How to generate two different analog signal in two different VIs

I'm using a PCIe-6321 board and a SCB-68 connector block. As it has two analog output I would like to use one of these output in one Vi to generate a square waveform and the other output in another VI to generate a sine waveform. Each VI work perfectly separatly but if I run one then the other, the second one doesn't send any signal. Since I don't want to merge the two VIs (It's more convenient to operate them separatly), how can I figure out to make them work together (sometimes).
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I assume you get error -50103 (resource is reserved) at either on vi.
It's not possible to run two AO channels independetly from each other with different VIs since both Tasks are trying to request the same timing engine at the DAQ device.
Christian

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Outputting different analog signals across 4 outputs

Hello All,
I need some help outputting 4 different analog signals from the PCI 6711 board. I plan to use the function waveform vi from the analog generation pallette. My goal is to be able to enter in the 4 necessary functions, there sampling information, and then output them from the four available analog outputs available on the board. I've seen the example code for outputting across multiple lines, but it doesn't seem like it is able to create unique waveforms across the outputs, they are all the same waveform. I've attached what i thought would work, but i can't get my number of lines in data to match my number of lines in task.
Solved!
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Attachments:
Analog program.vi ‏34 KB

More specifically, choose the polymorphic instance of Analog->Multiple Channels->Multiple Samples->1D Waveform.
Your current instance that you chose is for just a single line.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
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How do i send an analog signal to trigger another program

I am trying to send out an analog signal from labView that will start Bioware. How can I do this?

Hi Orbz,
There are 3 Send modes in Logic:
• Pre Fader (original signal is sent before it reaches the channel strip's fader etc.
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• Post Pan (send before volume fader and Pan/Balance adjustments).
Click and hold on the Send slot in your synth channel strip and select Post Pan fro the drop-down menu.
Funnily enough I've just finished writing a tutorial about this very topic!! It's not published yet, but will appear on the macProVideo.com blog in the coming days...
http://www.macprovideo.com/blog/

Need Help on How to Generate Pulse Width Modulation signals

Hi,
I am New in using NI board and programming using LabView. I have no idea on how to start to generate, use what function in order to create a PWM signals.
My project needs:
-PWM signals with 15kHz frequency.
-Duty cycle varrying from 0%, 25%, 50%, 75%, 100%.
-By using the generated PWM signals to control the half-bridge (MOSFETs) of boost converter and buck converter to varying the voltage of 24V battery to feed in my DC motor.
The NI board that I use is (NI - sbRIO-9642).
Can I have a clear view on what to use, how to generate, and by using what functions to generate the PWM signals.
Sorry for the inconvienient, but I really desperate for help in this. Thanks a lot. I am appreaciate it.
The attached is the circuit the half-bridge motor controller that I will used.
Attachments:
half bridge.jpg ‏13 KB

Hi Ronald,
in this thread a very similar question came up. You can use the same approach on your sbRIO.
For the frequency you gave you should use the FPGA present on the sbRIO - as is shown/discussed in that other thread! I also suggest that other thread because of the "deadtime" feature used to prevent shortcut problems when switching your MOSFETS simultanuously...
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

How to generate this type of signal?

While I am connected to the sensor, the analog signal looks like this:
http://warsztaty.samochodowka.internetdsl.pl/serwishdd/poradnik/elek_autom/czujniki/cz_pol14.jpg
The sensor is in the workshop and I need to work with this signal at home...
It's a signal from inductive sensor which measures RPM of motor shaft. Each peak is synchronized with TDC of piston. I also need to control the frequence of emulated signal to simulate the speed changes.
Any ideas?

I would record the signal to file after acquiring with a DAQ card.
Then you could read this signal from the file and build it into a waveform. To change the frequency, just modify the value for dT that you bundle into the waveform.

Determining Analog Signal Frequency with Prebuilt VIs

Don't know what is wrong with this code. Am trying to determine the frequency of a signal from an analog signal (paddlewheel flowmeter). As a starting point, I'm using a simulated square wave with the "Timing and Transition Measurements" VI and am getting following error:
~~~~~~~~
Error -20308 occurred at Timing and Transition Measurements -> frequency_determination_example.vi
:3" (waveform index 0 of 1)
Possible reason(s):
Analysis: The waveform did not cross the mid reference level enough times to perform this measurement. Check the signal length, reference levels, and ref level units.
~~~~~~~~~
However, there seems to not be any options in the "Timing and Transition Measurements" VI to set mid reference levels.
Any insight into why this simple problem is occuring would be appreciated. Attached is my program's simple code.
-tsippel
Attachments:
frequency_determination_example.vi ‏101 KB

Hi,
Dennis was right (without looking at the code). You generate one (1) square wave, if you had generated 1000 sampled you'd get the correct answer.
Ton
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My LabVIEW Ideas
LabVIEW, programming like it should be!

How to generate BPSK and QPSK signals with Labview and ARBS?

Has anyone used Labview to program a Wavetek 75 or equiv Arbitrary Waveform Generator to produce BPSK and/or QPSK signals.

You can use Modulation Toolkit 2.0 for LabVIEW to generate PSK signals (including BPSK and QPSK) using common PSK configuration parameters.
http://sine.ni.com/apps/we/nioc.vp?lang=US&cid=12855
You can use resampling tools present in Modulation Toolkit if you need to resample the generated data to a different sample rate for your third party AWG.
In addition, Modulation Toolkit integrates seamlessly with NI's high-speed signal sources, including the NI 5421 for PXI:
http://sine.ni.com/apps/we/nioc.vp?cid=12472〈=US

How to generate a single output pulse on 64 different digital out lines (PCI-6513) each with a different start time relative to an event in a main program loop.

Long question.
I am running a main program loop of 60 msec. At one point in the loop I create a 64 element array of delay times. At that point I need to begin outputting a predefined single pulse to each of the 64 lines on my PCI-6513. Each line outputs the pulse with a starting delay set by the "delay time" in the array.
Each delay time is such that the pulses will be done before the next loop commands another one.
Thank You
Roger

Hi,
You have multiple ways of doing this, since there is no timing engine on the 6513 your code is going to control the output of the card, which is what we called “software timed”. If you take a look at the example called: “Write Dig Chan.vi”, you can individually control each line.
So to change the state of the line; since you have an array of delays time you can aid yourself with “stacked sequence structure” where in each frame you control the time it takes to go to the next frame and the data been written to the card.
Another option is using a state machine where each state write the data you want and you can also control the time between states. For further references take a look at this article Application Design Patterns: State Machines.
I hope it helps
Jaime Hoffiz
National Instruments
Product Expert
Digital Multimeters and LCR Meters

Compare two analog signals.

How do I compare an analog signal to another analog signal to see which signal has a higher value? I want to display the result on the front panel using an LED indicator.
Solved!
Go to Solution.

Sorry about the lack of inforomation.
I have photodiode voltage four output signals go into the SCC-68 module. The SCC-68 module is hooked up to the PCI 6224 M DAQ Card.
The signals have almost no noise to them, and I am trying to compare the value (voltage) of two analog inputs to see which value is higher. I want to compare the analog inputs of QPD 1.1 & QPD 1.2 from the VI below.
Attachments:
QPD.vi ‏158 KB

MyRIO input analog signal measurement

Hi everyone,
I want to know that how to measurement the input analog signal from a signal generator to the input pin of myRIO. Is it like using myDAQ to measurement? or need to use other Labview function panel? For example, how to trigger the input signal on Labview?
If someone know this, please give me an answer.
Cheers,
Johnson

Hi Johnson,
The minimum software required to program the NI myRIO processor with LabVIEW is the following:
LabVIEW
LabVIEW Real-Time Module
LabVIEW myRIO Toolkit
All of this software is included in an Academic Site License. Additionally, the full myRIO Software Bundle can be downloaded from ni.com and activated with a valid serial number.
You can write programs quickly using I/O-specific Express VIs directly from the LabVIEW palette, which includes an "Analog In" function which you can use for your signal generator input:

Generating sync and PCLK signals for a sony XC-55 camera?

Hello, we have a Sony XC-55 camera connected to a PCI-1408 board that we would like to use in asynchronous mode to capture images. I know that it is possible to use the camera for this purpose because there is a document on how to do this with a 1409 card.
We also have a PCI-MIO-16E-4 board that we have connected to a shaft encoder. We want to trigger the camera when the shaft encoder is at certain positions. This shaft encoder will be connected to the 8 digital lines on the MIO board.
Is there any way I could use the MIO board to generate the required HSYNC, VSYNC, and PCLK signals? I'm thinking about using the PFI signals, but I don't know how to generate the required PCLK signal.

As you may have noticed, the 1408 does not have the same pulse generation capabilities as the 1409. You cannot use IMAQ Generate Pulse with the 1408 to get the required HSync, VSync, and shutter signals. You could use the counters on the MIO board to generate two of the signals, but not all three. It might be possible to operate the camera in internal HD mode and just provide the VSync and shutter. One of the 660x counter boards could generate all of the signals, however you would probably be better off just using a 1409. PCLK is generated internally by the camera and does not need to be provided by the board.
Are you using an absolute encoder in your system? You can read an absolute encoder with the DIO lines on the MIO board, however you will have to conti
nuously poll the lines to find out when you have reached the desired positions and then output a pulse. This operation will be software timed, so there will be some latency. If you have an incremental encoder, you could connect it as the source to one of the counters and output trigger pulses at precicely defined intervals.
Regards,
Brent R.
Applications Engineer
National Instruments

How to generate random numbers in a range?

Hello. i am having trouble finding out how to generate a random number in a certain range. For example i have an array of 100 elements and i want to access one of the elements between 50 and 60, however i cannot find how to generate a random number between these two values.
Thanks in advance

java.util.Random.nextInt(int)
Note that you can get a number between 0 and (max -
min), exclusive. Then add min, and you've got your
number.Obviously you didn't read this. It says to get a number between 0 and (max - min) which is actually what you did. But after that you need to add min. The first step would get a number in between 0 and 5. When you add 20 you'd get a number between 0+20=20 and 5+20=25.

How to make a synchronous acquisition of two analog signals with a one channel DAQ ?

Hi !
It is the first time I use Labview. I have just made some easy VIs, and now, I do not know how to deal with my problem...
My problem : I have only one acquisition card (DAQ Ni 6034E) and I would like
to acquire simultaneously two analog signals. It seems to be possible, in a quasi-synchronous acquisition if the card acquires one point of the first signal, then the first point of the second signal, then the second of the first signal, and so on ... I thougth that I could made two sequencies with a VI of data acquisition in each sequency, with the AI MULT PT. But with this, I think that I will lose the precision of the sampling frequency. And I have to know the sampling fre
quency ...
Thanks for your help !
Carline

Hi Carline,
A PCI-6034E is a low-cost board, which only has one Analog to Digital Converter (ADC).
With only one ADC you can't acquire different channels at the same time. That's why you find a multiplexer before the ADC in this type of board. This enables you to acquire multi-channels at the same rate quasi simultaneously. The samples of the different channels will be interleaved as it is explained in the following knowledge base :
- http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/9379ea091c264b7c86256bc90082ca5d?OpenDocument.
With this method, the sampling frequency is the same for all channels. The sampling frequency of one channel is determined with the "scan rate" parameter. There is only a small delay between the samples
of each channels. When you perform an interval scanning acquisition, this delay depends on the "sample rate" that you specify. To have more informations about this terminology, please refer to the following KBs :
- http://digital.ni.com/public.nsf/websearch/4D1435DF82EF494186256D8A006DD6D4?OpenDocument.
- http://digital.ni.com/public.nsf/websearch/4D1435DF82EF494186256D8A006DD6D4?OpenDocument.
To easily perform such a multi-channels analog acquisition, you can use the VI named "AI Acquire Waveforms.vi". You also can use an example provided with LabVIEW. You just have to browse the NI Example Finder in "Harware Input & output >> Traditional NI-DAQ >> General".
Best regards,
Benjamin
National Instruments France

How to generate two signals using NI myDAQ

Dear Sir:
I designed a circuit to generate a sine wave successfully using Labview. What I want is using NI myDAQ to generate another 3V DC signal as a power supply. I can do this seperately but when I add them together there is an error: NI Platform Services: The specified resource is reserved. The operation could not be completed as specified.
I would like to use A01 to generate a sine wave and A02 to generate a DC wave, could you please check my file and tell me how to solve this problem. I found a solution which generates two signals together but what I need is to control these two signals seperately and using two channels.
Kind Regards
Jeff
Attachments:
signal gen and acquire.vi ‏126 KB

Thanks very much for your kind reply.
No. I tried for a long time, change the samples of each simulate signal to the same but the warning also came out. Could you please check my file and tell me how to solve this kind of problem?
Kind Regards
Jeff

How to generate a pulse train with different pulse width and delay?

How to generate a triggered pulse train with different pulse width. for example, after each trigger signal, let's say 2 ms, then the counter output a pulse with pulsewidth of 1 ms, and then after 3 ms delay after the first pulse, the second pulse was generated with a pulse width of 4 ms. Next cycle when the trigger signal comes, the same two pulses will be generated and so on. Is it possible to achieve this by using 6601 counter card? and if yes, how to achieve this? Thanks!

Unfortunately you can not create a hardware timed pulse train with different widths on each pulse from a counter. Whilst it can be changed on the fly using software, since you require a hardware triggered signal getting the software involved will not give a huge amount of accuracy when the pulse will actually change.
So in short you can't use your 6601 card (or a counter timer) to achieve this
There are three possible Alternative solutions
1 You could use a high speed digital IO device such as the (6533/34) to generate your variable signal which would require setting up the pulse train as a series of states based around the burst transmission mode where the clock would give you your specific timing.
2 A timed analogy output (for example on a MIO card with a clock (PCI-6220 / 62xx), i.e. Not the 6704 style static analogy output cards)
3 A high speed digital waveform card such as the (, 656x , 655x, 654x, 6534, 6533 (http://www.ni.com/modularinstruments/find_right.htm) ) this could then be scripted to work with your triggering and also there is a digital waveform editor which will enable you to set up the pattern you wish to generate (http://sine.ni.com/nips/cds/view/p/lang/en/nid/13555)
Hope that helps
Tim Matthews
NI (UK)

How to generate two different analog signal in two different VIs

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