Generation of signal Pulse width modulation for ULx

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• With the help of modulated signal pulse width (square wave) to control when a signal is enabled or disable

  With the help of modulated signal pulse width (square wave) to control when a signal is enabled or disable

  Hello all

  I am using a modulated signal to labview created pulse width (square wave) to control when a signal is activated or not.

  Here is my logic and a concrete example:
  (1) the wave source signal is continuous
  (2) use a PWM (square wave) created in labview to control when the signal is enabled or disabled
  (3) if the PWM (amplitude) signal is superior to 0 play signal PWM is not greater than 0 do not play signal.

  I use actually this to the sequence step / pulse several distinct magnetic coils using my audio card (which has several channels of audio output), I have a signal in labview played constantly.  As to compare it to the PWM (square wave) which controls whether or not the signal is played on each separate channel.  That way I can control which coil is on and offshore and in what order they are activated.

  I couldn't find an edge detection for a square wave created in labview, so I tried the limits, but it doesn't seem to work unless I change the phase manually and it only goes 1-1.  I'm just trying to compare the PWM (edges of the square wave) already created by labview / play a signal if the pulse is greater than 0 and it shuts off the signal, if she is less than 0.

  Should I do this another way

  TIA

  A waveform contains an array of values. You must check every value and respond accordingly:

  

• Construction delays in pulse width modulation

  HI there I am trying to build a vi to control speed for a motor drive.

  The specification that the technician gave me is to produce a wave of modulation of width pulse with constant and variable gap time "punctually".

  This will give you the variable speed motor that can be manipulated.

  I have build a vi pulse width modulation, but I do not understand how the time constant of the ditch example 20ms while varying the time on 1 - 3ms.

  Is there a method I could use or an example I can look at? Any help will be doing thanks in advance.

  I'll join my current vi.

  For the most part, you just need to calculate some of the variable you use to leave on time and downtime.

  I don't know style.

• Impossible to find Pulse Width Modulation (FPGA, using SCTL)

  Hi all

  Can someone tell me where I can find Pulse Width Modulation (FPGA, using SCTL) .vi? I could not find in Finder example LabVIEW.

  Thank you

  Here it is...

• pulse width modulation

  What modules or do I need to acquire signals from an LVDT? I have an analog output, but is there another required module?

  ABC for an external power supply. According to the specifications of the signal conditioner box you need a power supply very stable and clean.

  CD to your analog input (+-10V?) of the cRIO.

  If possible use cable separate power and sensor power (try to avoid sharing the GND (C)) and if possible use the cRIO input differential.

• signal level for pulse width measurement

  Hello

  I am able the pulse width with the meter M6251 (CI pulse width)

  

  I understand that the digital input works on the TTL levels (0, low 8V 2, 4V high).

  Can you say exactly in which the level of signal pulse width is measured?

  Thank you

  Ralf

  In fact, the transition from low to high (or vice versa) is located in between 0.8V and 2.2V.  It is not specced exactly where it will be (although you'd be able to get a better idea, if you have an analog source, you can slowly increase until you see line status change).

  This is why the fast rise time are important to accurately measure the digital signals.

  Best regards

• pulse width of measurement of signals generated by data acquisition

  Finally, I would like to:
  Start a counter pulse width measurement and the analog output at the same instant.
  Stop the measurement with an external digital signal pulse width.

  My current plan is to use a digital output on the acquisition of data to synchronize a digital input and the start-up of the meter input.  The digital input will be a trigger to start for the analog output.  This works, except for the meter.

  While trying to implement this, I tried a simple test to generate a digital pulse with the acquisition of data and wiring for counter inputs.  It does not, even if it seems perfect to an oscilloscope.  Then, without changing the software at all, I connect a function generator to my counter entries, and it measures pulse flawless widths.

  I'm actually implemented it with a Python wrapper around the C DAQmx API, but I recreated in LabVIEW, and it has the same.  VI attached.  I have the latest drivers DAQmx.

  Accidentally, I posted this in a forum for LabVIEW, as I managed to post with the account of a colleague.  I think 2 ups live as this mandate to another post.  I'm sorry.  Former post is http://forums.ni.com/ni/board/message?board.id=170&message.id=389856.

  Solution: I had to set the channel to counter with implicit synchronization.  In addition, the sampsPerChanToAcquire must be at least 2, if not, there is an error.  I still don't understand why it worked with a source of external impulse, however.

  DAQmxCfgImplicitTiming (task_handle, DAQmx_Val_FiniteSamps, 2)

• Generate PWM signals with 1.5 ms pulse width

  Hi all

  I'm working on a project where I need to generate a PWM with a pulse between 1.3 and 1.7 width ms to order a servo rotation continues.  LabView is in communication with an arduino Uno microcontroller by LINX.  My original plan was to use the milliseconds of wait function in LabVIew to do this.  I put the PIN PWM high, wait 1.3 or 1.4 ms then set the low axis for 20 less ms pulsewidth.  before repeating.  This is how I have gnereate one using the Arduino IDE pulse width, so I thought I'd be able to do something similar here.  However, as I'm sure is already obvious to anyone who reads this, the milliseconds waiting finction in LabView only accepts the whole entries.  Arduino IDE is similar, but there is a delayMicrosecond function that can be used, so if I want 1.4 ms I use 1400 US snf then convert it in ms for the 20 least part.  How can I do something similar in LabView?   Also. When I run the program as what with a 1 ms pulsewidth I have a strange behavior.  It in fact generates a PWM signal, somewhere between 0.75 and 1.25 ms and with a period between 50 and 54 ms, it turns into a model each about half a second.  I'm using LabView 2014.  Any ideas?

  Chris

  You can't get that kind of resolution with Windows and any delay you specify will have considerable jitter due to Windows. If you can pass values with Linx and allows the arduino to control them, stick with that.

• sampling frequency of DAQ assistant for pulse width measurment

  Hi all. I want to measure the pulse width of a digital signal of about 1 kHz, via digital DAQ vi assistand pulse width. I need to measure the pulse width approximately 100 Hz.

  I put 1 sample on request and in one of the other method of as implicit synchronization for continuous measures that I met at the error. He doesn't let me frustrating that I could not measure a measurand jut at 100 hz.

  I use Daqmx and windows 7 sp1 and labview 2012.

  Thank you

  OK I have the solution, it's better to see the example and do not use daq assistand and use the primary functions.

  Counter-read Pulseand width and frequency .vi (continuous)

• -Measurement of the pulse width specifies the timeout?

  I'm trying to set up a simple project of Signal Express that measure the pulse of two separate signal lines width.

  My PCI6224 has two entrances of meter and then run each pulse in the entrance of a meter line, respectively.

  The I set up the express project signal attached, which consists of two simultaneously runnings tasks DAQmxAcquire.  Each of them is set to measure the pulse for one of the pulse width.  I then connect the results for further analysis.

  This configuration works very well from time to time.  The problem arises when the impulses do not arrive quickly enough and the acquisition of the timeout action.  Looks like that has a simple solution - just increase the time-out - but I can't find a single setting around the affects, the time-out!  The time-out period is always 10 seconds, regardless of what I do.

  Can anyone help?

  Thank you.

  Hello rothloup,

  Unfortunately, there is no option to change the time-out Signal Express for a task entry counter.  This has been brought to the attention of our developers.

  Reading a DAQmx LabVIEW VI has a time-out node you can specify the time-out period, even in the tasks of meter.  I suggest you try to implement your system in LabVIEW (if you can).

  Here is a tutorial on how to make PWM in LabVIEW.

  http://www.NI.com/Tutorial/2991/en/

  See you soon,.

• single pulse width measurement

  Hello

  I'm trying to measure the duration of a single pulse using ctr0 on an SMU-6361.

  The signal in the attachment Capture7.jpg, goes PFI 9, ctr0 door.

  The problem is that the counter see ' s the front up and stops. The pulse width is not given as can be seen in the output (Capture8.jpg).

  I get the same results by using Meas_Pulse_Width.vi example.

  Is something wrong with my SMU-6361?

  Oh, I think I know what it is.

  Change the task "pulse width" (a single pulse of height) instead of "Pulse" (the high and low time of a pulse repetition measures).  Change the DAQmx Read to use Ctr > single sample > DBL (instead of pulse).  Change the property filter node digital to use the corresponding properties of the "pulse width" (the filter is still necessary):

  

  The task of the pulse was not period initially because you receive a series of noise pulse repetition (and so it was a very low period).  With the filter, this time since the noise disappears now and the single pulse did not finish measuring the pulse (which requires a high and some time):

  

  For the record, I agree that it is confusing that there is the "pulse" and "Pulse" measure and they do different things.

  Best regards

• NI 9401 pulse width measurement.

  Hello

  I'm not sure that I understand very well the pinout diagram. At the present time, I have a NI9401 in a NI 9172 chassis.

  DIO0 and DIO1 are connected at the gates of light. I have an opto switch and I want to measure the pulse width when an object blocks passes through the slot. Can I use one of the other free entry of the for do?

  The entries are DIO2, DIO4 and DIO5.

  The other IO pins are used as triggers.

  See you soon

  K

  Hi Kamilan,

  If you explore in the measurement and Automation (MAX) and find your 9401, you can right click on the device and select "Pin of the device" which pulls up a window that says what features each pin on the device.  For example, according to this document, DIO2 is PFI2 to THE CTR0 CTR0 B and FREQ OUT.

  To answer your second question, do a right click on your device and create a new task for your 9401.  "You should do an acquisition of signals" counter input "pulse width and select CTR 1 on your device.  Once you do this, you can configure the parameters of your task and Max it will tell you where you need connect your signal source, which, for me, is DIO5.

  I would like to know how it works for you, thank you!

• Pulse width depends on the number of pulses (pci-6602)

  Hello

  I'm trying to generate samples done with pci-6602.

  I use CO Pulse ticks + implicit options

  External impulses is 1ms 1PPS pulse from the trimble GPS receiver

  If I set the number of pulses = 1, then I had to pulse length (high ticks - 1) =

  If I set the number of pulses > = 2 and low ticks > = 3, then I got pulse length = (high ticks)

  If I set the number of pulses > = 2 and low ticks = 2, then I got last puls width = (high ticks - 1) and all other vegetables dry with length = (high ticks)

  With a single generation pulse width pulse is (high ticks - 1)

  Is there an option to configure the same pulse width for any number of pulses for a train over (N pulse)

  screens to fix

  
  

• Addition of a generation of finite pulse delay generates the error-200305

  Hello

  Sorry, I'm relatively new to the generation of pulses. Please help me understand why I get an error-200305 in my example VI Test Pulse Generation.vi when you specify an initial period. Other than the creation of a task and giving it a name, the code looks the same for me as the code in the example LabVIEW Gen dig Pulse Train - finished - Dig Start.vi comes with LabVIEW. When I enter the same settings in Gen dig Pulse Train - finished - Dig Start.vi, I do not get this error. What could happen?

  I use a DAQ OR-PCI-6031E map on a 64-bit Win7Pro and am under LabVIEW 2011 (64-bit).

  Thank you for your help and forgive me for a perhaps trivial question.

  Peter

  Hi pbuerki,

  I tried the 2 screws you attached and found that if you replicate math you used in "Generation of Test pulses" for entries of the example VI, VI example will give you the same error. I think your VI and the example behaves exactly the same way.

  However, I found a solution for this error. I tried this on a simulated device, but I think this should work for your physical device as well. For your DAQ card, he sometimes give you the error at very low frequencies because the default driver is the basis of time of 20 MHz and for some combinations of frequency and the number of pulses, the time base produced more ticks than the counter can handle. To work around this problem, you need to use a DAQmx channel property node. You will need to use the CO. Channel CtrTimebaseSrc property to set the time base to be DevX/100kHzTimebase. You must activate the setting 'Understand the advanced terminals' in the name of I/O filtering to find. This change should fix your error.

• How can I use two counters simultaneously to pulse width measurment

  Hello, everyone!

  I'm new to Labview. I currently have some cDAQ9171 and width measurment with 9401 impulses. My understanding is that the 9401 was 4 meters, which means that I can use these meter separately. However I have the following problem.

  1. I use ctr 0 and ctr 1 (PFI 1 and PFI5) to measure two different impulses. However, it seems that there is an interference between two counters. How can I make two counters working simultaneously and separately?

  2. I first try a pulse width measurment counter in Labview signalExpress. My pulse width is about 0.4ms. However, I can't get the right result, if I choose the starting edge is on the rise (the results always around 20ns. Only if I revise my pulse and pick the starting edge is down, I can get reliable results.

  I'm confused about these issues for about 3 weeks... Is there someone can help what can I do with that?

  I have attached a simple vi...

  Thank you very much!