Francois Normandin

I'm not getting information of devices on my system. Can some take a look and see what i'm doing wrong.

 

I'm not either. I've not succeeded in retrieving a handle the the proper DeviceInfo (and I won't have time to play with it since it's back to work tomorrow...) but here is a little tip: Use the GetLastError and FormatMessage functions from kernel32.dll. This way, you'll know what sort of problem you have.

It seems I've misled you with the datatypes I showed on my screenshot but I thought it was not important since those parameters are optional. The LPGUID typedef is a pointer to a GUID structure. Think of "struct" as a cluster in LabVIEW terminology. Hence, the datatype for GUID is something like this:

typedef struct _GUID {DWORD Data1; WORD Data2; WORD Data3; BYTE Data4[8]; } GUID;where for example this GUID: eeaf37d0-1963-47c4-aa48-72476db7cf49 would be represented by:DATA1 = EEAF37D0DATA2 = 1963DATA3 = 47C4DATA4 = {AA, 48, 72, 47, 6D, B7, CF, 49}

It is not trivial to get these to work in LabVIEW... The trick is to match the types and I personally find that frustrating sometimes!

In this case, I'm returned ERROR_INVALID_DATA. I'll leave it up to you to find a solution... But here's my Windows Error Extraction class if that can be of help. (Just input the error code from GetLastError() and Merge it to LV error cluster.

Download File:post-10515-1231128408.zip (LV 8.6)

Confirmed here (8.6).

The behavior is the same when you "Group" the decoration and boolean. It gets scattered (while maintaining Group status).

QUOTE (mattdl68 @ Jan 1 2009, 02:21 PM)

My problem is don't know how the parameters are configured.

HDEVINFO

SetupDiGetClassDevs(

IN LPGUID ClassGuid, OPTIONAL (how do I configure each of the parmteters in labview)

IN PCTSTR Enumerator, OPTIONAL

IN HWND hwndParent, OPTIONAL

IN DWORD Flags

);

See this link for commun typedefs. This will help you setup the DLL properly.

QUOTE (mattdl68 @ Jan 1 2009, 02:21 PM)

My problem is don't know how the parameters are configured.

HDEVINFO

SetupDiGetClassDevs(

IN LPGUID ClassGuid, OPTIONAL (how do I configure each of the parmteters in labview)

IN PCTSTR Enumerator, OPTIONAL

IN HWND hwndParent, OPTIONAL

IN DWORD Flags

);

See this link for commun typedefs. This will help you setup the DLL properly.

QUOTE (msaf @ Jan 2 2009, 05:41 PM)

Hello,

I need to save a list of times, in which the data is read by the data acquisition device, as a .txt or .xls file. Unfortunately, the data produced by the 'Get Date/Time' function is a string and can not be written in an .xls file. I can not append the time data in a .txt file to make a list.

I appreciate if you could help me with this.

Thanks.

You need to get a numeric instead of a string. Use the "Get Time/Date in Seconds" function of simply "Tick Count (ms)". See example below.

http://lavag.org/old_files/monthly_01_2009/post-10515-1230939142.png' target="_blank">

QUOTE (Kumaresh @ Dec 31 2008, 08:14 AM)

how to measure a 4 wire resistence by using PXI-4060 DMM card?....what is the max resitence can measure?....

To perform a 4-wire resistance measurement, you'll need more than a DMM: a current source and a DMM.

DMM's have typically a 6Mohm impedance. Some perform much better, but that comes at a high cost generally. I haven't looked at the PXI-4060's characteristics but the datasheet says 200Mohms, which is quite good compared to Agilent 34401A or Fluke.

QUOTE (crelf @ Dec 24 2008, 09:30 AM)

at least that will confirm if it's your the configuration (which I'm almost sure it is) or your software.

As do I.

Check out this video to help you test your camera's configuration.

QUOTE (Jim Kring @ Dec 23 2008, 10:55 AM)

The other champs are Buddy Haun (hat) and Albert Geven (beard). And, the NI guy on the far left is Todd Sierer.

You beat me to it...

If you have some magic image enhancement software: :ninja:

QUOTE (Irene_he @ Dec 23 2008, 01:52 AM)

Dear LAVA Members,

Holiday is approaching. I wish you all happy holiday and a prosperous brand new 2009!

(9>8, has to be good).

Irene

For all positive values of Planck length...

Yeap, happy holidays to LAVA's!

There must be two drivers available, one for your software and the generic IEEE1394 driver... As crelf pointed out, check in MAX and change the active driver to the generic one. (From what I can remember, you might have problems with your external software once you've changed it...)

I've got a hard time finding what I'm doing wrong to add my own LabVIEW instruments to MultiSim (10.1) and I'm wondering if there wouldn't be a version compatibility problem. I've opened one of the examples provided with MultiSim and saved it (LV 8.6) and now it doesn't work anymore, no changes to code whatsoever. I found out that MS10.0.1 required the LV instruments to be saved no later than LV8.2, but that doesn't seem to do it with MS10.1 and I can't find any specific notes on that on the dark side.

Has anyone encountered this problem before I call up NI?

QUOTE (AZoptics @ Dec 22 2008, 12:18 PM)

Hi,

I've only ben exposed to LabView for about a year now, and it's still rather new to me. I've been put in charge of re-writing a program in LabView 7.0 and I keep running into some problems with some IMAQ1394 sub vi's. The error always reads out "Invalid Session ID". Also, I traced the error back further and it says that there is an invalid file name for the camera that I'm trying to use. I've tried researching this problem, and haven't come up with many answers. The camera ID is the same in this program as in another working program on the computer. I really could use some help trying to figure out what's going on. Thanks.

You should post some VIs or screenshots of your work for us to help.

QUOTE (SaNoSuke @ Dec 22 2008, 05:05 AM)

thanx alot guys for wat u said .......but as a strating ....i was trying to control it with pulse generation and send it throught the interface board to labview,i will show u the code i did but still facing some problems in accuracy...

one more question...is there a diffrence between controlling 6-wires and 4-wires motors??i mean in the code?and which one is easier to control?

and everytime am trying to use the DAQassis is not working cuz i dont have the card.....so can i install a vitual card so i could use it at home ?

I always refered to this http://www.cs.uiowa.edu/~jones/step/' rel='nofollow' target="_blank">website when I was confused between types of stepper motors.

QUOTE (Minh Pham @ Dec 21 2008, 05:39 PM)

Hi guys,

I just wondering that is anyone in here success capturing the event (eg. mouse down or double click) from an element within an array. (index returned prefered)

As LabVIEW doesnt have this option, it does have the Mouse Co-ordinate values returned which can be used but it is not the optimal way of

doing this i guess, you still have to figure out which item within the array is clicked/double-clicked and return the index so you can process a certain task

for that item (eg. change the value, or pop-up msg).

Any help is appreciated,

Regards,

If you don't worry about datatype (i.e if you use strings), you could use a listbox. Listboxes have a method "Point to Row" that inputs the mouse coordinates and outputs index. As far as I know, I don't think Arrays have a method to do that.

Otherwise, if all your array elements are unique, you could return the array element (variant), convert it and scan the original array to get the index. But as mentioned, it works only if all values of your array are unique.

QUOTE (BobHamburger @ Dec 21 2008, 09:19 AM)

The reason that all electronic devices work in the first place is that they contain magic smoke. The magic smoke makes everything function. We know that this theory is correct, because when the magic smoke escapes, the device doesn't work any more.

And because of the second law of thermodynamics, it costs more energy to try to put back the magic smoke inside than to just buy a new one...

QUOTE (GraemeJ @ Dec 16 2008, 06:22 PM)

Is it possible to have a number of tab pages enabled simultaneouly, and then programmatically bring any one of then to the front?

Regards,

GraemeJ

I'm not sure what you mean by "enabled simultaneously".

You can select the page to display simply by turning your Tab Icon into an indicator, or setting "Value" property to desired page if it's a control.

QUOTE (BrokenArrow @ Dec 16 2008, 02:12 PM)

:beer: :beer: :beer:

Maybe we should all chip in for Antoine...

merci Antoine :thumbup:

QUOTE (Antoine Châlons @ Dec 16 2008, 09:45 AM)

I was talking about methods for Pages[].

The only methods for I have for a Page are these :

Sorry...

I get some more methods from the Scripting Workbench: (But not much really...)

QUOTE (Milchbilch @ Dec 16 2008, 10:52 AM)

Hmmm... with "Get LV Class Default Value.vi" I don't think that I can create a new object of e.g. type ClassA. I only read the standard values, don't I.

Or is there a way to get a reference of each object that was created that way? This is what I really need.

The same kind of reference I get like when I rightclick a control and create a reference to that control element.

Stefan

Using the "Get LV Class Default Value.vi" will create a new instance of your class. You can store a reference to this instance and refer to it elsewhere. But that's a tricky design: make sure you don't disrupt your dataflow... (Personally, I don't like this design: I think it's dangerously hard to debug especially if you start creating multiple instances. You might run into data collision pretty soon.)

http://lavag.org/old_files/monthly_12_2008/post-10515-1229446300.png' target="_blank">

Hi Antoine,

You don't require scripting for these properties.

QUOTE (Milchbilch @ Dec 16 2008, 04:25 AM)

But instead of this "manual reference creation" can I create references to objects of type "ClassA" by using something like an

"Open class reference.vi" and typecast it to any of my classes?

Just like the way like I can create VI References using "Open Vi Reference.vi"

Check out the "Cluster, Class & Variant Palette". You'll be interrested by these:

http://lavag.org/old_files/monthly_12_2008/post-10515-1229436362.png' target="_blank">

QUOTE (jdunham @ Dec 13 2008, 08:08 PM)

I didn't see where anyone suggested looping a string with array subset. I'm not sure why a string would be used at all. crelf stored the patterns in a spreadsheet, but it seemed like he was doing that for lack of a better idea. Presumably the patterns would be loaded from a file just once, so speed wouldn't matter, but chris didn't really provide enough details.

The most efficient way is to store the pattern and the mask is to pack the booleans into integers. The pattern was 128 bits, so you could use four U32s for each pattern (and 4 more for the mask), but you're probably right that integers or booleans are fast enough, .

Instruments usually send a string, which you need to process. That's what I gathered from Chris' post:

QUOTE (crelf @ Dec 12 2008, 05:28 PM)

This is the reason I think any fast implementation of the masking as you proposed should start with a string and not with a boolean array.

Don't you guys think that converting the string to boolean array is the real bottleneck here???

All implementations of arrays/matrices and case structures will be fast enough, but I would bet that "Convert String to Byte Array" is faster than looping a string with "array subset" to extract the booleans. So if one must stream the instrument status bytes as fast as possible, then it's the string conversion that would concern me. :2cents:

Using Byte Array Conversion will get you there quite fast...