Re: I have a for loop with 15000 iterations, and i'd like to...
Greetings, Naddad: What's wrong with using one of the several available Labview progress bars? That way you won't have to keep dipping into the windows application, which should speed things up considerably. (Besides, the Labview bars are a lot better looking than Windows bars, IMHO. :) Eric
Re: Analog trigger with raster scan
Dear Slimbim: At what point on the flyback are you triggering your acqusition? Depending on how steep the slope is on your sawtooth, you may need to build some kind of comparator, such as one that triggers when it drops to 50% of its amplitude, or some such. I imagine your electron microscope akready has a real trigger output available. I'd check the documentation on that first. Also, take a good look at your sawtooth with a wide-bandwidth scopeyou might find the rise (or rather fall) time of your flyback isn't all that great!You might need to build a schmitt trigger to speed things up a bit, if you're undaunted by external hardware! Just a few suggestions.. Eric
Re: How to control an Electronic Load to give me a constant power output.
Dear Wrath: Do you know if your load is a constant impedance (or resistance)? If so, all you need to do is assure a constant voltage across the load. If the resistance is variable, you must know the current AND the voltage. In either case, a simple feedback loop or loops in Labview should do the job. For a variable impedance load, you will need to multiply the current and resistance to obtain a power reading, which, in turn will be used to adjust your output voltage. ( An iterative shift register, where you compare a current value to a previous value is a simple, stable way of achieving a feedback loop). I will be glad to work on this code with you. Eric
Re: function max value
Northwind: Why certainly! Just look in the Math subpallete, and you will find zeros and extrema vi. Alternatively, you could save the function as a waveform and use the wave max/min vi. Eric
Re: Congratulations, Dennis Knutson!
Congratulations, Dennis! Your productivity is astonishing. Having just achieved 10% of your output myself, I can appreciate your dedication :) Most of what I know about Labview I learned on this forum, and you seem to have been there since the very beginning. Keep up the great work! Eric
Re: code wizard
Marko: If there was, we'd all be out of business! All kidding aside, Labview is written in a language called G, which can be manipulated within a C type structure. You might do a web search on G language and see what has been done. You might get some hints there. Also, look up GOOP. Eric
Re: SCR Phase Angle control
Greetings Nick: You should be able to get good results with your technique. (You're essentially doing a poor-man's Direct Digital Sythesis, when reading a pre-constructed table like you are doing) Another way to do this is generate a sine wave, using one of the sine generator vi's and then run it through a series of comparators (use comparison primitive) each with a different threshold. Add the values of each comparator output, and voila, this is your stepped wave. In this manner, you are simulating a flash A/D convertor. Another way to do this, is to run a square wave generator (say at 400Hz) and MULTIPLY this by a sine wave at 50 Hz. This will give you a Sine wave modulated square wave, (or vice versa, since mathematically, they are identical!) Eric
Re: Looking for ready-to-use indicator that looks like a horizontal-platform panel in an airplane
This can be done, but it will take some work. There are two approaches. You can use the PICTURE functions, and build the diagrams up a layer at a time. (Your PICTURE vi's are loop through, meaning you can take the output of one, say a grid, and input it to another, to overlay a pointer, for example) Another way, probably more labor intensive, is to use the property node to modify a button of some kind ( color, shape, etc) to make it appear like the indicatory you want. You might want to look through the NI database to see if there is anything similar that someone has written that you can embrace and extend to fit your application. In the meantime, you have given me a personal challenge! I think this would be a good extra-curricular project for me :) Eric
Re: Why is Time treated as an ugly child in labview
Greetings: You will find that in Labview, the squeaky wheel gets the grease! Until recently, EVENTS in Labview were treated as ugly children, now, the entire architecture of Labview is event driven. This change was brought about only because of vocal popular demand. I believe more input from users like you (and ME!) will eventually do for TIME what we've done for EVENTS. Eric
Re: Limit in waveform data size?
Dear Carnivorus: I would venture to say that perhaps there is not enough memory to complete the operation! :) All snide aside, working with large arrays takes some serious number crunching. You might try twiddling your swap file size (on the Advanced properties tab of My Computer in win2K and later). However, you're probably bumping up against the absolute limit of the OS. If there is ANY way of dividing and conquering your data so as to not have to deal with such a large array, I think you should invistigate it. YOu may find you don't need anywhere near the samples you think you do. (voice of experience,here!) Or perhaps you don't need the dynamic range. (On most DAQ cards, you can't change the number of bits, but you might be able to use a card with fewer than you're currently using) Eric
Re: Data Acquisition Question?
Greetings! Your application doesn't seem to be too demanding. Just about any Labview DAQ card will do the trick at such a low sample rate, and you might look at the DATALOGGING vi examples to get started. Good Luck! Eric
Re: I am trying to make a Phase Locked Loop and I have to...
Greetings: It looks like you need to increase your number of samples by quite a bit. Can you supply any more information, such as your sample rate, which DAQ vi you're using, etc? Eric
Re: how to send data as a stream to web site
Greetings! Are you familiar with PHP/Mysql? It will update a webpage based on data in a Mysql database. You can stream the fifo data into a formatted database, which will then be read and updated as fast (nearly) as you like. Poke around the web for PHP references; I think you'll find just the script to do the job for you. Also, don't overlook the Labview webserver tools. Eric
Re: Modify and control Power Point Presentations
If you use the Activex container, you should be able to pull down a menu with all the available controls (from the empty container control itself). Be sure you have installed all your activex libraries. Eric
Re: How to save data in a 4D array and make partial plots in real time?
Greetings! You can use any of the 3D display vi's to show your main 3d data, and then use color to represent your fourth dimension. This can be accessed via the property node. You will have to set thresholds for each color you use, which is quite simple using the comparison functions. As far as the data is concerned, the fourth dimension will be just another vector (column) in your data file. Also, check out the BUFFER examples for how to separate out running data in real time. As far as autoscaling is concerned, you might have to disable it, or alternatively, you could force a couple of dummy points into your data which represent the absolute min/max you should encounter. Autoscaling should generally be regarded as a default mode, just to get things rolling, it should not be relied on too heavily for serious data acquisition. It's better to use well-conditioned data, or some other means, such as a logarithmic scale, to allow access to all your possible data points. Good Luck! Eric
Re: how to test for cold soldering?
The DMM test is good, if you can wiggle or stress the connection while measuring the resistance. It's always best to avoid cold solder connections in the first place. Never never EVER blow on a solder connection to cool it off faster. This is a surefire guarantee of a cold connection. Also, avoid moving the connection until the joint is cool. Patience is always the key to good soldering. Eric
Re: Clusters: How to remove the 3D shaded background?
Don't you just hate it when that happens? :) Eric
Re: Clusters: How to remove the 3D shaded background?
Most things in Labview ARE, if you know where to look :) By the way, in case your input clusters STILL seem too crowded, you can change the size of the windows with custom tools...also, changing the fonts in the boxes can do wonders for visibility on a crowded monitor. Grouping by color background is a big help too. Also, be sure you have your display set for the maximum resolution and color depth possible. If you end up staring at your VI for a long time, it really can make a difference. Just a few hints from the peanut gallery! Eric
