Thanks for a fast reply with relevant information! :)
I think using a history buffer and have one graph will be to slow. The
satellite will be active for 6 - 8 hours, and towards the end of that
time, I think (I don't know) that the time it would take to read in
the buffer and then display the
Gerd,
Why not just add up the complex fft's of the various segments prior to
computing the magnitude and phase. Works every time.
Sanjay Gupta
+-+
+ Chief Scientific Officer Former Head Phones:0512-2597830 (Off)+
+
I believe that opening the old VI's and re-saving them in LV 4 would
also work. If you don't have LV4 or 5 then a conversion kit for old
VI's is supposedly available from NI.
You might be able to find a workaround for problem (2) by temporarily
moving some of the problem VI's out of where they
If the message transmitted by your sensor is always terminated by a
specific character, e.g. CR or LF, just enable that as the VISA
termination character for serial reads and set a timeout that is a bit
longer than the sensor interval, e.g. 2-3 times as long. Use a VISA
Read function and wire a
System Configuration:
LabView 6.02
Windows NT 4.0
Pentium III 800 MHZ dual CPU, 256 Mbytes
PXI chassi
Problem:
My LabView application encounters two intermittent problems while
printing. A printer is directly connected to the system thru the
printer port.
The first problem occurs in the serial
It works as I anticipated. This is the answer. Just out of curiosity
how would you programmatically control the order. I think turning the
order off will use property settings of contorls to false. To program
the order of keyfocus I need to know what user is typing and whenever
tab is pressed I
The only difference is that the 6.1 version that creates an x array is
just called Get Waveform Time Array.
Have you test your vi over long period of time? Did you see the
memory increased steadly? Or does it go to a level and then drop back
to a lower level?
From what I tested, it seems the memory does not increase all the
time. The memory usage increased to a certain amount and then
maintain that
as tu essay=E9 de peser sur pause une fois qu'il est pris dans une loop,
et ensuite tu peux faire avancer le program step by step.
I am assembling a system and need to be able to control both a newport
motion controller (already has LV drivers, so I am sure that's all
set) as well as take load data from a Sensotec load cell controller -
the controller uses a serial connection for data transfer. Can I use
labview to readily
Hello
Here's my problem. DLL looked always magic to me, so I tried to work
with them to see how it works. I wrote a DLL in Labwindow/CVI 6.0 and
my first fonction had the following prototype
extern int __cdecl MyDLL_Init (int In1,char *Out2);
I did'nt exactly know why using a C type
as tu essay=E9 via le ftp!
Based on the data you included in your question, I would guess your
(A) analyzer is set to return data in ASCII format while your (B)
analyzer is set to return data in binary format. Typically data
encoding format is settable on many instrument. Therefore, you can set
(B) to return data in the
You can see the classes and books NI offers at the a
href=http://www.ni.com/training/;customer education page/a.
Regarding your string parsing...
Maybe I don't understand your protocol, but it looks to me like it's
just a simple query/response protocol. So I'm not sure what you mean
when you talk about a continuous stream of data.
It seems like you'd just send ?Temperature1\n and immediately do a
VISA
I'm having the same problem. Seems that if you have more than 90
parameters, the General LS Linear Fit.vi returns error -20021. Seems
like there is an unstated maximum array size for the GenLSFit_head
function in the DLL the vi calls.
Did you ever find a workaround?
It depends on how you want your sub-vis to behave.
Any sub-vi will follow what is set in its execution properties. So if
it=92s set for reentrant operation, it will run that way. If it=92s not
set for reentrant operation, the same instance of the VI will be used
regardless of what is calling it.
Just recently, we've been trying to upgrade our testers to an Analogic
Digitizer which uses Dll files for programming. So we've modified our
test code with the appropriate library function calls and have tried
to run the software via our labview test executive.
It seems that when we run the new
When loading opening a new test sequence in labview, the software may
go off and search for a dll that may be located in another unexpected
directory. Usually, the software will find the file before you can
determine which file it was searching for and what path it expected to
find the it and
Ruud,
Thank you for contacting National Instruments.
The problem does in fact have to do with the very small values of Y.
As you mentioned, the solution is to scale the Y values, perhaps by
multiplying them by 10^+8. The following link will take you to a
knowledge base article that will give
The only way to get meaningful phase is to start your acquisition at the
same phase for every segment. An example of this would be an encoder
pulse. If each acquisition starts at a once per rev pulse from the
encoder, they will all have the same phase components. Another
possibility is doing
Hi,
Yes, you can create a CIN on Mac OS X. You can find more information
on it in the a
href=http://digital.ni.com/manuals.nsf/websearch/8D930295FFBF9F7686256D2C00624728?OpenDocumentnode=132100_US;Using
External Code in LabVIEW/a manual pages 3-10 to 3-12.
I hope this helps.
Feroz
National
At 16:19 +0530 02/04/2004, Dr Sanjay Gupta wrote:
Gerd,
Why not just add up the complex fft's of the various segments prior to
computing the magnitude and phase. Works every time.
Works differently. That is a vector addition. For a varying phase it will reduce
your signal. For overlapping
want to achieve synchronous Bi directional Communication in a client
server setup using tcp ip .
The client sends some data to the server and immediately start waiting
for an acknowledgement from the server. now, how do i ensure that the
client reads the acknowledge ment and not the data that it
The driver comes with a complete set of functions and several high
level examples that incorporate them. There's one called HP34970A
Advanced Scan Example that will take voltage and/or resistance
measurments from a single scan list. It is easily modified to take
other measurments. There's another
Sudhir,
This is an expected behavior with strictly typedef ring constants.
Instead of menu rings, you will want to use enums.
A Strict typedef keeps its cosmetic information on the front panel but
not on the Block Diagram. The type of the ring does not depend upon
its strings - like it does with
John,
Thank you for contacting National Instruments.
To answer your first question, whether it is better to wire a URL or
reference into a DataSocket Read/Write depends on your application.
When you are going to be writing or reading multiple times to the same
connection (such as using a loop),
Very Slick. Thanks for the indepth reply. It certainly has helped.
I've just been playing it safe and closing all references. It was
indeed the creation of a bigger badder VI in which I came to wonder
about this. Thanks for clearifying.
Steve
Don,
Thanks for the IMAQ examples. What I am finding is that if you drag the
property node into another blank VI then drag the reference to the blank VI
front panel – problems occur:
1. The reference does not show as an IMAQ reference but a odd looking thing
with a red x “PlugInContol
Can anyone help me pass variables from my VI into teststand to run the
pass/fail test? I'm able to get my VI to run but cannot get the info
out of my VI and into teststand after the VI runs. How do I do this?
How do I also pass that info into the pass/fail test? Any other
teststand tips would
I've just been playing it safe and closing all references
Good go! Someone will benefit by this appraoch. It may even be you.
Thanks for the kind words.
Ben
a
href=http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101RPAGEID=261HRedirected=TrueHUserId=101_3529RFORMNUMBER=6;Ben
Rayner/a
a
I just had a thought (don't everyone cringe at once)...
You could change the text on the button programmatically using
property nodes and then when the button was pressed, read the button
text to see which state it was in. A little clunky but it should
work.
There are other, better ways of doing
I don't really see a need for anything else for your application. If
you are using a non-NI driver to acquire from the image, you should be
getting a 2D array from the camera. If not, you should be able to
easily convert it to a 2D array. The summing operations are standard
array manipulation.
I want to use a control to subscribe to value of a modbus register
through datasocket and pass the present register value to other
functions. I found that after subscribing, the control shows the
present register's value but pass the previous value to others instead
of current value. When I put
You said that the robot arm came with a driver. Typically this is DLL.
I'm assuming that this works but you want to integrate control of the
arm with a LabVIEW program. Hopefully the vendor can provide and API
(Application Program Interface) that describes the functions in the
DLL. The DLL would
Hi Brian and thanks for your feedback.
A few comments:
I'm tagging the data, because I want to be able to sample and send
in a loop from the satellite side, without querying for the data. But
I also want to be able to query specifically for data manually. I
don't know what I will end up doing in
No.
When the server receives requests from the clients, does it really
reply in parallell, or does it handle the requests sequencially?
If the latter, improve the performance by dynamically creating
connection handlers that process requests from each client
individually.
Compression is another thing
Use different compile scripts for different versions of your
program--what needs to be different in the compile script is the
registry key the installer is looking for. When an install package
finds that the key is already registered it will try and do the
uninstall, which is really handy if you
So it sounds like you want to send back a sequence of two-byte binary
data samples. Thus, you'll use the Type Cast function.
(When I talked about ASCII, I meant that encoded the value 142 as
three ASCII characters, '1', '4' and '2'. It sounds like you are not
going to encode your data this
In LabVIEW, there are TestStand Native VI's for:
Get Boolean, Set Boolean,
Get String Set String
Get Number, Set Number
Get Variant, Set Variant etc.
These are all available in the scalar, or array variety,
(and I've actually created multi-dimensional array VI's also.)
and these are available
I don't see any benefit to averaging parts of the signal. If you
average within a single revolution, you will lose your phase
information. There is no benefit of averaging sections of repeated
signals either. Just do a large FFT for each revolution and average
them.
FYI, you could average the
The benefits are that you can see the signal change during the 120 second acquisition
time. You could see a 200 hz signal oscillate back and forth for example. This is
the approach taken by the JTFA (joint time frequency analysis) toolkit. They use
gabor spectrograms that take gaussian
Hi Jean-Pierre;
I had to look for this particular camera (photometrics 300). I did not spend much time but it seems to me that the camera is made
by Roperscientific and they also provide the frame grabber (PCI bus). By the sound of it, I guess the camera is RS170 and most probably
has some
As I understand it a version of LabVIEW can always(?) open a VI written with
an earlier LV version but the converse is not true.
If you have access to LV7 you can try 'Save with Options' to save those LV7
VIs as LV6.1 VIs. Sometimes this causes errors though...
Probably the better option is to
I put tens of cursors on X-Y graph using property node. Also. I used
the names of the cursors as some indicators. Is there a way to decide
the position of the cursor name? e.g., like using the property node.
Presently, I adjust the position menually one by one.
I am not talking about the position
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