Using PXI 6251 counter to delay a trigger on PXI

Hi at all,
I need to synchronize some devices on an PXI chassis. Basic operation is a user waveform generation on a PXI5401 that routes the Trigger Signal for the generation to one of the PXI (RTSI) lines. I'd like to use this trigger signal to start a counter on a PXI 6251 counting the PXI 10MHz Clock. No problem so far ( at least none that I see What I need is a possibilty to set another sync signal as soon as a certain counter value is reached in order to use this signal as a delayed trigger signal. Is it possible? And how? I've taken a look at the LabVIEW Example finder, but haven't found an example yet...
Thanks!
Oli
P.S. Using LabVIEW 7.1.1, NIDAQ7.4 and a PXI 1042 via MXI4
Programming languages don't create bad code, programmers create bad code....

Nathan,
Thanks for your excellent solution. I'm ordering the Aux100 cable (9-Pin DIN to two BNC Female) to export the trigger signal from the PXI to the Device_2. I will test the program (Echo_Mode_PXI_5122.vi) to be sure it will be suitable for my application.
Another problem, when my system is working on ultrasound Pulse-echo mode (Pulse_Echo_Mode_PXI_5122.vi), the input trigger must be set a delayed trigger acquisition (by setting the trigger delay to, for example 3µs) to remove the signal of power source. Could you please tell me how I can configure the digitizer in this case?
Regards,
John C.
Attachments:
Echo_Mode_PXI_5122.vi ‏49 KB
Pulse_Echo_Mode_PXI_5122.vi ‏49 KB

Similar Messages

How do I generate two finite pulse trains using counters on PXI-6251

I'm trying to use Counter 0 and Counter 1 on the PXI-6251 to generate two finite pulse trains. But, I get this error: "The specified resource is reserved. The operation could not be completed as specified." See attached example.
Inside the disabled box is what I'd like to run on both counters. I stripped things down to creating the task, starting, and stopping. I then started to add things to see what my problem was. The timing VI seems to be what causes me issues but I don't know why.
My end objective is two identical pulse trains with one delayed by 5us, which I figured would be easy to do in the initial delay. I tried both in a single task and as separate tasks with no avail.
Attachments:
2_counter_outputs.vi ‏32 KB

Hi SirMutt,
Creating a finite pulse train requires
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What you want to do is correlated DIO. I’ve
done a search on our website for “correlated DIO” and have come up with a few
resources. Hopefully that will help you get started.
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I am on a project at work where I need to verify the speed (in RPM) of an unloaded motor which can operate up to 1400 rpm. After doing some research, i determined that a quadrature encoder could be used to make the measurement. I am looking at this encoder http://sine.ni.com/nips/cds/view/p/lang/en/nid/205321.
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Hello jwins,
The PXIe-1075 is a multi-segment chassis and the PXI trigger bus is split between each segment. The figure in page 17 of the PXIe-1075 user manual (http://www.ni.com/pdf/manuals/372537b.pdf) shows this.
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6251 Counter input signal

Hello,
I am acquiring pulses which are 0-5V with the counter of the PXI 6251. However, I would like to know if it is possible to acquire pulses that are, for example 0-12V or 0-24V without damage the device. In other words, which is the voltage range for the counter input in a PXI 6251?
thanking in advance,
CJMV

Hi,
You will not be able to use the counter directly but you can setup an analog level trigger for your signals. This will create a pulse that isTTL compatible for you everytime the signal crosses a particular level. Then you can route this into your counter and perform any counter measurements on it. An example is this is shown here where it sets up a level trigger to make frequency measurements.
Alternatively you can purchase an industrial strength digital I/O board such as the USB-6525 but this does not include a counter.
Please let me know if this works out for you.
Message Edited by Abhinav T on 07-06-2007 05:20 AM
Abhinav T.
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NI PXI 6251 strange behaviour

Hi,
I have couple of questiobns about NI PXI 6251 in PXI-1045(with pxi-8360 Mxi-express controller).
First it works with some huge delays when Daq_mx_stop is called or even the vi is stopped by RED button
Second The reference trigger is not working for me...
When the simple start trigger is set anf APFI0 is used everythzing works fine (except previously described lond delay)
But if I set reference trigger it do not react on the triger pulse.
thanks in advance

Hi,
Unfortunately the problem is not solved.
This behaviour is observed not only in my .vi but also in NI MAX when I create a task there.
If I use start trigger option acqusition works with external trigger, but DAQ-assistent shows me a warning: 200010 (not all points are acquired or generetaed )
Long delay before the task finishing occures here as well.
If I try to config reference trigger for the same input (APFI0) with the same parmeters it also reacts on a trigger but no data is read and DAQ-assistent shows me an error: -200281.
Also a long (~15sec) delay is observed before the task in NI MAX is finished comletely.
In attachment I've add an example where I have all these troubles but it is nothing else as very basic read example I have the same problems also in standart example from NI library.
Thanks in advance.
Attachments:
testpxi6251.vi ‏31 KB

How can I set up a delayed analog trigger on PCI 6115 DAQ

I have an S-Series PCI 6115 DAQ which I’m running with Labview. I’m using it to measure signals from an acoustic emission sensor and two force transducers. I’d like to set up a delayed analog trigger which will start acquisition on all three channels a period of time after a selected channel’s voltage exceeds a threshold.
Currently I’m using the AI Config VI in line with the AI Start VI and AI Read VI to capture data after a analog hardware trigger occurs. A software trigger probably wouldn't work because I have to sample my data at 10MS/sec. My setup works fine for triggering without any delay or skip counts. However, if I set the delay or skip count in the additional trigger parameter field of the AI start VI, there is no effect, and the device still starts capturing data immediately after the trigger is received. What is the cause of this, and how can I get around it?
Also, is it possible to sample the channels of a PCI-6115 DAQ at different rates? Right now, I’m sampling all my channels at 10MS/sec and throwing away data on all channels except one. However, this seems relatively slow and eventually I would like to attempt pseudo-real time control using my data.

rpursley8 is right about needing to get the counters involved if you want a hardware timed delay in your application.
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I need to create a time controlled boolean.
For example a digital line is set to False. I'd like to change to True status for a certain amount of time (e.g. 150ms).
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Thanks

Hi,
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Repetative trigger from PXI-6733 to PXI-6220

I am running a PXI-6733 in continuous mode and want to send a trigger pulse from the 6733 to a PXI-6220 at the start of each cycle. I will also want to do this in finite sample mode. I have used a DAQmx Connect Terminals VI to connect the trigger channels. But I cannot find how to set the 6733 StartTrigger as an output or how to synchronize it with the analog output. Any suggestions would be welcome.
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Attachments:
6733 Correlated AO and DO.vi ‏66 KB

How to use on board counter to change sample rate dynamically on pci-6134

Hi,
I am relatively new in LabView.
I am making power quality measurement system and I need to vary the sampling rate of my pci-6134 dynamically (all channels simultaneously). What I need is to have a constant amount of samples in each period of measured signal (grid voltage), which changes slightly all the time. Therefore I will have to measure the voltage, find its exact frequency and then adjust the sampling rate of daq accordingly. I know that there will always be some delay, but I would rather like not to go into any predictive algorithms...
I have found an information in the Forum that one of possible solutions is to use an onboard counter to change the sampling frequency but I have no idea how to make that. Can someone help me or possibly show an example?
Is there a simple way to solve that problem?
Thanks in advance
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At least at a glance, the code generally looks like it ought to work. Two thoughts:
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P.S. Bonus 3rd thought. I just went back to reread the thread more carefully, including your first screenshot. I'm now thinking that maybe the hardware actually WAS behaving properly, and that you just weren't aware of it. When you query the AI task for it's sampling rate, all the task can know is whatever rate you told it when you configured it outside the loop. So even as you change the counter freq to change the actual hardware sampling rate on the fly, the AI task will continue to report its orig freq. After all, how is *it* supposed to know?
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How to generate a pulse of 5 V -ve polarity in synchronisation with a 10 v input using PCI 6251 DAQ board

HI
I want to generate a 5V -ve polarity pulse to trigger my IEEE 1394 camera using an PCI 6251 (scb68 pin E) device, furthermore I am reading a standard Vsync signal from a SVGA port which is 10 v.
Now I want to synchronise the image capture of an IEEE 1394 camera with the Vsync signal so that camera is triggered to capture at every 4th Vsync signal (which is 50HZ.). Presently I am able to read the Vsync signal and also generate the -5 v signal But the Daq board generates a continues -5v signal while I want a 1 ms pulse (for every 4th Vsync).
Also this 5 v signal is generated even if the vi is stopped running.
Can anybody guide me so this problem can be solved.
Thanks a lot in advance
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You can use the Write function, that is you can use the 10 volt signal as a trigger for the task, and when you get this trigger, the task starts and generate (writes) a waveform you defined in an array ("data", in the example).
Something like this..
DAQmxCreateTask("",&taskHandle);
DAQmxCreateAOVoltageChan (taskHandle, clokSource, your_sampling_freq, -10.0, 10.0,
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DAQmxWriteAnalogF64 (taskHandle, 1000, 0, 10.0,
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DAQmxStartTask(taskHandle);
// and then you create a loop....
For example you can specify data to be like this:
data[0] = -5;
for(i=1;i<1000; i++){
data[i] = 0;
Tell me if you need more help.....
bye

Using more than one time delay in a thread

Hello,
I need to use two non-consecutive time delays in a thread. My thread typically proceeds as follows:
1. Tell an oriel MS257 to change wavelengths
2. Time delay #1 to give the MS257 time to change
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Thanks,
Ying
Solved!
Go to Solution.
Attachments:
TFTmeasure.vi ‏115 KB

Looking into the sources show: Cleanup is a nice tool (even thought it is far from perfect )
Well, nevertheless, from the wireworking, it seems alright that the second Time Delay express VI should indeed wait for the loop to finish. Therefore, i am wondering why it is skipped. And the only reasonable explanation: You have an error on the error cluster.
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hope this helps,
Norbert
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

PXI-6251 Phase Angle

Good Day,
I am currently using a PXI-6251 module and I need to measure Phase Angle between two sinusoidal waveforms. I have done a lot of searching and can not find much. If anyone is able to help I would appreciate it.
TIA,
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Hi TomJr-
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The easiest way to accomplish this is to query the AI.Convert.Rate propery as shown below.
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Hopefully this helps-
Message Edited by Tom W [DE] on 03-06-2006 01:15 PM
Tom W
National Instruments
Attachments:
untitled.GIF ‏3 KB

WANTED: NI PXI-6602 counter/timer

I'm looking to buy a used NI PXI-6602 counter/timer board. Got one?

"Zvezdana S." wrote in message
news:[email protected]..
> Hugh,
> To possibly obtain an used board from National Instruments, you should
> contact your regional Internal Sales Representative (ISR) for possible
> used boards. If you are not sure who your ISR is, generate a service
> request at:
I never knew NI had an SRQ line we could pull.
Craig Graham
Physicist/Labview Programmer
Lancaster University, UK

NI PXI 6251 SPI emulation

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I'd like to use NI PXI 6251 DIO to setup and run an SPI communication using Labview2013. Is it possible, do you have any suggestion?
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use the right hardware http://sine.ni.com/nips/cds/view/p/lang/en/nid/202368
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Using PXI 6251 counter to delay a trigger on PXI

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