It crushes when the formula in a Formula Node is somewhat complicated.

I call outer Formula Node VIs using Call By Reference Node VI. This works well in general but for some VIs with a little complicated formulas. The system crushes while calling the VI repeatedly. In the attached files, Script1.vi goes well but Script0.vi doesn't. The difference between two is just that the expressions in the former are short (but equivalent essentially). Are there any rules or constraints here?
Attachments:
TestScript.zip ‏40 KB

Hi Randy,
Thanks for your answer.
I've raised one more question at the forum. I lastly attached a sample program for explaining the issue. I would greatly appreciate if you check the program at http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=5065000000080000008A6D0000&UCATEGORY_0=_49_%24_6_&UCATEGORY_S=0.
Michiro

Similar Messages

Using the Formula Node for PDA

I get a compile error when I use C code inside the formula node. Is it possible to use C Code inside the formula node for PDA applications? Do I have to include any file while building the executable for the PDA

Ok, I was able to successfully build an executable file without error. I attached the screen shots of your program in execution. Does this look like the desired result?
I'm confused as to why I can build and run the program on my machine. I have LabVIEW 7.0 and Windows XP. What version of Windows and LabVIEW are you using? Also, are you getting the error window when you try to build an executable or when you attempt to run the VIs within LabVIEW?
Regards,
-Joe-
Attachments:
tutor.JPG ‏100 KB
tutor2.JPG ‏122 KB
detector.JPG ‏46 KB

How to change content in the formula node of the current vi

Actually I want to give formula with array index.
My formula p=a[0]-30; But i couldnot give array index in the formula expression..
Please help me in this issue.

Muthu92 wrote:
Thank you for your reply. It is very useful for me. But i can't give conditional operator in that operator. It is showing error.
My Test cases
A[0]+A[1]>150
A[31]-50 <100.
If those are your exact statements, then they don't make sense in a formula node. You have to use them in an if-statement or some other type of control logic. This mimics text-based programming languages such as C... See here for instructions on formula node syntax: http://zone.ni.com/reference/en-XX/help/371361G-01/lvhowto/formula_node_syntax/
For instance, you COULD say something like:
**In this example, let A[0] == x, A[1] == y, A[31] == z**
if(x+y>150)
/* do something if this is true */
else if(z-50 < 100)
/* do something else */
EDIT:
It should also be noted that Variable Names MUST be lowercase!! I just discovered this
EDIT2:
I stand corrected. After trying to create an example and digging through the LabVIEW Help, I stumbled across this:
Differences between the Parser in the Mathematics VIs and the Formula Node
The parser in the Mathematics VIs supports all elements that Formula Nodes support with the following exceptions:
Variables—Only a, a0, ..., a9, ... z, z0, ..., z9, are valid.
Logical, conditional, inequality, equality—?:,, &&, !=, ==, <, >, <=, and >= are not valid.
Functions—atan2, max, min, mod, pow, rem, and sizeOfDim are not valid. You can use these functions in a Formula Node or use their corresponding LabVIEW functions.
So it DOES NOT seem like Eval Formula Node can do conditionals like you want. I would just implement them using a LabVIEW based algorithm after all. Trying to out smart the formula nodes to avoid simple LabVIEW code is just too much of a hassle
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If someone helped you out, please select their post as the solution and/or give them Kudos!

BB Desktop software crushes when the device is connected

Hi all
Each time i try the Blackberry desktop software it crushes when the device is connected . I tried instaling and reinstaling (using clen uninstall0 it to no avail . I checked the  Rim.Desktop.Exception log and i get this :
Date|Log Level|Thread ID|Module ID|Log ID|Message [2012-01-08 19:50:07.291]
19:50:50.320|FATAL|1|Exception|0|Fatal Error
System.InvalidOperationException: Unable to get the window handle for the 'RemoteWindowsMediaPlayer' control. Windowless ActiveX controls are not supported.
   at System.Windows.Forms.AxHost.EnsureWindowPresent()
   at System.Windows.Forms.AxHost.InPlaceActivate()
   at System.Windows.Forms.AxHost.TransitionUpTo(Int32 state)
   at System.Windows.Forms.AxHost.CreateHandle()
   at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
   at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
   at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
   at System.Windows.Forms.Control.CreateControl()
   at System.Windows.Forms.Control.WmShowWindow(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.ContainerControl.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.IntCreateWindowEx(Int32 dwExStyle, String lpszClassName, String
Can anyone please help?

I'm having the same problem. Installed windows 7 professional over windows 7 home preminu.
Only see USB device if it's plugged in at startup.

Diplaying some text when the formula value is negative

Hi all,
I am calculating the date difference using the formula diff= date1- date2.
My requirement is when the diff is negative it has to displayed as # or with some text but not as zero .
Regards

You can display some random number say 999999 instead of # or text.Is that feasible ?
As # and text cannot be used for key figures.
You can create a formula like :
( diff < 0 ) * 99999 + (diff >= 0 ) * diff
Hope this helps.

Computational Error when using if then formula in a block, when the formula

Hi all,
I am getting a computational error on one of my reports,
where i have created a new variable. The variable is an "if and
then" formula which uses the date variable. However if i leave the
date variable in the report block then the new variable is fine and
works. However due to the nature of the report we would like the
report to give a summary over a date range. In normal circumstances
i would be able to simply drag out the date variable from the report
block and it would create a summary. Unfortunatley in this instance
i get the dreaded "computational error". I know its due to the fact
that business objects requires the date variable present. Is there
any way around this...
I've seen some manual work arounds i.e table
properties and hide the date field, and then group header for each
category with totals and then table properties and select Fold so
that it shows the total (one for each product, rather one for each
day and each product). Just wandering if there is perhaps a more
efficient way around this. your help will be much appreciated.
Nandeep

I don't think it is possible to lock in the date and time using a formula. You could put NOW() in a cell, copy, and Edit Paste Formula Results where you want the result.
Or if you are "time stamping" a lot, you may find this Automator Service (Dropbox download) helpful. It puts a "Today" function (actually it should be named "Now" because it includes both date and time) in your Services menu like this:
Just doubleclick the .workflow package to install it. You may have to click "download anyway" in System Preferences > Privacy & Security.
If you want you can assign the service a keyboard shortcut in System Preferences here:
SG

Why do I receive Error -23088 when using the Eval Formula Node.vi (LV6.1)?

Hi,
I want to evaluate formulas like x=v>20; with that vi. When typing the
same formula into an normal Formula Node I get the correct answer. When
changing the formula into x=v+20; the eval Formula node.vi works fine.
But whenever I try to resolve a boolean function like that mentioned
above, I receive that f****n Error! Why this? What can I do? Is the Eval
... .vi less powerfull than the normal node?
Thanks for your help,
Daniel

Joel A wrote:
> I think the boolean (binary) ops are the only difference between the two nodes.  I pulled this from the help:
> Formula Node and Expression Node Functions
>
> The following list contains the names of the Formula Node and Expression Node functions, and their descriptions. Except for the binary functions, you also can use these functions with <a href="gmath.chm::/Parser_VIs.html" target="_blank">Formula VIs</a>. All function names must be lowercase. You also can use <a href="mk:@MSITStore:C:\Program%20Files\National%20Instruments\LabVIEW%208.0\help\lvhowto.chm::/Precedence_of_Operators_in.html" target="_blank">operators</a> and the pi constant in Formula and Expression Nodes.
> Start at the help above, and see if you can find any helpful information.
>  
>  
> J
Thanks for help,
I solved the problem by using the "Parse Arithmetic Expression.llb" from
examples. You can modify it and add the operators you need..

How can I increment the index of an array in a formula node?

Hi,
I need some help with the formula node. I need an array, that increment every iteration of the code in the formula node. I need it to save amplitudes.
I thought i could do this with i++; i is the variable for my index.
Martin
Solved!
Go to Solution.

Hello,
does it sound well to you ?
@+
Tinnitus
ps: sorry posts mixed
Message Edité par tinnitus le 12-15-2008 03:05 AM
CLAD / Labview 2011, Win Xp
Mission d'une semaine- à plusieurs mois laissez moi un MP...
RP et Midi-pyrénées .Km+++ si possibilité de télétravail
Kudos always accepted / Les petits clicks jaunes sont toujours appréciés
Don't forget to valid a good answer / pensez à valider une réponse correcte
Attachments:
inc_node.vi ‏6 KB

Does anyone know if there is a list of the functions/statements that can be used in the formula parsing (used in the VI Eval Formula String)? I

have figured out a few already (ln(x), log(x), x^y, sin(x), asin(x), sinh(x), asinh(x), sqrt(x), pi(x), exp(x) ) but a complete list would be very useful. At the moment I am trying to figure out if it can handle factorials (x!). Any ideas? I am using LV6i.

have figured out a few already (ln(x), log(x), x^y, sin(x), asin(x), sinh(x), asinh(x), sqrt(x), pi(x), exp(x) ) but a complete list would be very useful. At the moment I am trying to figure out if it can handle factorials (x!). Any ideas? I am using LV6i.Such a list is in Chapter 1 of the "G Math Toolkit Reference Manual". Please note that there are some differences to the formula node. Therefore, the help on the formula node lists some functions, that do not work with the Parser VIs.
You can get the G Math manual from: www.ni.com/manuals
Just search for "math".
Hope this helps!
Robert Buhrke, Systems Engineer
Contact: [email protected]

What is the square and x^3 function in formula node

Thanks.
Solved!
Go to Solution.

y = x**2;
y = x**3;
If you open the help window and hoved the mouse over the formula node you can click the details link and find all the functions and syntax.
MTO

I need in Formula Node to assign to the variable value 4000000000!!! What kind of variable it should be???

i've just tryed to write unsigned in32, but it does not understand 'unsogned'... But i need variable to be unsigned, because the max value = 4000000000... So, how can i solve this probleme???

Hi,
I don't see exactly what you're trying to do here.
Where do you want to assign the variable 4000000000 to? If you want it as an
input, just use a dbl, with only zeros behind the coma.
Note that an integer is a number without any decimals. An integer in LabVIEW
is this, but with an extra limitation that it can only be 32 bits... So a
dbl can be an integer.
If the input dbl is not an integer, use round, round to -inf or round to
+inf to make it one. This can also be done if the output needs to be an
integer.Inside the formula node floor(x), int(x), intrz(x) or ceil(x) can be
used to make integers.
I hope this is what you mean... I can't see any problems doing this.
Regards,
Wiebe.
"DrON" wrote in message
news:506500000008000000E
[email protected]..
> I need in Formula Node to assign to the variable value 4000000000!!!
> What kind of variable it should be???
>
> i've just tryed to write unsigned in32, but it does not understand
> 'unsogned'... But i need variable to be unsigned, because the max
> value = 4000000000... So, how can i solve this probleme???

How can I specify simple math like in a Formula Node but on the front panel?

If the Formula node had a "text" property, that would work for me, because I could limit my inputs and outputs to N floating-point numbers.
LabVIEW once had such a thing but it was in an add-on math library, and I don't remember what it was called.
Solved!
Go to Solution.

Thanks; that led me directly to what I was looking for. A combination of "Parse Formula String.vi" and "Eval Parsed Formula String.vi" works perfectly for me!

If-then statement in formula node

**Note - The attached file shows the current block diagram.
I have a formula node inside a for loop. Inside the formula node I am trying to program the if-then statement:
If T1<2.0E-5 OR T1>5.5E-4 THEN GOTO 3
U7=U7+V
I have 4 items I need help with:
(1) Is 'II' the correct operator for 'OR'?
(2) Is 'goto' an acceptable operator within LabVIEW?
(3) 'U7' is building a 1D array. How do I need to define it? Is it simply 'int U7'? Also, I will add an output value named 'U7' on the formula node wall with an indicator wired to it from outside the for loop.
(4) Is my use of the equal sign appropriate or do I need to use '=='?
Thanks for the help.
Philip
Attachments:
if-then_in_FN.jpg ‏18 KB

Thanks for the help. I went ahead and rewrote the program so I could omit the 'goto's. Another problem that I am having is that I want 2 statements for 1 assignment:
if (T1>=.002004 && T1<=.002584)
B1=U
A1=V;
I want to assign both B1 and A1 values when the above condition is true. I tried a comma between the U and A1 but it doesn't work as well. Should I define A1 and B1 separately? Or would this create problems?
if (T1>=.002004 && T1<=.002584)
B1=U;
if (T1>=.002004 && T1<=.002584)
A1=V;
Thanks,
Philip

Formula node

Hi everyone.
I have a problem with the formula node.
I want to calculate the following function:
Ux=xdot+Omegat*(y-y0)+thetax
where xdot, Omegat, y, thetax are all 1D arrays ( honestly these are waveforms but I convert these in arrays) while y0 is a constant. Also the output Ux has to be a 1D array.
When I implement the formula in the appropriate box I receive a message about
"array indexing indices".
For more information I link my .VI.
Some idea how to solve this task?
Second question:
Using the formula node is faster than realize all these operations in a
different way?
I ask it because I will need to include this .VI into 5
different "for loops"?
Thanks
matomato
Attachments:
formula node.vi ‏87 KB

Hi matomato,
fastest is usually to use LabView primitives! See attachment...
Edited: made another small change to your vi: changed y0 to DBL to avoid unneccessary datatype conversions!
Message Edited by GerdW on 02-27-2008 05:11 PM
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome
Attachments:
formula node1.vi ‏87 KB

Formula node uInt32 overflow

I'm having a weird behaviour in formula node. The overflow of unsigned integer operations simply doesn't match the results of standard LabVIEW blocks as shown in the attached picture.
How can I deal with this problem? I need the behaviour of the block diagram. I could not do a right logical shift in unsigned integers in block diagram, so I'm using formula node (I could not figure out how to do it because I can't negate a unsigned value).
I'm using LV2012SP1. Were there any changes in this behaviour in newer versions?
Thank you.

I found a problem in hexadecimal and octal numeric representations of the formula node. The picture illustrates the issue. Three variables are assigned with the same value but outputs different results.
The hex and octal representations only work for half range of the 32 bits unsigned integer. When the value assigned gets beyond this limit the variable receives zero. This doesn't happen with a decimal value neither with 8 bits variables. Seems the problem doesn't only happen with overflow operations.

It crushes when the formula in a Formula Node is somewhat complicated.

Similar Messages

Maybe you are looking for