Gabi1

QUOTE (Omar Mussa @ Aug 25 2008, 09:45 PM)

As long as it is your hobby/passion than it is worth it as you'll get the joy of a 'do it yourself' experience. If you are thinking it will cost less than going out and buying a 'universal remote' I think you are better off plunking the $ due to the time investment you'll inevitably make.

I meant in the sense of "how much buggy is LV PDA"? how different is it from LV "original"? is it going to be a frustration-does-work-at-the-end project, or a fun thing that will end up nice. i am looking for your experiences as a LV PDA developer.

i have never came across projects requiering PDA so...

Hallo Leute,

Challenge: my house is full of remotes. i dont stress it enough: FULL - DVD, HIFI, TV, projector, sat receiver, computer...

So I was toying with the idea of buying a universal. a worthy one (user friendly and actually doing what is needed, plus some programmed functionality) is just above my budget for the purpose (if i can manage ith LV...).

and then, i have my nice Windows mobile 5 PDA, with wireless and an infrared port (granted, on the wrong side of the PDA,but who said we cant turn around the LV buttons?).

So to make it run, all i need is LV PDA, (or some kind of server connection to my computer with the wireless), and the drivers for using the Infrared port as input-output device: the idea is to record the commands from the native remotes using a labview routine and DAQmx, and vice versa.

But: how do i get to use the IR interface? i have heard that one can instruct LV to use mouse for example as I/O device. is it the same here? how do i do that?

And also before getting into the hassle of installing LV to PDA: does it all worth it?

THanks for your inputs.

any chanceyou could save for LV8.2?

Thanks!

QUOTE (Norm Kirchner @ Jul 18 2008, 10:57 PM)

If you put Allowmultipleinstances=true in your built exe's ini file IT WILL WORK

if you look at the soft front panels that NI makes for things like their DMMs, they use that exact same ini so that we can have multiple dmm panels open at a time.

So since NI does it why shouldn't we.

It's much more elegant than making copies of EXEs

Thanks! had exactly this problem for some users who run identical instruments on same computer, just with different GPIB address.

Very cool! great creativity

Could be a great tric to confuse those who wants to look at the code, without knowing enough LV:

They would run it with open diagram to see... the actual horse(power) in the engine!

How many times did I forgot to set a boolean constant in a case to 'true', leading to an infinite loop condition??

in some project the run time is long, and therefore debug time is exponential: why not allow code change while program is in 'pause mode': i discover a bug - dont want to restart the whole process - pause, change the wire, structure or element - and then continue running.

It is possible in VB for example. works perfectly there.

Why not in Labview?

QUOTE (neB @ Jun 15 2008, 03:50 PM)

Is anyone clear on the language of the song?

The guteral sound is what made me first think Frnch but if its not french then maybe its hebrew. When I double clciked on Yair's link the YuoTube page had hebrew replies (since (I think) hebrew occationally imbeds words within words I don't know enough to be able to use my hebrew-english lexicon). I had once read that all hebrew music was written in a minor key (is that an over generalization?) so this music passes that test.

Hem Hem.... French being gutural? i dont want to get out of the subject here, but, again: French is gutural?? Spanish maybe, German definitely, but French?

nono, your other guess is better.

hello Yair

refreshing song. thanks for sharing it.

the graphics are well tought and worked. interresting while sad and in a sense horrifying.

the lyrics are not self explanatory, and i am not sure it is good. connection to the pitures is vague.

need to hear and watch another few times beofre i decide if i like or not. the whole thing is very artistic of a Bjork kind, yet surrounded by such sadness it is difficult to enjoy.

please do expand on its origin ( singer?)

QUOTE (Yen @ Jun 7 2008, 10:27 PM)

I'm still not clear on the details, but maybe this will help:

Instead of attempting to train the software, why not just write code for each case and then run each one until you don't get an error?

Alternatively, you can try writing identification VIs (which will only attempt to identify the format and then return the format type. You can have one VI for each format and build them using a standard connector) and then run those until you have an answer.

If you're asking about actully parsing the file, it seems to me that the Match Pattern primitive might help you, but it's hard to tell exactly.

Thanks yen.

i have 2 problems related: i do not know in advance how will the file look like. therefore, i would like a run-time solution, where the file to be read would pop up (or container), and allow me to click on the fields of interest. then if next file is identical, such identification vi would look versus its own built library of "clicked fields", and would not send the file to the container UI for definition of a new format type.

second problem, more basic: i dont see a solution to open the file in a container, and allow the mouse to click and get its response and field. i am sure this has been done before, so i am looking for some existing examples.

i am not yet programing this thing, as the file extraction is the critical element wich fails because of the tremendous amounts of different file formats. manual extraction on the other hand is a brain suicide...

QUOTE (Yen @ Jun 6 2008, 11:30 AM)

I still don't understand exactly what it is you want to do (and probably won't without some examples), but in any case, if you cross-post, you should include the link in both posts, so that people can see what replies were given in the other thread.

no response whatsoever on the other side, so...

let me depict to you:

i have 100 files, identical except the value:

"

NF=12

SXC 2 dB

PMD= 0.5

...

...

"

i want to extract the NF and PMD values. in this file format NF appear in the first line after the '=', PMD appear in the third line after the ' '. would be easy if i would be able to open the txt file, select with the mouse the string, and then the value, and store the field positions in LV.

Then i have another 100 files, but this time it look like this:

"

vendor...xxx

AP 0

NFa=12

SXC 2 dB

PMD= 0.5

...

...

"

this time the value of interest comes after the string NFa (rather than NF), and comes in the third line. no way to extract it without retelling the computer to refine his search. once i give it to the application, i would like him to keep this, so in the next file it opens it could try with the first criteria, and as the string comparison fails on the position, try with the second defined criteria.

some files come already in excel format, therefore it is easier to find fields. ultimately, after several such manual entries of string and corresponding field to extract the value, the application would be able to handle automatically any file format to extract.

i hope it is more clear, and thanks for your input.

QUOTE (tcplomp @ Jun 5 2008, 07:59 PM)

You could do this with Excel and the LabVIEW Report Generation Toolkit.

Open up the datasheet, prompt the user to select the data of interest, read (programmatically via .net) the current selection and you have your first match.

Ton

you mean create a macro in excel?

i have tried that, with minimum success. the problem stays the same: it will open a file, discover it doesnt go with its known format, and trow an error. make more elaborate VB to handle all that is out of my league and mainly of my available time.

i am not sure how the report generation toolkit would help me there. coul you expnad?

QUOTE (Yen @ Jun 5 2008, 07:25 PM)

If you want to search things by pattern, you might wish to hold the array as a delimited string, search the string itself and then find the number of delimiters before the match to know which cell you're in.

Hello Yen!

thats what i want. the problem is, i do not know in advance what is going to be the string before the value, and how many values wil there be. the best would be that a sheet open, and i could with the mouse show the field for the string and the field for the value(s).

since i have few hundred such formats, then upon opening a file, the software should compare its possible strings/fields with the one under examination. in case the is a fit, then extraction is automatic. but if there is no fit, then once again the datasheet should open itself, and allow me to choose the relevent field. a mouse operation would be fantastic here, and i was hoping somebody already has something done on similar topic.

to note that the datasheet can be a simple text file with no tab delimiting the string and the value (just a space or ':').

Hey

finally back to some LV programming, this time with an interresting challenge.

i have several large datasets to extract. the number of datasets is such, that i need a semi automated solution.

each dataset includes few thousand files.

some dataset are text files, and some are excel workbooks, including several sheets. this is the first time i deal with excel data extraction, therefore would be happy for some instructions.

the idea is this: look-up in the file a value of interest, and define its "position". Then, for all the files in this dataset the program will automatically extract this value. the way the prog should determine if a value is in the right field, is by its description with preceding string.

Everytime there is no match, i should be able to define a new look-up position.

At the end, i expect the program to pick up a file, and look the value related to several possible formats.

Any idea to give me a lead how to takle this?

edit: i will cross post it on the dark side as well

QUOTE(neB @ Mar 6 2008, 07:53 PM)

Now if I my memory would work as well when trying to solve the Schroedeger wave equation...

Ben

send me a PM, i'll try to help you . But dont forget to mention the boundary conditions and the surface potential which defines the matrix

QUOTE(T_Schott @ Feb 22 2008, 11:42 AM)

you can buy this from rsonline.de (german shop)

http://de.rs-online.com/web/search/searchB...amp;x=0&y=0

crelf: this one has the advantage of being adjustable, but stiff lamelles. with the simple rack, one always has problem fitting sma or smb connectors. however, much cheaper and easy to bend the lamelles (usefull to force entry... ).

note: i would never had expected a forum topic about rack fittings... LAVA is great!!

just to add feedback, maybe it will help solve the issue:

the type def resizing is a bug, from a user stand point. that is why strict type defs exist.

The actual configuration forces me to disconnect the 'original' cluster (the one displayed in the FP), from all the ones used in subvis or so. in order not to have such resising problems. that induces of course quite a bit of headache, since there is no "reconnect to type def".

i would love a pop up view on subvis + their diagram, especially from the project explorer.

QUOTE(_G_ @ Feb 19 2008, 06:49 PM)

As many of you may know, this book originally had readable diagrams and then a subsequent printing had diagrams which were blurry to the point of being useless.

I contacted Prentice-Hall and was told, rather unconvincingly, that the issue was cleared up. I wanted to buy several copies of this book for our group but am curious if anyone has bought it recently (say in the last year or so).

Thanks, Rick

the print has very bad quality. but i got with it the electronic version, and it is very well organised there. figures are much better, but not all at the adequate size.

QUOTE(i2dx @ Feb 9 2008, 09:59 AM)

sounds like you have some experience with such circuits?

A little bit. i use magnetic coils and high currents.

QUOTE

are you offering me a job? :laugh:

, you better call a real electronician if you are afraid, but it is not that difficult, if you follow all the datasheets. but the "directly connected to a cRIO" is a dont do at home stuff.

in general:

the IGBT should be switched using an optocoupler, even tough it necessite an external power supply. on the bright side, you probably can use same power supply to drive the IGBT (plus the one on the cRIO side of the connection). the IGBTs i buy generally are from Mitsuishi, and they do the job nicely. switching on should be digital, the IGBT should be cooled using a water cooled plate glued at the bottom (the IGBT eats up about 3V of voltage, independant on the current. you can see that it is fast reaching high temperatures). for switching off, the IGBT should always be fully protected by a varistor (put several in parallel, as they tend to die fast). for 20KHz, this should definitely not be a problem.

notes:

1) in general, it is much easier to modulate the current trough the current supply rather than the IGBT, and use the IGBT only as a switch. in this way, one avoids lots of troubles. altough limiting the capabilities, complex waveforms at very high frequencies cannot be achieved without completely taking in account the whole circuit ( due to induced fields and so), therefore most of the time the relatively slow response of the power supplies (order of ms) is enough for such modulations. on the other hand, IGBTs used as switched have proved their usefullness for example in hybrid cars (DC power supply to AC motors). the power supplies i like most are from DELTA. expensive but very reliable.

2) cool the IGBT!!!

3)the driving circuit for the IGBT is easy to build, and you should find an example circuit in the datasheet of the IGBT itself.

4)use varistors all around in your circuit. they are cheap and easy to plug everywhere: between the nodes of the power supply (check max voltage it can withhold), between the nodes of the IGBT (use a good margin voltage for breackdown - your circuit will probably not have too high an inductance, therefore you should not be too worried about longer switchoff times - but calculate to be sure).

5) for testing, drive your system at low current. you minimise risks to burning the IGBT to zero, and they are expensive stuff.

6) the whole thing will take you some time (actually quite a bit). if you dont expect to build too much of those, much better is to buy a finished solution!! when one think that a worker costs 6000Euro per month, plus material and long learning curve...

7) good luck! but arent you more of a Labview guy?

QUOTE(rtn1 @ Feb 8 2008, 10:31 AM)

Hey. I am trying to control 200 volts using PWM. I understand that DAQ boards that i know of cannot produce 200 volts so i would need a seperate DC power supply. The only way of turning on and off this 200 volt source using labview that i know of is a relay, but i am wondering if there is a relay fast enough to process the PWM. Is there any other way of varying a voltage as high as 200v using labview? Any information will be helpful. Thanks in advance.

my salt: this is not a LV question, much rather a hardware one. if you have little experience with relaying, better get the help of an electronician. MOSFETS, and especially IGBTs, are expensive and relatively much more complicated equipment than simple relays. but for your voltage and frequency range there is not much choice. for higher currents as already pointed out you have not much choice but a IGBT. be aware tough, that they require separate power supplys, and that they tend to break very easily if not handled with great care in designing your circuit. for example, if the induced magnetic field is high, then you can expect a 'backcurrent' at turn off of the IGBT, which could lead to a surge of voltage to very high values. IGBTs in general cannot handle more than a thousand volts or so, (not to mention health and risks to living organisms...), therefore should be protected with varistors. These in turn have a breakdown voltage proportional to the current, so you should also look into the datasheet of those and choose them carefully. They also induce a longer shut down time, (depending on max voltage, current and induced field), limiting the overall rate of switching.

to your consideration...

QUOTE(crelf @ Feb 3 2008, 05:14 PM)

Love it! It confirms that internet-based viral media can be a powerful marketing force.

thats it! i'm convinced!

QUOTE(crelf @ Feb 3 2008, 12:49 AM)

Git yee to the movies! Or a local microbrew! Or a jazz club!

i wish! with an expanding family this today one of my nicest dreams...you know, the ones that are almost achievable but you are just too tired to actually materialise them? (that and the lack of baby sitters...)

ho noo....

i was just today asking my wife when was the last time we went out in the evening...or when will we...

QUOTE(Neville D @ Jan 25 2008, 11:41 PM)

Why not just use Chart>right-click property>history? Is there anything wrong with using the easier way?

Well it is mainly my personal taste, and the way i document things: having a property node for a FP element with its name directly connected i good when i have relatively few such elements. however, in this particular code i have a FP that uses a tab control with several tens of elements. then, i group most of my elements into clusters (type def) that refer to a specific operation or stage in the UI utilisation. then, most of the time changing properties for the controls in the cluster as a whole has avdvantages, and can be treated by reference to a case structure inside a for loop.

in short - i got used to do it this way.

of course, once i actually need to get a strict reference specifier, i loose this advantage, since i need to go and find it directly from the control itself...

QUOTE(jhoskins @ Jan 25 2008, 08:38 PM)

If it is in a cluster then you will have to get the reference to the cluster. then use a property node to get the controls reference array. index the array to the proper control. (same as tab order in a cluster), then using another property node write an empty array to the value or to the history data.

or you could right click on the chart in question and select creat property node/ value or History data and wire an empty array to it.

i have no problem referencing the waveform. but i cant find the property to clear the chart. writing an empty arry doesnt do the tric (history data is kept in the waveform itself, and is not retrievable to my knowledge).