BCH Encoder Labview

Hello,
i have a problem. I need a Channel Coding for a 56 Bit Bitstream. The code is a modified BCH-Code (63,56. My generator polynom is x^7+x^6+x^2+x^0.
I have the NI Modulation Toolkit, but it dosnt help. In the MT BHC Encoder.vi i cant adjust the generatorpolynom and use the (63,56).
Has anyone an idee or an example for me?
thanks

Hi,
the MT BHC.vi uses the order m to choose a polynomial from a table in a subvi inside MT BHC.vi.
From outside it is not possible to specify a custom polynomial, so you could try to change is inside, but
I cannot tell what exactly happens there.
Marco Brauner NIG

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DAQ device for linear encoder & labview 7.0

Ok, I am in a bit of a bind, so the quicker the response the better =). I currently have Labview 7.0, and am needing to read the pulses of a MicroE hi-res encoder. I know I am in need of a DAQ device, so I just want to know which one would be the best (cost-effective & easy to manipulate with Labview). Also, I need three analog inputs as well. Preferably the range of the analog inputs would be 0-10 volts (well, preferably 0-10mv, but that is unikely). I am very unfamiliar with programming Labview, but will learn what I need .
Thank you VERY much!

Hello heepofajeep,
I would highly recommend you go with an M-Series Mulitfunciton DAQ Device for this application. The two counter channels on these devices have expanded support for two phase relative linear and angular encoders, compared to older E Series devices. In addition, these devices are capable of performing analog input, analog output, and digital I/O operations. They contain a minimum of 16 analog input lines, with a programmable gain amplifier that will allow you to programmatically set the range anywhere as large as +/-10V to +/-0.1V in order to take full advantage of the resolution of the ADC on the device. These devices can be programmed in LabVIEW 7.0 or later with the NI-DAQmx driver, and there is the DAQ Assistant and many great example programs for getting up and running with your application quickly.
I hope this information helps and let us know if you have any further questions.
Regards,
Travis G.
Applications Engineering
National Instruments
www.ni.com/support
Message Edited by Travis G. on 08-18-2006 04:55 PM

Generating BCH Codes for Forward Error Correction

Has anybody created VIs for generating BCH (Bose-Chaudhuri-Hochquenghem) error correction codes?
I need to generate the codes for a 16 bit data packet.
I've found samples in C on the web (http://www.eccpage.com/) but nothing in LV.
Thanks,
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I hate to bump a topic that is over 6 years old, but I am in need of a simple BCH encoding algorithm and do not have the toolbox which provides this. I only need the encoding algorithm so I am hoping to implement this .VI posted here.
I have slightly altered the cleaned up version that was posted to have the inputs/outputs in a format that I expect, but I am worried that it is not correctly calculating the BCH code. This is my first time working with BCH codes, but I need to implement the CCSDS version using n = 63, k = 56 7-bit BCH code with generator polynomial G(x) = x^7 + x^6 + x^2 + 1.
I think when using 0xC5C5C5C5C5C5C5 as my input message the 7 bit BCH is supposed to be 0x43, but I am getting 0x00. Could someone with more experience than me see if I did something obviously wrong? Or know of a way to validate a BCH encoding algorithm, so I know if what I did was correct. I attached my modeified .vi. Thanks!
Attachments:
BCH_3.vi ‏24 KB

Labview FPGA encoder reading

hello,
I an new in LabVIEW FPGA programing so I would appreciate any help. I am using sb-rio 9636 card and optocoupler for speed messaurment of DC motor. I have conected everyting right and the sensor is giving me date. But messauring the speed the oscilations of sensor data are huge. I am not changing the speed and motor continiousliy is rotating in the same speed but data are not the same. For example im 12 V that is the max speed motor schould rotate in 6500 rpm/min but in one second it is showing 6500 and in the other 5500 rpm/min. think that there is not problem in the code but that the messaurment are not reliable. I will put my code. I need to know is there anz other way to do encoder readings.
Thank you

I don't see anything in your loop that guarantees the timing of your sampling of the digital encoder pulses. It appears you expect that loop to run at 1MHz based on the uS unit label on your time of flight indicator.
Because you are using front panel indicators for some of your calculation variables, I can't see all the numbers going into your calculations.
How much variance do you see in the time of flight measurement on your front panel? You must remember that you are making measurements in whole integers of uS. How much change in the RPM calculation do you see if the uS measurement drifts by 1 uS?
If the impact of 1uS change in pulse to pulse measurement has a big impact on your calculation, then you will need to adjust your algorithm to get a more precise measure of the time of flight.
Some ideas:
The faster your sampling loop runs, the more likely you will sample the signal right after the pulse transistion. Consider using a Single-Cycle Timed Loop to sample at speeds in the 40MHz (25ns period) range. This will give you more precision. One risk I can't rule out in your existing code is that you may be sampling slow enough that in some cases you miss a pulse completely. If you want to ensure that you do not miss any pulse edged, then you must ensure that the loop is sampling at least 2x the frequency of your pulse train, assuming the pulses have a clean 50% duty cycle. If that duty cycle is not 50%, then the maximum sampling period must be shorter than the shortest pulse you expect.
Rather than measuring the time difference from pulse to pulse, measure the time of 10 pulses, or 1000 pulses, or some other larger number. This averages a larger number of pulses so that the difference of 1us resolution has less impact on the calculated measurement.

Graphing Encoder Counter Input in LabVIEW Signal Express

In LabVIEW SignalExpress, using a simulated daq system with a counter input, I set up a DAQmx Acquire of an Angular measurement based on a quadrature encoder. Acquiring N samples, I acquired a table of measured values. I would like to plot the results, however, I am not given the option to view the data in any other format. I can plot if I acquire one sample, but that does not allow me to sync the data with the analog input signal I would also like to acquire and view. I had to use an external clock to take the encoder data, so the data is acquired a double datatype. I would like to be able to view in realtime, encoder position with respect to time.

HI,
I want to obtain of this combination of hardware and software a system that allow me acquire a signal of the load cell and the counts of the incremental encoder’s pulses and represent in a graphic the force vs the distance.
The distance is pick up to a incremental encoder in a worm gear that with its movement, move a load cell in a base. the reading of the position is in millimeters.
In this moment, I can only represent the force, the position is only visible in a display, I want to take a samples of the force and the count in millimeters, ten or more times per second and perform a graphic in a real time.
Thank you for your answer
Best regards
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What is the proper way to set up an encoder on an Elvis prototyping board with Labview 2010?

I am using a PCI-6024E with an Elvis I and MCU Project Board. I've tried using the quadratureencoderm-series.vi as well as experimenting with the counter channels in the Measurement and Automation Explorer; however I have been unable to find the proper channels to read the data from this encoder. I'm having trouble configuring the counter to work properly. Can anyone tell me which pins I should be connecting the encoder signals to? I've attached a datasheet for the motor and the encoder. Any help would be appreciated.
Attachments:
MT-003-datasheet.pdf ‏381 KB

Hi jns0086,
I see your problem. I believe that example was written using Traditional DAQ, a set of drivers and functions that have since been replaced by DAQmx. What version of LabVIEW and Windows are you using? There are some compatibility issues depending on your version on LabVIEW and your operating system.
In the meantime, if you have everything connected properly, you should be able to count your edges using one of the built-in LabVIEW examples. Go to Help>Example Finder and then browse for Hardware Input and Output > DAQmx > Counter Measurements > Count Digital Events > Count Digital Events.vi. See if that helps.
Have a great day,
Chris
Applications Engineering
Applications Engineer
National Instruments

How do you convert the encoder counts to RMP of the motor using a myRIO in LabVIEW?

My intent is to gain hardware interfacing and general Labview experience. I am using a myRIO to control a Pittman 8222 34V Brushed DC motor (Motor Specs).
I recently created a code to control the angle of this motor using PID, which was visually implemented using the black disc with a white tick mark on it (see attached picture: "IMG_2523").
I now want to control the speed of this motor againg using PID, but I am not sure how to properly convert the encoder counts to RPM of this motor. I have attached 2 screen shots of my block diagram and my front panel for reference ("Capture" and "Capture2"). In the front panel picture, you can see my "actual" speed of the motor is a very choppy signal when it should theoretically be a flat line. To get the RPM, I currently use a shift register to store the current count value (which I converted to deg, then to radians), and then subtract the previous run's value, then divide by the while loop sampling time (10 ms). This would give me rad/s, which I then wrote a subVI to convert it to rpm.
Any help would be greatly appreciated, thanks.

Hi,
One thing you could try doing is verifying that the conversion from rad/s to rpm is working correctly.
This tutorial might also be helpful. It's not using the same hardware that you are, but goes through the general steps using PID control.
CompactRIO Motor Control Basics Tutorial: http://www.ni.com/pdf/labview/us/compactrio_motor_control_basics.pdf

MP3 Encoder in LabVIEW

Hallo,
Has anyone experience in integrating a MP3 encoder engine into LabVIEW.
I've thought of taking the LAME encoder as dll, but I haven't found any
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Oliver Friedrich

Hi Oliver,
There is an mp3 example program on NI's website that is available for download. It basically uses activex calls to run windows media player. If you want to have a standalone mp3 player, you may be better off searching the mp3 forums for an encoder dll or source code that you can compile into a dll or exe. In any case, here's the link. Enjoy!
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National Instruments
Jeremy L.
National Instruments

Linear encoder (newall SGH) controlled with motion cotnroll UMI7764 and LabView

Hi,
I would like to intsall my linear encoder (SGH PC) onto the motion controll box (UMI7764). After that I have to use LabView to controll the encoder. It should give me the position of a piston and also the limits for this piston. So at first I just want to controll the position of the piston and then give the limits or controll the piston with it.
My problem is I have no idea how? How can I get my signals out of the encoder into my LabView programm? I got the key for the pins but still unclear how to get my signals and what to do with them.
Sorry, I am not used to use LabView.
Thanx

Oh, ist mein Englisch so schlecht
Dann formuliere ich meine Aufgabe einfach noch mal auf Deutsch um Missverstaendnisse auszuloeschen.
Meine Aufgabe ist es einen Linear Encoder (SGH PC) an einen Piston (wie heisst das auf Deustch?) anzubringen und anzusteuern. Zunaechst soll nur die Position des Piston damit bestimmt werden, danach aber auch Vorgaben gesetzt werden. Heisst, ich gebe eine Routine vor und der Piston macht das dann hoffentlich auch.
Um den Encoder ansteuern und auslesen zu koennen stehen mir eine Motion Controll Card (UMI 7764) und eine PCI 7324, sowie LabView 8.6.
Zur Zeit sind wir noch mit der Installation des Encoders beschaeftigt, doch bald werd ich auch programmtechnisch handlegen muessen. Leider hab ich noch nie mit einer PCI oder all dem Anderem gearbeitet und kenne mich daher nicht damit aus.
Fang ich also mit einer Grundlegenden Frage an: Hat LabView ein VI was es mir ermoeglicht die benoetigten Kanaele aus dem PCI auslesen zu lassen und wieder zu schliessen? Dann waere die Positionsbestimmung ja hoffentlich nciht so kompliziert.

Read "Encoder counts per revolution" in Labview

Hello,
I have set up an 'NI Motion Device' in the Measurement & Automation Explorer. I would like to read the value of 'Encoder counts per revolution' in labview.
I do not want to re-enter the value of 'Encoder counts per revolution' in my labview code; I would like to write the value once (in the Measurement and Automation explorer), and then have labview read this value.
How does labview access this value?
Regards,
Myles

After speaking with a few different applications engineers at NI (see ref#2042315), the 'NI Motion' module only supports setting the counts per revolution (not reading them). The 'NI SoftMotion' module allows for the reading of "Encoder Counts per Unit' under the softmotion property node.

Mircosoft Expression Encoder in LabVIEW

I am trying to use the Mircosoft Expression Encoder in LabVIEW, Mircosoft support the SDK, it can be download from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=5c3c5f97-678c-4c99-a7fc-f84f320c626f
I google this topic, it seems some one has done this and put a LabVIEW 2009 VI in LAVA, see my attachment.
The problem is I cannot use the dll in LabVIEW, it give me "The selected file is not a .NET assembly, type library or automation executable." I don't know is the dll's problem or LabVIEW problem.
Attachments:
ExpressionEncoder.vi ‏31 KB
Microsoft.Expression.Encoder.zip ‏433 KB

The problem is that this is a .NET 4.0 assembly. LabVIEW only supports .NET 3.5 assemblies. I am not familiar with this component, but you might check to see if there is some earlier or alternative version built for .NET 3.5.
Jarrod S.
National Instruments

Linear encoder in LABview

I've managed to get three seperate sine waves out of my encoder. At this point i'm wondering what i have to do within labview to translate these three sine waves into some sort of position indication.
Here is some information:
The DAQ card that I have is a PCI-MIO-16e-1 The linear encoder that i'm attempting to use it a RSF Elektronik MS 6x i can't find the data sheet for the exact model but i've attached a pdf which talks about the variouis signals that it outputs. Also the table below is a table that I found in the documentation for the MS 6x that I have which explains the various pin outputs of the encoder. I hope this help please let me know if you need any further information.
Pin                   Signal
1                      +5 V                                                                Supply
2                      V Gnd              Analog ground             Output 2,5 V typical
3                      R1                    Analog voltage signal
4                      A2                   Analog voltage signal                2 Vss typical
5                      A1                   Analog voltage signal                2 Vss typical
6                      0V
Attachments:
44769_5.pdf ‏124 KB

Duplicate post
Regards,
André
Using whatever version of LV the customer requires. (LV5.1-LV2012) (www.carya.nl)

4B6B Encoding Decoding on Labview

Can any body guide me how to implement 4B6B Encoding and Decoding in Labview.
Please share an example of 4B6B Encoding and Decoding.
Thanks
JK.

I don't know how to do this, but the technique was been patented in 1994 so if this is going into something that you will be reselling or is included in a program that you are writing for a client for pay, you might be on really shaky ground...
Mike... (Who isn't a lawyer, and doesn't even play one on TV)
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

LabVIEW USB-6366 sample 2 AI and Encoder Value triggered with X1-Encoder (not with sample clock) - Help needed, please

Hello World,
after 10 years of LabVIEW experience I'm totally lost.
This is my first project with DAQmx and I don't know how to handle it.
My setup: Windows7; LabVIEW 2012 DevSuite; X-Series USB-6366
My goal: Trigger the encoder value and 2 Analog Inputs
I would like to get one result for the encoder value and each of the two analog inputs for each change of the encoder value (not more!!! I don't want to sort a huge amount of data afterwards)
I've been able to configure it with the Measurement and Automation Explorer, but have no clue how to get this in a LabVIEW configuration.
All examples I could find are reading the analog Inputs and the Encoder with SampleClock. That's not what I'm looking for.
I would greatly appreciate if someone could guide me to my solution.
I've attached the exported confiuration of the Measurement and Automation Explorer.
Thanks in advance, best regards,
Balze
P.S.: Sorry I had to ZIP the *.nce file, because NI doesn't allow to attach *.nce files
Solved!
Go to Solution.
Attachments:
configData.zip ‏290 KB

Hi RupiDo, hi Kevin P.
thank you for your effort and your willingness to help me. I aprreciate it!
@ RupiDo:
I'm aware of the DAQmx Timing.vi but where do I find I/O filtering (which context menue?)
DAQmx is a Monster for me. It's for sure felxible and powerfull but how to configure it is not obvious for me. Also the dependencies are unclear to me. I tried things and get an error at run-time that this or that is not supported, reserved, ....
Nyquist Shannon doesn't matter very much for my task. I measure DC voltages with litlle changes. But thank you for pointing this out.
Retriggerable property node?? Where's that? (This maybe not obvious for me, because it's a german LabVIEW I've got to work with)
@ Kevin P.:
Yes, it's a quad-encoder with A,B and Z but Z is still unused (and will be unused for now)
I've got similar problems to setup your solutions.
When I try to configure "Change Detection" I get error messages, that it's not supported. "allow buffer overwrites"??? I seached for it very thoroughly,but without success.
I looked at a lot of examples but always found solutions with buffered aquisition. I'm already willing to use buffered aquisition, but I even can't setup this.
I FEEL SO STUPID Over 10 years LabVIEW experience and the first DAQmx project let's me stumble.
I tried a buffered aquisition based on an NI example. But it only works for one analog input channel. The other brings up en error (-50103). Which one of the two analog channels brings the error is randomly.
Maybe someone could explain me, what leads to this error, that I could start understanding DAQmx.
I've attached the VI (LV2012) and screenshots of the frontpanel and the blockdiagram.
Thanks in advance, best regards
Balze
Attachments:
Meas Angular Position-Buffered-Cont-CtrClk-1.vi ‏72 KB
vi_panel.png ‏95 KB
vi_block.png ‏87 KB

Simulating Optical encoder in LabVIEW

I need to reproduce the behavior of an Optical Encoder. The idea would be able to determine the speed and the direction in which the user is turning a knob or a dial in a graphical interface. It is possible to join the two end of a knob 0 and 10 by selecting the Position/Size/Select tool and moving the value 10 of the indicator toward the 0. I don't know if there is something that already exist.
Best regards,
Nitrof

Nitrof wrote:
> I need to reproduce the behavior of an Optical Encoder. The idea
> would be able to determine the speed and the direction in which the
> user is turning a knob or a dial in a graphical interface. It is
> possible to join the two end of a knob 0 and 10 by selecting the
> Position/Size/Select tool and moving the value 10 of the indicator
> toward the 0. I don't know if there is something that already exist.
>
> Best regards,
>
> Nitrof
I don't think there is a control that does this. To work just like an
optical encoder it would be nice to be able to cast the control to an
enumeration (enumerations wrap around on increment). It would also be
nice to incorporate the counting into the control, like a multiple turn
potentiometer that never
runs out. Next, you could make something using
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that you can import.

BCH Encoder Labview

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