Arbitrary signal conversion

Hi!!!!
I am ABHRO from Banglore,India.I have made an arbitary signal from the data points I am having and now I need to convert that signal to another form of which I know the relation(I mean the equation).
I wanted to know if there is any procedure to convert the input signal to another form and further use it.

Couldn't you just
input array -> equation -> output array?
Kudos and Accepted as Solution are welcome!

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Arbitrary signal generation acquire 5411 5911

An arbitrary signal generated on a PCI-based NIFGEN(5411) is not acquired correctly on a PCI-based NISCOPE (5911). I use RTSI to synchronize the two boards (5911 is the master). When the 5411 board has generated the waveform the 5911 board should start acquiring immediately, but it seems like the board does not receive the correct data the first several times (It jitters around zero). Does anyone know what the problem might be (I have attached my VI)? If not does anyone know how to examine the data actually generated by the 5411 board?
Attachments:
5911-5411_interface.zip ‏144 KB

You may want to post your query under the Measurement Hardware section of the forum for a faster response.
Rgds,
Khalid

CAN Frame Signal Conversion With XNet

When dealing with CAN, most new developer struggle with the Frame and Channel (or Signal) conversion. Developers are trying to get away with using the cheapest CAN hardware, and as a result are opting to not use XNet hardware but instead use things like the USB 8473, or using non-NI hardware like the ValueCAN by Intrepid, or using Vector hardware, or CAN to serial adapaters. The problem with all of these is you generally just read and write frames which is the raw form of CAN. When using these cheap devices you can't ask the CAN bus what the signal Bus_Voltage is, instead you need to perform a frame read, find the frame associated with the signal, then pull out the bits for that signal, then scale the signal based on the signal selected.
All of this is doable but a pain and can be very custom. That's one reason NI came out with the Frame Channel Conversion Library. This library converts from Frames to Channels using an industry standard CAN database file. The problem with this library is it hasn't been updated in 5 years, and has known issues which likely will never be fixed.
NI has since come out with XNet which supports reading and writing signals on XNet hardware. The XNet drivers also support converting Frames to Signals without needing hardware at all. This conversion has several limitations, and really only works for getting the latest value for a signal, not all values. And in addition to that if the signal was never seen, the value will be the defaul value for that signal, not NaN.
So I wrote a wrapper around the XNet conversion library to handle going from signals to frames, or from frames to signals. Anyone looking to use a DBC file, on hardware that only supports frame API should use this conversion library, or at least use the XNet conversion sessions.
CAN Frame Signal Conversion Using XNet
Unofficial Forum Rules and Guidelines - Hooovahh - LabVIEW Overlord
If 10 out of 10 experts in any field say something is bad, you should probably take their opinion seriously.

Hello Hooovahh,
Nice work . It’s very useful.
I’m also converting CAN Raw data to Physical values in my project. Yes, your correct XNET APIs have some limitations. as you mentioned, there is one more limitation I found,
If your Message Data length (Payload) is 4 Bytes (example) and other CAN Frames are having more than 4 Bytes then its throwing Error (Error Code -1074384737).
While converting CAN Frames to signals, we will get different Payloads but, our selected signal message have 4 bytes then XNET will gives an error (at the time of Data Conversion).
As per attached Snap, My Signal is related to IDxBB and I’m sending two different Frames then XNET will not convert.
Hooovahh Wrote:
NI has since come out with XNet which supports reading and writing signals on XNet hardware. The XNet drivers also support converting Frames to Signals without needing hardware at all. This conversion has several limitations, and really only works for getting the latest value for a signal, not all values. And in addition to that if the signal was never seen, the value will be the default value for that signal, not NaN.
When we will send Frame by Frame then we will get all values (not only recent values). XNET will take previous value (if data is not present for Next iteration)
Please check this snippet for all values & NaN Display.
Munna

Synchronous arbitrary signal generator

I have Labview 7.0, PXI-1042, pxi 6070E, scb-68, windows xp.
Is it possible to synchronize an arbitrary signal generator and a simulated signal generator?
So far I have been unsuccessful.

Hi Cool,
The hardware output of the PXI-6070E board is independent of the software running in LabVIEW. Once LabVIEW sends the command to write the output buffer, the hardware will work independently of the software.
There is a certain degree of synchronization that can be accomplished using DAQ Occurrences, which uses an interrupt to indicate when a certain amount of output has been achieved. However, the difference between the DAQ board sending the interrupt and LabVIEW processing that interrupt, amounts to a period of time that doesn't enable you to perform tight synchronization.
If you are looking for output rates in the kHz, this might, however, do the trick. The problem is that there is always going to be a difference since the OS (Windows) control
s the multitasking of applications and LabVIEW. This causes LabVIEW not to run deterministically. The hardware will always output at a specific rate where as the LabVIEW will not be able to simulate completely at a specific rate.
I would take a look at DAQ Occurrences in the LabVIEW Help File. This will give you your tightest synchronization. Hope that helps.
Ron

Simulate arbitrary signal getting rms value

Hello!
I´ve got a .lvm file (attached as testpwm.txt) that generates a preview in Simulate Arbitrary Signal but shows nothing in the waveform graph. I would like to calculate the rms value and the duty cycle of the signal, but it doesn´t work together with the Express VI. I have also tried to build the waveform with Read waveform from file, but it doesn´t work either.
any ideas?
Attachments:
testpwm.txt ‏24 KB

Hi Dongre,
What do you mean by "but value varries from 0 to rms which is not required. "
If you are using EPS 2014, you should first identify the type of data acquisition cards you are using for your cRIO 9076 (SAR of Delta-Sigma), and then choose the examples with the corresponding type in name in the Power Quality folder. These are more ready-to-run than the examples in Basic Power Measurement which are for DAQmx, but which could also give you a straight forward view of how to measure RMS.
You need to check the data acquisition modules on your cRIO for acquisition precision. If they are different from what's used in the examples, you need to manually modify a bit. Refer to the link below for how to adjust precision when you change for another module.
http://forums.ni.com/t5/LabVIEW-Electrical-Power-Suite/Wrong-Voltage-Values-using-NI-9225-and-ELectr...

Simulate arbitrary signal VI

Hi,I want to use simulate arbitrary signal VI to load the data and then output it to control the shaker motion, one problem is that when the VI outputs the data point-by-point, its time interval is not the real time step in the data, so how can I change the time interval, if this can not be achieved with simulate arbitrary signal VI, what VI should I use?
thanks a lot,

Hi all,
I hope you are all fine. I am trying to generate the simulated brain sign. I got all the data set for the time and the value of y-axis but when i used cDAQ NI 9178 to interface my signal and see it on oscillscope, there is error. in the software it works ok but hardware can not .i dont know what is wrong,
kindly can you help me in this issue.
error is
Error -200292 occurred at DAQmx Write (Analog 1D Wfm NChan NSamp).vi:3
Task Name: _unnamedTask<14>
Attachments:
trial1.vi ‏1608 KB

Can we design analog to digital signal conversion block diagram (ADC) in labview

hi every one,i've doubt i.e can we convert function generator output (i.e analog signals) to digital signal in labview......can anyone help me how to create ADC circuit that means ADC Block Diagram in LABVIEW.....please give me solutions for my problem

Hi guru,
from signal generation VIs you get arrays containing float values (aka DBL). Those floats are just digital values made of 0s and 1s…
Any value in your computer is digital!
To provide a solution you need to rephrase your question! What exactly do you expect as result of your operation?
Edit: kkkkkkk ur ckt ???
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

Differential Signal to Single Ended Signal Conversion

Hi,
Im facing a problem here. I need an ADC that reads 0-20mA. The signal comes from a signal conditioner that creates a differential signal. However, a NI device with single ended inputs is much cheaper than differential inputs.
The signal conditioner already exists and I cant change that.
Im looking for something that can convert the differential signal to a single-ended signal.
I tried finding an IC that does that, but couldnt find one. Do they exist?
Maybe its easier for voltage than for current.
How is this usually done?
Best regards,
Arvel

Use a current sensing resistor and then use a current shunt amplifier. The amplifier will amplify the voltage drop across the reistor. From there, you can just read the output voltage with a DAQ. Create a DAQmx scale to do the math to convert that voltage into a current reading.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

XNET Signal Conversion

Hello all,
Please help me on my VI.
I want to read the more data from log file (i.e. >2GB) with read from notepad file( line by line) or spread sheet. This output I’m giving to CAN frame (with NI XNET).
In NI XNET Convert.VI I’m getting last frame values (Signal data), so how can we get the all frame values with time interval( for selected signals).
My log file contains two types CAN networks, I want to read both .DBC files with NI XNET convert.VI and I need extract the data for selected signals .
Please check my VI and give me your valuable suggestions.
Thanks & Regards,
Guru
Munna
Attachments:
sample for CAN signal.zip ‏28 KB

Hello all,
Please help me on my VI.
I want to read the more data from log file (i.e. >2GB) with read from notepad file( line by line) or spread sheet. This output I’m giving to CAN frame (with NI XNET).
In NI XNET Convert.VI I’m getting last frame values (Signal data), so how can we get the all frame values with time interval( for selected signals).
My log file contains two types CAN networks, I want to read both .DBC files with NI XNET convert.VI and I need extract the data for selected signals .
Please check my VI and give me your valuable suggestions.
Thanks & Regards,
Guru
Munna
Attachments:
sample for CAN signal.zip ‏28 KB

Generate single ramp signal

I cannot seem to figure out the time parameters of the Simulate Arbitrary Signal.
I want to make a single ramp from -1 to 1 over .990ms then back to -1 in under 10us. So when I put it in a for loop I can get N sawtooth cycles.
I've been pulling my hair out trying different options of the define signal dialog and can't make it happen.
Can someone help me understand the dx relation to the datapoints and how they are affected by the write/sample numbers in the DAQ part? Please.
Christopher
Solved!
Go to Solution.
Attachments:
one_sawtooth.vi ‏2362 KB

This should get you started. You will need to set up the analog output in the software to match your system. If you change the frequency and sample numbers and the loop delay then you can make it go faster and slower much easier.
Tim
Johnson Controls
Holland Michigan
Attachments:
one_sawtooth[1].vi ‏24 KB

Generador Onda Arbitraria

Buenos días!
Me pongo n contacto con ustedes porque estoy realizando un generador de ondas para Labview y ahora mismo estoy atascado. He realizado la parte de generación de ondas predefinidas, pero ahora me gustaría hacer un módulo de onda arbitraria, es decir, que nosotros le demos los valores y muestre por pantalla la onda que nosotros hemos definido.
La idea es que esta señal se repita y se pueda ver en un osciloscopio físico.
Y más o menos tengo el concepto, pero no se como implementarlo en Labview
Si me pudierais echar una mano. Muchas gracias

Se que existe un bloque que se llama "Simulate arbitrary signal" pero para introducir los datos de la señal arbitraria hay que meterse en el diagrama de bloques e iniviar este VI desde allí.
¿Habría alguna forma de que se pudieran introducir los datos de la señal desde el panel frontal?
Muchas gracias

An arbitrary waveform generator using the DSP Module

Hi Guys,
Just got my hands on LabView and the DSP Module, and having a bit of fun atm. Great products. I'm currently using the TI DSK6416, and was wondering if there was a labview model/example of arbitrary waveform generation using this...? Perhaps using a DDS method or something similar?
Thanks in advance...
GibbGodD

GibbGodD,
Hello!
There are quite a few Waveform Generation VIs within Labview, including the Simulate Arbitrary Signal Express VI and the Arbitrary Wave VI. Unfourtuantly, these are not available within the DSP Module. There is a special group of Embedded Signal Generation VIs for the DSP Module, of which one is the Simulate Signal. Take a look at these VIs as perhaps you could use them to build the waveform you are looking for.
To answer your question, I wasn't able to locate a specific example that matched what you were looking for, but if you to Help >> Find Examples >> Toolkits and Modules >> DSP from within LabVIEW you should be able to find some great DSP examples. Particular, the example project "Variety of Signal Types.lvproj" shows the different types of signals the DSP target can generate.
The majority of Arbitrary Waveform Generation information that I was able to find is all related to our Function Generators but not for the devices supported for the DSP Module.
Best of Luck!
Ben Sisney
FlexRIO V&V Engineer
National Instruments

Sim. arb. signal within Timed Loop?

Hi there,
Is there any inherent reason I couldn't/shouldn't put a Sim Arb Signal VI within a timed loop? I have a scenario in which i need to modulate an arbitrary signal as the experiment is being run. I've placed the express vi inside a timed loop set to execute every millisecond. The express VI is setup to generate a single point of a arb signal with a dt=1. It seems however that it generates the whole signal each time the loop is called. Is there an appropriate example or tutorial somewhere out there in cyberspace?
Apologize for not posting an example, but I am working from home tonight.
Regards,
Matthew Pausley
NC State University
Raleigh,NC

Matthew,
I have tried making the simulate arbitrary signal vi output a singal point using your suggestions and it worked. Perhaps you need to compare the VI you are using with this one.
I hope this helps.
Steven T.
Message Edited by Steven T on 10-16-2006 11:46 AM
Attachments:
example2.vi ‏110 KB

Poor colour depth/banding with Apple Mini-DisplayPort-to-VGA adaptor?

I'm using the Apple Mini Display Port to VGA adaptor to hook my MBP up to a projector in the theatre where I give lectures.
I am getting colour depth/ banding issues - images seem to be displayed in thousands of colours, rather than millions, creating really bad banding problems.
I know it isn't an issue with the projector - for comparison purposes I tried playing a DVD through a DVD player connected to the projector, and then through the MBP connected to the projector, and the diference in colour depth was really noticeable. In fact it was virtually unwatchable through the MBP.
Is there a preference pane I'm missing somewhere which will increase the colour depth?
Is there a better adaptor than the Apple one that I need to buy?
Or is this a problem inherent in the minidisplay port to VGA conversion process?
Any tips or pointers would be greatly appreciated.

If your monitor has DVI input, get the DVI adapter. DisplayPort is digital, DVI is digital, but VGA is analog - the signal conversion will result in a (slight) drop in quality.

Mini DisplayPort to VGA Adaptor : Gateway Monitor FPD1760 - Compatible ?

Hi. Is the Apple, Mini DisplayPort to VGA Adaptor compatible with Gateway Monitors?, I own a Gateway FPD1760 (Specs : http://www.dealtime.com/xPF-Gateway-Gateway-Monitor-FPD1760).
Just wanted to know if I should be going with Mini DisplayPort to VGA Adaptor or) Mini DisplayPort to DVI adapter, as I have heard too many complaints about the former.
Thanks in advance

If your monitor has DVI input, get the DVI adapter. DisplayPort is digital, DVI is digital, but VGA is analog - the signal conversion will result in a (slight) drop in quality.

Arbitrary signal conversion

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