DIGITAL SIGNAL GENERATION

Hi!
I want to generate a digital signal (0-5V) in order to turn on and off an hydraulic pump. The time on (high) and time off (low) are specified by a MatLab code, so that once the pulse has finished one cycle, the program should be go again to MatLab code and take two times again. Then it should generate the signal again.
Thank you for the help.
Miguel

Thanks for the reply.
I have a system with an hydraulic pump, power supply, transistor and computer. I would like to send a digital pulse from my computer (0-5V) to the transistor. The transistor then closes a circuit (power supply and pump), and the pump starts running.
Then, I would like that each sample (each pulse) has specific width (time on), and also specific time off before it starts with other sample. These times (time on and time off) are computed by a MatLab code.
I'm working with DAQmx drivers and I also have a BNC 2110.
I also attach my code in Labview that I am trying to modify.
Thanks a lot.
Regards,
Miguel
Attachments:
Gen Dig Pulse Train-Finite_original.vi ‏22 KB

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Digital signal generation in cDAQ- 9477 with 1ms resolution.

I am using cDAQ -9477 Digital card with 9178 chassis (USB) .I have to generate some digital signals for 2 seconds. The signal should be
0 (3ms) - 1(1ms) - 1 (2ms) & repeat the sample 0 (3ms) - 1(1ms) ……. upto 2 seconds.
I had generated samples for 2seconds with 1ms duration of each sample.
I am unable to do that with 1ms resolution in cDAQ -9477 Digital card.
Is the above signal generation is possible (each sample -1ms) ?
I am using LabVIEW2009 .I attached the code.
Kindly let me know the suggestions .
Attachments:
Digital Signal.JPG ‏7 KB
Digital.vi ‏40 KB

cDAQ chassis do not currently support hardware timed tasks for digital modules with >8 lines. The DAQmx help defines these devices as "static digital I/O modules". The "Digital I/O Consideration for C Series Devices" section in the DAQmx help describes the capabilities of digital modules on different chassis.
Unfortunately this means you are stuck with static (software timed) generation. Over USB this will affect the accuracy of your signal. You won't be able to achieve the signal you are trying to generate with the current support. Static generation will max out at roughly 1kHz, but Windows can introduce a large amount of jitter. What you really need is a hardware timed task.
This is a feature that could be added in the future. I recommend submitting a feature request, though I know that doesn't solve your problem now.

Generating a digital signal

Hello,
I am trying to generate a digital signal which can be controlled in terms time i.e. Switching ON for 10 minis off for 5 minutes. I tried to generate a digital signal which is going high but unable to control it. As I am the beginner in labview any kind of help is appreciated.
Please see the attachment for the developed block diagram
Attachments:
digital signal generation.vi ‏17 KB

It appears that all you posted is one of the shipping examples. Is that all you've tried? You can't control it because you're not actually doing anything inside the loop. You're simply setting the value high before the loop starts, and not changing it in the loop. What kind of device do you have? Is it software controlled? If so, you will need to keep track of the time inside the loop. You can use the Elapsed Time VI to do this. Attached is a simple example to get you started to see how this can be done. I'm sure you can figure out how to integrate what you did and what I've shown you.
To learn more about LabVIEW it is recommended that you go through the introduction material, tutorial(s), and other material in the NI Developer Zone's Learning Center which provides links to other materials and other tutorials. You can also take the online courses for free.
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Switching signal.vi ‏29 KB

Como puedo instalar ISDB-T/Tb Digital Video Signal Generation Toolkit - MaxEye Technologies en labview 2014

Hola me gustaria que me ayuden con un problema que tengo, descargue ISDB-T/Tb Digital Video Signal Generation Toolkit - MaxEye Technologies evaluation pero cuando lo quiero instalar me aparece un mensaje diciendo que primero debo instalar labview 2012 pero yo tengo labview 2014, como puedo instalar esta herramienta sin tener que cambiar la version de mi labview?

Saludos Mafilu,
Gracias por utilizar los Foros de Discusión de National Instruments, con respecto a tu consulta creo que lo mejor será que contactes directamente al equipo de soporte de MaxEye Technologies para corroborar si existe alguna necesidad especial, o bien, si tienen alguna alternativa.
Support Information
For technical support, contact MaxEye Technologies at:
Phone: +91-80-2527-0024, +91-94-4806-7717
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Can we design analog to digital signal conversion block diagram (ADC) in labview

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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,
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Generate complementary digital signals with dead time between each pulse and controlled by duty ratio

I am to generate two complementary digital signals using NI 9606 conected by RIO Mezannine Card to NI 9683 (Half Bridge DO).
I am able to generate the signals but I am not able to put dead time between high and low signal and also, low and high signal.
Requirement:
(1) When the first signal goes high and the second signal goes low, there should be a controllable dead time.
(2) Also when the second signal goes high and the first signal goes low, there should be a controllable dead time.
I am able to do requirement 1, but I am unable to fulfill requirement 2.
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Attachments:
complementary test 2.vi ‏69 KB

Hi Frank ,
I have already taken note of the example Tannerite has provided and have built my vi ( attached in previous post) surrounding that example.
Now I require to control the PWM duty cycle as you can see from the vi using a knob and that control refers to both the signal 1 and 2.
Now the signal 1 end and signal 2 generation requires a controllable dead time. Similarly, signal 2 end and signal 1 geneeration also requires another controllable dead time.
I am able to do either one dead time at a time using delay but not two dead time simultaneously.
I feel that I have two put the delays at the appropriate data flow point. I am working on that.
I would really appreciate if you could give some insight on how to solve this dead time issue and generate two complementary waveform with dead times whose duty cycle can be controlled by a knob controller in fronty panel .
I have also posted the required timing diagram for reference as suggested by Tannerite.
Best regards.

Measuring digital signals coming from the HSDIO (PXI-6542) with the DMM (PXI-4070)

Hello,
in attachment you can find the program I'm using for my measurement: I'm generating and acquiring digital signals with the PXI-6542 and at some trigger point of one of those digital signals I'd like to capture the measured values on a plot with the Digital MultiMeter (PXI-4070).
It does work if you configure the generation repeat mode as continuous, but if you do have a finite repetition (repeat count is 1) it doesn't react on the trigger, as if it can't find a trigger. On the other hand, if you have a finite repeat count of 30 or more it does react and triggers correctly again.
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Thanks in advance,
Jürgen

Hey Jürgen. I apologize that you haven't gotten an answer yet to your post. I looked at your code and had some questions. What is the source of your trigger to your DMM? I see that you're exporting the data active event to PFI1, and your comments indicate that PFI1 and PFI2 are connected to give you a start trigger for your digital acquisition. Exporting the data active event with a finite or continuous pulse should only give you a single edge per run, though - you wouldn't get a pulse each time. Is your trigger coming from a data line? I didn't see any line in your included data that would indicate a single pulse.
The other thing that I noticed is that you've got no timing dependency between your HSDIO code and your DMM code - they're in parallel with each other. Thus you could get different results run-to-run, since it's not deterministic as to which parallel "thread" that LV will start on first. LV may switch back and forth several times, but let's say that LV reaches the HSDIO Start command before reaching the DMM Start command - in that case, the HSDIO device may finish it's entire operation before the DMM ever starts looking for a trigger, and thus never get the trigger at all. I'm not sure why this would explain why you're seeing the finite case work and the continuous case not, but I wanted to point it out because it could bite you down the road.
I hope some of this this helps get you going in the right direction. I'd also suggest posting HW-centric questions in the appropriate form. There are Digital forums and DMM forums that might help you reach people that will be more familiar with your particular hardware.
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MyDAQ - Generating a digital signal and displaying it on an analog waveform graph

Hi,
I am using the NI MyDAQ to generate a digital waveform with an adjustable frequnecy. This is being implemented into a program I have already written which generates a TTL "like" pulse out of the sound card. I am displaying the output on an analog waveform graph, and I'd like to be able to display the digital waveform generated by the myDAQ on the same graph. (Not at the same time, either one or the other, toggled by a button). I've been messing with arrays and conversions but I cant seem to really get anywhere with it all.
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Solved!
Go to Solution.

Hi Jonny,
The general logic you are using to create a digital pulse train is fine. This VI you've written should work and will create the pulse train based on software timing (which is fine because you don't have hardware-timed DIO on the myDAQ anyway). However, it is usually good practice to start the DAQmx task just before your while loop and then clear the task after the while loop when you press stop.
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If you're not familiar, you can find the examples by going to Help >> Find Examples... in LV. Then, navigate to Hardware Input and Output >> DAQmx >> Generating Digital Pulses or Digital Generation.
Also, here is some additional information about the myDAQ and its counters:
myDAQ Counters
myDAQ Manual
Hopefully this helps.
Chris G
Applications Engineer
National Instruments

Is there a better way to generate custom timed digital Signals

I am trying to generate digital output of high and lows with particular delays on different lines. Each daq assistant is activating single line on a port on USB 6501. There more complex high and lows that I need to generate with variable time difference between high and low. There is codebelow which accomplishes what I am trying to achieve but for executing a long pattern of high and low signal is very time consuming to do this way. I am sure there is a better way to do this, I not a expert on labview so I haven't uncovered its full potential. Can anybody suggest a more effective and a quick way to do this. I would hgihly appreciate. Thanks!
I have not shown in the code below but through DAQ assistant I have initialized lines to low level logic.
Solved!
Go to Solution.

See the attached file
Attachments:
Digital Signal.vi ‏335 KB

How to input/output a digital signal and acquire an analog signal at the same time?

Dasylab, version: 8.0.04
Acquirement Card: PCI1002L
When I use DasyLab to acquire the analog signals is no problem without digital inputs and outputs,
and when I use DasyLab to input or output a digital signal is no problem also, but when I do that at the
same time, DasyLab tell me the rate is too high and stop.
so, I searched the manual book1 (user guide) for that, it showed me :
To internally equalize measurement time and system time in the analog input, digital input and counter
hardware modules, use the following settings:
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the problem is, if I set the Sampling rate to 5Hz, the speed of the acquirement datas is not enough for my
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so, how to improve it? who can give me a example programm for me. thanks!
by the way, I come from China, my English isn't good, I'm sorry.
Allen, China.

Hi,
Have things changed over the years?
I need to syncronise a digital output (Modul NI9474) and an analoge input (AI-Modul NI9203) module. I need to measure time intervals from a flank in signal A to a flank in signal B. I would like accuracies of the order of 1 ms. Currently, the signals are not synchronised, with errors of the order of 2 times the block length (block size x sample rate), sometimes much higher. The best I got so far was a block size of around 20 with a sample rate of 1 kHz.
If I use the master and slave settings on the RTSL settings, my program doesn't run properly.
If I use digital signals for input and output, I can syncronise them with RTSL settings and everything is good, but I can't always do that.
Also, if I do anything in the GUI (such as scrollowing something or going to another window), my output gets screwed up properly.
1. What can be done to synchronise AI with DO?
2. Is there something that can be done to avoid messing up the output when something happens in the user interface? (I know that I am messing up the outputs as they make some valves switch and that is loud).
Thanks in advance!

How do I convert analogue 5.1 surround sound into a digital signal? (Pioneer SE-DIR800C headphon

I understand that my SB Audigy 2 card will only output 5. sound from games through its 3 analogue connectors. How do I convert this analogue signal into a digital one? What hardware do I need to purchase?
I have read the thread on "Digital Connections, SPDIF and Dolby Digital Info", and also I've thoroughly read the "Creative Speaker Connectivity Guide".
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What hardware do I need to buy to convert an analogue 5. signal (via 6 x RCA or 3 x 3.5mm stereo ) into a true digital signal (via optical or co-axial SP/DIF)? Is it some type of headphone amplifier I need? If possible, please recommend makes & models of equipment.

Thanks stefan
OK, basically I have found 3 options for getting digital 5. out of a PC:
a) Creative DTS-60 (approx $90). This converts the SB's analogue into digital, but it's not available in the UK and it also introduces a noticeable 50ms sound delay. Also, who wants an extra box hanging out of their PC?
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c) Buy a new motherboard that has built-in Dolby Digital Li've output, for example the ABIT Fatalty AA8XE. Unfortunately my PC is only just over year old and I'm not quite ready to replace it.
I hope this info is useful for people. Maybe Creative will start making a card with DDL output too.Message Edited by NinjaHeretic on 2-22-2005 08:46 AM

How to check 6 digital signals change value at the same time with PCI-6229??

I am using DAQ card PCI-6229.
Channel 1 generate a digital signal.
Channel 2,3,4,5,6,7 acquire digital signals.
I want to check:
1. Whether the rising edge of Channel 2,3,4,5,6,7 occures at the same time;
2. The time delay from the rising edge of Channel 1 to the rising edge of Channel 2,3,4,5,6,7 is within a certain range.
I know I can use counter to get the two edge seperation time delay. But I only have two counter, it is two time-consuming if I check one by one.
I don't know how to check the rising edge of 6 different channels occure at the same time.
Does anyone has any suggestions?
Thanks

Hello,
You can use the DAQ card's digital input change detection circuitry to detect changes in the input, you can then use a counter to measure the relative time between samples. Please read Page 6-9 DI Change Detection Applications for more information. Let me know if this helps
Christian A
National Instruments
Applications Engineer

When using the LabVIEW Simulation Module, how can I start a frequency sweep with the Simulation Chirp signal generation VI at an arbitrary time after the simulation initial time?

I'm using the Simulation Loop on LV RT when interacting with some hardware (i.e. all I/O is happening in the Sim loop). I'm going to conduct a frequency sweep test on the hardware and want to use the Simulation Chirp function. However, there is no way (that I can see) to trigger the Chirp to start at some event (i.e. I click a boolean on the front panel and enter a case statement). The Chirp is tied to the global time of the Simulation loop and so are it's input parameters. Is there a way to make it relative to some time at which an event happens?

Craig,
Your solution will 'cut' the beginning of the signal and only show the signal afterwards.
To control when the chirp should start, the best option is to use the Chirp Pattern.vi ( in the Signal Generation palette) and use a Lookup table to control when to feed the time. The shipping example (in LabVIEW 2013) shows how to code using a lookup table.
C:\Program Files (x86)\National Instruments\LabVIEW 2013\examples\Control and Simulation\Simulation\Signal Generation\SimEx Chirp.vi
Then, to start from a toggled boolean, look at the example:
C:\Program Files (x86)\National Instruments\LabVIEW 2013\examples\Control and Simulation\Simulation\Signal Generation\SimEx Step.vi
and Here is the example in 2013 (in attachment):
Barp - Control and Simulation Group - LabVIEW R&D - National Instruments
Attachments:
SimEx Chirp with Delay.vi ‏241 KB

Signal Generation through pt by pt Signal

Hello,
I am acquiring signal through serial port, to analyze the signal, i am using pt bt pt signal analysis.
In order to work on it, i used sine wave pt pt signal generation. But remained un successful in generating sine wave through it.
Kindly guide me how could i generate sine wave using pt by pt.
Thanks

Hi Intelligent,
it's not a good idea to start asking by using PNs, I will ignore them in the future!
You wrote:
I already read the help and tried to solve the issue but after not receiving the satisfied results, i posted on the group. As its written in the help that the frequency is in Hz, but the value you have selected for the frequency is 0.01. So its un understandable, also the dependentence of time factor.
- What are "unsatisfying results"?
- Yes, the frequency is given in Hz and I chose 0.01Hz for sake of showing an example...
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Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

My daq 6008 wil not drop the 5V after the VI is stopped, i have a digital signal going from the error out on the daq in the while loop to the error in on the daq outside the while loop and a boolean going to the data of the daq outside

my daq 6008 wil not drop the 5V on a digital output after the VI is stopped, i have a digital signal going from the error out on the daq in the while loop to the error in on the daq outside the while loop and a boolean going to the data of the daq outside, but i can t seemto get it to work

i attached the block diagram so you can have a look
Attachments:
PID Temp control.docx ‏120 KB

DIGITAL SIGNAL GENERATION

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