.5 precission

I am a LabView newbie. I am using a hall effect sensor to find RPM. I set up my program to read out rev per second and I then multiply it by 60 to get the RPM. I am only getting returns of rps in incruments of 0.5 (I.E. 0.5 rps, 1 rps, 1.5 rps, 2.5 rps, ect......). What can I do to get more precision? Thanks.

Hi Bryant,
how many pulses per revolution does your sensor count?
Example: With two pulses per rev you will be able to measure rotation speed in steps of 0.5rps (when you take a sample each second) - there are no more pulses to count!
Again: Please provide more details about your sensor AND your program to get reasonable answers!
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

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Loss of precission with Doubles

My program does not like this, it says that I am loosing precission.
Both aspects are doubles, and it wants int. Why? (What's the difference between a double and a float?)
x = M.get(0,n) * ((Double)V.get(n)).doubleValue();
y = M.get(0,n) * ((Double)V.get(n)).doubleValue();
z = M.get(0,n) * ((Double)V.get(n)).doubleValue();

it wants int. Why?Probably because you've declaredint x, y, z;The way to deal with this isx = (int) (M.get(0,n) * ((Double)V.get(n)).doubleValue());>> What's the difference between a double and a float?
A double is more precise (64 bits versus 32 - http://java.sun.com/docs/books/tutorial/java/nutsandbolts/datatypes.html).
Kind regards,
Levi

Precission error with double 32668.6536

I have found something really odd adding two double values that add up to 32668.6536.
Instead of getting this double Im getting 32669.653599999998.
I cant think of a good reaso why the Java is doing this wild conversion. Any tips would be appreciated.
This is some sample code to replicate the problem. Ive tested it with JRE 1.4 and 1.6. I've also tested it with different double values that add up to 32668.6536 and it always fails.
public class DoubleAdd {
     public static void main(String[] args) {
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Gonso

PhHein wrote:
[SOME THINGS YOU SHOULD KNOW ABOUT FLOATING-POINT ARITHMETIC|http://java.sun.com/developer/JDCTechTips/2003/tt0204.html#2]
[What Every Computer Scientist Should Know About Floating-Point Arithmetic|http://docs.sun.com/source/806-3568/ncg_goldberg.html]
[Another good (slightly simpler) FP explanation|http://mindprod.com/jgloss/floatingpoint.html]
None of those explain why 32668.6536 + 1.1 is not even close to 32668.6536. But reply number 1 explains it perfectly!

Java and Numbers precission

Hi all.
I've found java does not treat numbers as I expected. For instance, if I write the code:
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public static void main(String[] args) {
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Has anyone found the same problem, is there an easy way to solve it without doing the explicit cast?
Thanks all.

A few weeks? LOL.I meant @ these forums.I know. That's what made me giggle. It's been posted on the forum for at least the past three years or so...

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Lenovo G550 Wi-Fi driver complaint and Windows 8.1 porting

Hello!
It's my first message on this board and I hope that I've got the right place to post in, as I've seen other subjects regarding the g550 on this board.
I've read the threads regarding using Windows 8 and it's drivers, and also the problems with the wi-fi driver - it's incapability of delivering good service - problems with a "weak signal".
Let me put it this way:
1. Right now I'm running Windows 7 64-bit and as my wi-fi driver I use the one the system provided when I installed it, that is :
So far, this is the best wi-fi driver available, which gets me the best network discovery( I see about 10 available wi-fi networks using this).
2. When installing the driver provided on the Lenovo Driver Site, which is broadcom 32-bit/64-bit combined driver, the number of networks which I can connect to via wi-fi decreases from 10 to only 2 networks, one of them being from my nearby router! This is inacceptable in my opinion! Now, the network speed may not differ to much, but the driver clearly lacks some functionality, since it can only see 2 instead of 10 networks - from the same location!
Now, for Windows 7 x64 things are good, I just stick to the windows provided driver ( 4.176.75.21) and I can use the wi-fi with no problems everywhere, at a good rate of functionality and performance!
My problems lie right now when changing to Windows 8 64-bit version, more precissely 8.1. I have done some experiments with this, and aside from the wi-fi problem, which I can no longer correct, all seems to be fine and I am quite happy with how my sistem runs on win8 64-bit.
The problem:
a) When running with the Win8 provided driver, the networks are few, just as using the lenovo driver, or even worse - only one network available - that from my router - located 100cm near my laptop! No other networks available... VERY BAD.
b) When installing the same win7 32/64 bit driver on win8, which actually works without compatibility problems - I get the same results as installing on the windows 7 configuration: 2 networks present, from the same location.
I have read on the forums, that it may be a chance that lenovo will provide windows 8 drivers for g550, but if they work the same as the current drivers for win7, they will be of no use, at the rate of performance provided. Can someone do something about this, i.e. provide better drivers, look into this problem?
I also tried to trick win8 and port the win7 64 driver to windows 8, by extracting the driver from the iso file or from windows 7 installed driver location ( got an .inf and a .sys file) but finally, I don't manage to install it in Windows 8, even with the "Have Disk..." option, where it ultimately tells me that it isn't a win8 64-bit supported driver. (No signed driver problems or messages appearing).
Now, as a solution for this, I would appreciate if someone could reccomend me one of the following:
1) either a way to make the lenovo driver work better, to configure it somehow, or to provide another driver for win 7-64 that also can be run on win 8 ( which it should be), that has good performance
2) provide me with a modality to "port" the current win7 driver which currently works the best with my Broadcom wi-fi to windows 8.1 64-bit.
Thanks for following this!
Solved!
Go to Solution.

Ok, I have solved my problems, this topic may be closed, as far as I'm concerned.
I will leave here the method in which I acted, so that any other person who faces the same problem will be aided by this guide.
Here is what I've done:
1) Ported the wireless driver from windows7 - that came on the original dvd - copied three files: two .inf files and one sys file, I think - can't remember exactly. Anyway, you can use some driver export software and select your driver and it will automatically detect and preserve the needed driver files. I have the files saved and if someone needs them, pm me, and I will tell you which files they are exactly, or send them.
2) Once I had the drivers from win7, I got into my windows 8.1 install, and accessed the "Advanced Startup Options", which has an option available to select some special features on the next restart -> you click on restart, and then the advanced features appear.
3) Select the 'disable driver signature verification' from the advanced startup options, once they show up, after the restat. This is needed in order to not get errors which won't allow you to install the win7 driver.
4) Just go to device manager, update driver, have disk option, select your .inf and there you go, just some prompts about the driver's lack of a signature, and you're ready, you can install the driver with no problem.
In my case, it worked perfectly!
I also did this with other win7 drivers, and it also worked.
Tip:
If you have problems and the drivers still don't work, check the .inf file, it may need some modifications.
See if it has an NTAMD4 6.2 section( that is for win8) and if it doesn't, or if that section contains no lines, just create it or update it by pasting the same lines that you see under the 6.0 or 6.1 sections also to the 6.2 section. Then, the have disk method will work, for installing your desired driver under windows 8.1.
I think this may be helpful for a lot of situations, not only for this specific driver and laptop model, but for most driver compatibility isssues users find.

In the Account Analysis Report Payables, currency precissions are not refle

Hi All,
In the Account Analysis Report Payables, currency precissions are not reflected propely.
The functional currency is KWD (Precission - 3). In the standard report (Account Analsyis Report) parables application, the output is shown in 2 decimals. The output should be shown in 3 precisions.
Regards,
Raju.

Some how the rtf (XLAAAR01) is not looking at the currency precision.
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By
Vamsi

Digitizer stylus support Yoga 13

I'm using the Yoga 13 for about 2 weeks now and I'm very happy with the device!
Does the Yoga have digitizer stylus support?
And can you recommend a stylus for the Yoga?
Thanks
Bmelk

I am starting to like my computer but I would like a bit more precission with the touch screen.
I know Lenovo makes a stylus for their ultrabooks and i wonder if someone from technical support would know if it works on the Yoga series. OR Is there are any stylus that could try.
Something like this ?
http://shop.lenovo.com/SEUILibrary/controller/e/web/LenovoPortal/en_US/integration.workflowroductDis...

Conversion or Casting................

Hi
I think i got a superb question.:)Let me explain u first.
Widening Conversion:::
A conversion that accommodate wider range of values than the original type.e.g.,
int in=25;
double d=in; //is legal
because int in is 32 bit and double d is 64 bit.
int ---> double
My Question:::
According to defination of Conversion , how it is possible to assign long value to float with out casting???
long lng=10;
float fl=lng;//it is legal. why????
because long is 64 bit and float is 32 bit.
Is there any Duke $ for a superb question. lmao :)
Thank you
Jafery

I think it's not really only a memory problem.
In "int"-like types the information is stored usign directly binary coding:
00000000 = 0, 00000001 = 1, 00000010 = 2, 00000011 = 3, ...
whereas in "float"-like types it's much more complex:
what you keep in your memory are, in fact, two numbers.
One of them is an exponent (x), the other a multiplication constant (c). Your number is constructed as follows:
c. exp(x), where exp(x) returns e^x (e = 2.718... I'm sure you've seen this number before)
Of course, ideally c (but not necessarily x) should be also a real number (otherwise you loose a possibility of unlimited precission), but it is not possible (computers are discrete machines). For x and c binary coding ("int"-like) is used (I used to know the exact algorithm. I think 0<=c<1, ... something like 0.00111011110011 - quite funny, isn't it?
and x is 8bit signed int - at least for float)
If you start to think deeply about it, the conversion to floats can never be 100%ly precise. It is the reason why comparing some calculated floats to a constant/variable may fail:
Ex. square equation: (x-x0)^2 + (y-y0)^2 = r^2 will never work, what you have to do is
(x-x0)^2 + (y-y0)^2 - r^2 < delta)

What is the best way to execute code at a specific time?

Hello,
I have a problem. I need to execute some code at a specific time: subVI A should run at e.g. 2 seconds (after start) and stop at 3.5 seconds and subVI B should execute at 3.5 seconds until 5 s. The user can choose the time points. It could also be that subVI B has to execute before subVI A or at the same time.
Time precission is not important +/- 20 ms is ok.
I have implemented it like that: In a loop (period time approx. 20ms) I query if the timeframe has come and then the subVI will be executed.
See attached picture.
I don't believe that this is an economic way. It will produce high CPU load. How can I do it better?
Greetings Johannes
Using LabVIEW 7.1 and 2009 recently
Attachments:
Timeframe.PNG ‏9 KB

@HaD
Something like this?
Johannes
LabVIEW 7.1 (!)
Greetings Johannes
Using LabVIEW 7.1 and 2009 recently
Attachments:
Timeframe.vi ‏33 KB

Controling Position and Velocity of trolley

Hey,
I am working on an application for a engineering design project that requires me to control the position and velocity of a trolley on a linear track.
I have done some work in LabWindows before controlling the speed and position of a linear movement but am having some troubles shifting my knowledge from a small application to what I am working on now. This is what my plan is; I currently have a motor (DC 24V 88A), String potentiometer to determine linear distance travelled (there was risk of slip and need of high precission), sufficiently sized power supply and BNC-2110 DAQ.
My plan (which I am looking for some feedback on ... no pun intended) is to use LabView to create a PWM (which has already been done) to control the speed of the motor via the counter turning on and off a power mosfet completing the Motor's circuit. By varying the time on and off I hope to control the speed.
After this has been completed I hope to hook up my string potentiometer to the Trolley and see how it's position changes over time (i.e. determine the speed at which the trolley is moving at for a variety of different % time on and off). This will act as an open loop test, which I was hoping to then figure out a practical transfer function for the motion of the trolley and then somehow use the String Pot as a feedback sensor to complete the loop and create a PI controller. I am having a hard time wrapping my mind around how I am suppose to put the later bit into practice. It all sounds fine on paper but actually approaching an implementation of this idea is boggling my mind.
Any input or pointers would be greatly appreciated. Am I on the right track or am I looking at something completly wrong... being a student I guess I don't know exactly how things are done in practice in industry, just what is written in books so any help would greatly appreciated.
Thanks!
Mac

Mac,
starting with an open loop system, determining the transfer function and designing the control algorithm is a reasonable approach albeit a little bit academic.
A more empiric approach is tuning the closed loop motion control system by means of test functions like white noise or a setpoint step. Here you can find some information about tuning a motion control system by analyzing the step response of the closed loop system (Please note, that this document refers to NI motion control boards, but the general approach of the tuning process is universal).
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If there is any kind of campus license of NI-Software available at your university, all the required software components should be already available for you.
Last but not least here are some considerations about the power circuitry. You have suggested to use a PWM signal that controls a single mosfet. This approach is not feasible in most applications, as it doesn't allow you to control the position and the speed of the motor accurately. To do this, you need to be able to drive the motor in both directions. You could do this by using an H-bridge circuitry, but this requires some more considerations when designing the control algorithm. In fact in most cases you would work with two cascaded control loops. The inner control loop is the current control loop, that generates the signals for the H-bridge, while the outer control loop is the position/velocity control loop.
Depending on the focus of your project, you may also consider using a commercial motion drive that provides the power circuitry and the current control loop. Those devices typically provide a +/- 10 V input for an external control signal that is provided by the outer control loop.
I hope this information provides some ideas to getting started.
Kind regards,
Jochen Klier
National Instruments

Can you user a track pad and magic mouse together

is this possible or does it cause some kind of problem?

You can use it with no problems, for example, you can use the mouse for precission tasks such as video editing and the trackpad for multitouch gestures

Bar code in LIV

Hi,
What is the relavance / significance of bar code entry in Logistics invoice verification.
What are the basic configurations needed for this.
Thanks,
Regards
Raghavendra

Hi,
In order to get the barcode printed, the barcode printer has to be present.
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In the print preview you can able to see the barcode as it just shows the normal bars not the ones with the exact precission.
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Cheers,
Simha.

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Hi,
I am working on an image-processingtool over 4 month and i am a little annoyed by
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Try to load an image ... convert this to an gray-image and then do some operations onto
this image under the restriction, that the values of each pixel should be minimal 16bits long.
I found each class i should use to create such an buffered image. I do so ... but the result is
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I described was not the best sign. I don't got the time to read books about color models, sample models etc.
to write an app which should do "only simple edge detecting ops".
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As I remember Studio4 place resource files under
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How to Print the definition of a Configuration?

Hi,
Created successfully a Configuration using the Configuration Wizard of the Repository Object Manager.
But can you please explain how we can print a report with the version details of this configuration?
regards,
ralpf.

Hi ,
I dont think in Floating point u can able to go for the decimal point display as it is for the minimum precission display..
Define the variable as the 'packed' type and then u can able to define the decimal point...
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