible within a sub window on my VI. For example, opening paint or something similar in a sub panel. - I realize it is much easier just to have the program running in another window separate from labview, but now that the idea came to mind, I'm curious to know if it can be done. Anyways, if anyone has any ideas, it would be great to hear them. Thanks, - Warren.

Thank you so much!

Hello, I have been using Labview to run a small executable, however I am having some difficulty. The program.exe will run when I execute my code in Labview, but I can't get my Labview program to continue its operation until the executable has finished, or has been closed. I have attached a small example to illustrate my problem. The executable I use is wordpad.exe (bc I think many people will have it) and it must be closed inorder for the labview code to run to completion. I was hoping to have labview and the executable run simultaneously - Any Ideas? Thanks in advance. - Warren. Example_exec.vi

Thanks, That works great! - I didn't think that was what Index was for. - Warren.

Hello all, I've been fiddling with some of the array controls and I can't seem to get this working properly. I think I'm doing it right, but I seem to be having issues with type mismatch. I've attached a simple example VI that illustrates basically what I want to do - I want to take a section of a 2D array and output it as a 1D array. [ A B C D ] _____________________[ B ] (I want the entire B column in case theres any confusion) [ A B C D ] -----> Grab sub array ----->[ B ] [ A B C D ] _____________________[ B ] * Labview tells me that this is a 2D array? Heres the Background if you're wondering: - I have a case where both the true condition and false condition output to the same place (register? - blueish block on the wired to the side of the structure?) Anyways if the case is true the output is a (should be) 1D array that is a subset of another larger 2D array, and if the case is false, the output is a constant 1D array. - Im having issues because the subset is not a 1D array and thus the outputs of the true and false conditions arn't the same type! Thanks in advance, - Waren.

Thanks for the suggestions everyone. That example "C:\Program Files\National Instruments\LabVIEW 8.6\examples\portaccess\parallel port examples.llb\Parallel Port Read and Write Loop.vi" is in version 7, and I've actually had it open a few times, but I can't get anything to happen. The LEDs are lit up but thats how they are when the computer boots. I've been taking a look at "Labview for Everyone" and it says that if the Baud rate/ other settings arn't the same as the specs for the port then nothing will happen, but for that specific VI I dont see an option to change them. In the end I hope to use the serial port to communticate with a PIC (but I guess I need to overcome this obstacle first)... If anyone has any experiance with that and could shed some light on this problem that would be great. Also, I'm kind of limited to the older versions of Labview because in the lab where I hope to apply this, the equipment is kind of dated - and Im told a new version of labview is not an option. (but I agree that it would be nice)

Sorry I took so long to get back to everyone. To answer the first reply: I have been sending single ASCII characters out, but on other attempts I have tried some hex and just binary (four 1's 0's randomly...as a shot in the dark) Im choosing the VISA port corresponding to 0x278...for me that should be LPT1 (some times all i can input is 278). Also I have Posted the Visa vi that I built quickly myself, but mostly I have been trying to get the built in examples to work..."Parallel port read / write loop" and "basic serial read/write" To answer AnalogKid: I am pretty sure the hardware is not an issue. Sometimes when I just boot the computer, the output pins are already tied high (I think) because the lights are all lit up, or only a few are...but I just have no control over it. To answer ShaunR: I have gone into the bios and taken a look at the options for the ports and I did have it set for "Standard" so I dont think that is a problem. Also, I took a look for the PORT IO example you spoke of in the "find examples" search and I could not find it. Currently I am using 7.0 (so that may be an issue), but I will head over to my other computer and check out 8.0. Am I specifying the output port correctly? Is the output to the LED's in the right format? Any other Ideas would be really appreciated. Thanks Again. - Warren.

I had hoped to set up this little experiment to learn more about Serial I/O to use in a future project - However I have had no end of difficulty just starting with this. I have a small circuit with 4 LEDs connected in parallel to (2,3,4,5) pins on the port. (I have 470 Ohm resistors in series with each of these) I have tied (11, 12) to ground. I have attempted to use labview to send some form of signal to the LEDs without success. I used both the serial VISA and out port. I have also reviewed the examples (Basics serial read write) but I think I have forgotten somthing, or I am doing somthing fundamentally wrong. I have also read through many online sites about the fundamentals of the Serial Port - but I must be missing somthing. Any help would be greatly appreciated. - Let me know if there are any details i neglected to mention. - Warren.

Thanks for the help everyone! - I got it working and I think its going to make organizing everything really nice. - Warren.

This is kind of a minor detail, but I'm going to be distributing the results of my data (and there's alot) and I was wondering if there was a way to include descriptive titles for each column of data I'm importing to excel (for example). I've been "Writing to Spreadsheet" a 2D array with all my data and I want to title each column. I've been messing with combining separate arrays of type double and type string (titles) in a cluster, but the "write to Spreadsheet" doesn't like that. If anyone has any suggestions it would be greatly appreaciated. Regards, - Warren.

Thanks for the reply. I'm still a little unsure how I would go about doing that - I had a good long google search, but I couldn't really turn anything useful up yet. (I probably don't know enough to ask the right questions) but I think I might have figured out a way to circumvent the ugliness and still accomplish what I need to. Ill let you know if it works out. - Warren.

I have a question that is similar to what PSUstudent was asking - (Im not sure if I should have made a new topic for this.) Anyways, I am conducting an experiment that records/ displays an input signal from a lock-in amplifier. - this process is already done. However I want to be able to select the data that I am recording remotely - from the other side of the room. I was thinking that I could build a toggle switch near my experiment bench that when turned-on would activate the recording process. - Ironically, This has turned out to be more of a problem to understand/ build than the actual experiment set-up. My question is how can I take a constant voltage and trun it into somthing meaningful for labview? I have already taken a look at the "basic serial write and read" example, but still feel like thats not exactly what Im looking for. Any help would be appreactiated, or an alternative soultion. Thanks - Warren