Counter/Timer topics

I am getting 89132 while using 6602

Ashish_Paralikar — Fri, 24 May 2013 09:25:46 GMT

Hi,

I am using daqmx utility for Linux for generating pulse train on all the channels.

When I am generating a square wave on ctro and ctr1, I am not getting any error.

After I tried to generate the same pulse on others from ctr2 to ctr7, it is popping up an error which is as follows:

Error -89132 occurred at Test Panels

Possible reason(s):

Specified Property Value can not be used, because it requires resources that are currently in use.

Property: CO.Pulse.Term

Destination Device: Dev1

Please help me with this issue.

Regards,

Ashish

What is error 50103? at DAQmx START task?

dav2010 — Wed, 22 May 2013 02:38:31 GMT

Hi,

I am using cDAQ 9174 with NI 9401 to measure encoder period. I have two encoders, and learned that I need to have a separate task for each. Initially, I got an error telling me that the task was not reserved, so, I followed the forum board and added the DAQmx CONTROL TASK, set to RESERVE. That eliminated the error, but, now I get a new error 50103, which provides very little detail about what the error actually is. The attached is a snippet of the code, where you see there are three tasks, two counter tasks to measure encoder period, and one voltage measurement task, which I believe is unrelated to this error.

Error 50103 occurred at DAQmx Control TAsk.vi:3.

Possible reasons: NI Platform Services: T/he specified resource is reserved. the operation could not be completed as specified.

Taks Name: _unnamed Task <3E>

So, initially, it was telling to reserve the task, now it is telling me that the problem is the reserve. Does anybody know what this error is about? The attached code is connected to a WHILE loop that is intended to do a bunch of stuff with the period data after it is collected.

Thanks,

Dave

how to measure rpm

Eluan — Mon, 20 May 2013 21:09:15 GMT

I have an NI 9401, labview 8.6 and a 9172 chassis and I am trying to measure the rpm of my rotating shaft. The code I wrote works at low speeds but is not accurate at high speeds. Does anyone have a standard labview 8.6 code for obtaining the angular velocity of a rotating object?

6014 board problems with counter 0

pizzata80 — Sat, 18 May 2013 11:28:15 GMT

Hi all,

I'm working on a project with a 6014 board and Real-Time Windows Target of Matlab. I need to interface the signals from two incremental encoders. The qudrature signals are converted into a direction signal and a pulse train signal with the idea to feed them to the counters of the board, configured as bidirectional counters in up/down mode. The connections are as follows:

For Counter 0 - the pulse train signal is fed to PFI8, and the direction signal to DIO6.

For Counter 1 - pulse train signal to PFI3, direction signal to DIO7.

The problem is that Counter 1 is working properly, while with the same signals fed to Counter 0 what I read makes no sense. The counter increments by very large values at once and behaves erraticaly.

I'm seeing this behavior on two different boards.

Any help please!

Thanks in advance!

Stanislav

measurement digial input or analog input

daadmaster@gmail.com — Sat, 18 May 2013 09:02:20 GMT

Hello,

I am trying to measure frequency using NI DAQmx task and then convert this to an RPM if at all possible.

I have the following hardware .

I have NI DAQ-9174 with the DI (NI 9421) modules (8 channels)

I have wired the proximity sensor and tachometer to ai0 and ai1 respectively which is PFI 1 and PFI 5 among these 8 channels in order to measure (pulse ,frequency , or periods) .

What I am trying to do is to somehow convert this digital measurement into a RPM by using the DI module.

If not possible using the DI module, can I use AI module (NI 9229) in order to convert this analog measurement into a RPM.

Any help would be appreciated.

Mola

Test Engineer

Sampling rate of Pressure sensor

Jango — Fri, 17 May 2013 21:13:42 GMT

The code attached shows an encoder triggering the pressure sensor on A pulse. Encoder has 1000pulse per rev. I am able to trigger the sensor, but I finding it dificult to sample it with respect to the encoder. I am assuming the Pressure sensor (Mod 6 ai0) acquires data with respect to the loop. I wish to have the sensor acquire data with respect to the encoder A pulse.
Can someone suggest me something?

Encoder-http://www.automationdirect.com/static/specs/encoderld.pdf

Omega Pressure sensor- PX309200G5V

Thanks,

Counter Out task, initial delay, and commit

jonasz — Fri, 17 May 2013 18:00:51 GMT

I don't know whether it's a bug, a feature, or me not understanding how to do things correctly.

I create a counter-out task with DAQmxCreateCOPulseChanTime, with an initial delay. Then I set DAQmxTaskControl(stimOutTaskHandle, DAQmx_Val_Task_Commit).

When I now start the task, I don't get the initial delay, but the rest of the pulse looks like desired. If I do not commit the task, the delay is as expected.

Onboard Timing with Daqmx on PCI 6132

TVG — Thu, 16 May 2013 08:19:26 GMT

Hello,

My collegue and I are trying to make a program in Labview 2012 that starts a timer when the first trigger(sensor) is hit and stops the timer when the second trigger(sensor) is hit. We currently have a program for it, but this program was not accurate enough. Also the current program is using the DAQ assistant, but we would like to replace this with daqmx triggering. We also tried to use the OnboardClock on the PCI 6132, but still could not make the program work.

Is there someone that knows how to do this and could explain it?

(In the attachment is the current program)

Thanks in advance,

Tommy van Geest

pulse train from encoder

Eluan — Wed, 15 May 2013 19:16:30 GMT

Hi,

I am attempting to generate a pulse train to trigger a camera using an X4 quadrature encoder with A, B and Z index, the Ni 9401 and the NI 9172 chassis. My encoder generates 2500 pulses per revolution but I need a pulse train of 5 pulses every revolution to capture 5 images evenly spaced on my rotor. I want to capture these five locations for every revolution. Any help would be greatly appreciated

Counter output, on demand

jonasz — Wed, 15 May 2013 00:46:24 GMT

I'd like to have a counter output a single pulse whenever a condition occurs within a loop. My current solution (in pseudocode; I use LabWindows CVI on a RT target) looks like this:

DAQmxCreateTask(...);
DAQmxCreateCOPulseChanTime(...);
while (true)
{
  if (condition)
  {
    t1 = Timer();
    DAQmxStartTask(...);
    t2 = Timer() ;
    DAQmxErrChk (DAQmxWaitUntilTaskDone(*th,2));
    DAQmxErrChk (DAQmxStopTask(*th));
  }
}
DAQmxClearTask(...);

Unfortunately, the delay between t1 and t2 is at least 0.142ms, and sometimes 2ms. Is there an elegant way to decrease this and not having to call StartTask again and again?

Thanks,

Jonas

Syncronizing based on CO, retriggerable

Telleurium — Fri, 10 May 2013 20:40:34 GMT

I would like to synchronize AI, AO and DO finite tasks that are retriggerable based on a CO pulse train. I have set up a CO Pulse Freq task to run off ctr3 of my 9178 chassis. The rising edge triggers the AO to start, the falling edge triggers the AI and DO to start. Provided these finite tasks are short enough they should be retriggerable, thus each time my CO sends a pulse they should restart.

Having trouble making this work, get an error that the AI task is not retriggerable (using 9222). Can anyone provide guidelines on how to set such a scheme up?

Gracias.

start acquisition at a certain time, and for a certain time

Shuichi-kun — Wed, 08 May 2013 02:51:42 GMT

Hi every one,

I want to start the acquisition every ten minutes for 30 second each.

I thought about the while loop and timers but I'm not experienced enough to know how to do it.

Labview 2009, please help me.

low cost sampling rate

Laptopolus — Thu, 02 May 2013 20:48:56 GMT

I am currently using a usb 6008 to generate a pulse train. I seem to be able to generate it at 200Hz. What other hardware is availibe to do this?

The usb 6210 will do this by using one of the counters to tigger a digitial output high/low at a given freqency? I simulated the hardware in Measurement and Automation and it let me set frequency, but can you do something like give it a pulse train of 400 "steps" at a given frequency and have it complete?

Can I source both counters at the same time (I do not need them to be sync) ? It says they can do 80MHz, is this correct. I only need about 300kHz.

pci 5154 sampling rate

gbhaha — Mon, 29 Apr 2013 20:33:08 GMT

Hello,

What is the max sampling rate of PCI 5154 for two channel inputs? The manual indicates the 2GS/s is for a single channel only. Then, am I not able to get a 1GHz bandwidth for simultaneous two channel measurements? Thank you!

Niveaux de tension entré carte PXI-6602

Tech_wind — Mon, 29 Apr 2013 20:01:03 GMT

J'ai 108 délais de temps (un trigger et 108 signaux différents...) à mesurer (14 cartes PXI-6602). Je voudrais enlever un boitier ``buffer`` avec optocoupler entre signal et PXI (enlever une source de problème...)

Signaux d'entré #1 entre 12 et 14 volts durées 4 micro seconde

Signaux envoyé au #2 PXI Impulsion basse de 3.8 volts à 200millivolts...

Questions si j'envoi le signal #1 directement sur les entrés de la carte PXI-6602 (selon les specs Les entrés digital sont compatibles TTL-CMOS) et sur une autre doc il mentionne 5.25 volts max...

J'ai inclus un image de l'oscilloscope.

Cette question est relié a une demande de soutien (#7374210) que j'ai du abandonner le mois passé (urgence sur un autre projet)...

error 200329 reoccurring

Crashdx — Fri, 26 Apr 2013 20:57:13 GMT

I've been having an issue with getting error 200329 for my analog input into my NI Elvis board. The first time I got the error I left and came back to my Labview program the next day and the error had disappeared and it worked fine. After about 3 days the error came back and I couldn't get the error to leave. So I switched out the board in the computer for a different one and the error went away and it was working fine again. Another 2 days later the same error 200329 has shown up and I can't get it to leave. There has to be a better way than constantly swapping out new boards to fix this problem.

I've attached the code that I have been running and testing with.

NI-6602 acquistion delay and buffer overflow

jl694 — Wed, 24 Apr 2013 12:13:07 GMT

Hi everyone,

I am using a NI PCI-6602 to record photon arrival times. Basically, it counts the number of rising edges on the 80MHz sample clock that occur between two rising
edges on the photon TTL signal. The array of integers can be converted to times by multiplying by 12.5ns. Please find my VI for the task and its subVI attached.

I have two problems:
1) I want to do this same measurement for two photon detector channels. I have set up two independent channels. My aim is to correlate the signals with a delay between them. I am able to implement a delay in the software, but from my data there appears to be a small inherent delay between the start of each channel.
The amount of delay is seemingly random and occurs in both the positive and negative direction. In the VI I have attached, I tried using the Arm Start Trigger in order to get both channels to start acquisition at the same time, but while this reduced the severity of the delay, it has not removed it completely. There is still a delay of between 1 and 500 microseconds. Have I implemented the Arm Start Trigger correctly, or is there another way to go about solving this?

2) I regularly receive an error stating that "data was overwritten before it could be read by the system". The number of samples that has been collected before this error varies wildly and also varies between the counters on the board. I had a theory that the sample transfer rate was not good enough, but according to the manual, the transfer rate should be about 2000kS/s. This is more than enough considering that the photon count rate is less than 50k/s. The PC I'm using has a PCI graphics card too. Is it possible that this is limiting the sampling rate? Here are the PC specs: Intel Pentium D processor (3.0GHz), 2GB RAM, nVidia GeForce 7300 LE graphics card.

Thanks in advance.

synchronized counting

Henok — Wed, 24 Apr 2013 08:53:15 GMT

Hello everyone!

I have the following at hand:

I am working with NI PXIe-6361 X series Multifunctional DAQ and to it is connected SCB-68 I/O box. I also have TDC (sync) and CAD pulses from a testbench engine, which I would like to connect to the I/O box and do a synchronized edge counting of the CAD pulse. For example if I have 360 pulses of CAD in between two TDC pulses, I'd like to count from 0 upwards to 360 from the first detection of TDC pulse. How can I come across this problem I am facing? Which help examples are also good to start looking at?

Thanks

/Henok

660x weak pull-down resistor schematic

sam.broyles — Mon, 22 Apr 2013 21:24:20 GMT

The 660x spec sheet mentions that the Power-on state has a Input (high-Z) with weak pull-downs, but I cannot find a schematic with this weak pull-down resistor value.

I want to measure a clock signal on my DUT without loading or distorting the signal, so I plan to use a buffer. I'm concerned about the required drive current to overcome the built-in pull down resistors and the resulting threshold requirements of my PXI-6608 counter.

If anyone has a link to recommended buffers, level shifters, or a knowledge base article with an example circuit, it would be much appreciated!!

http://www.ni.com/pdf/manuals/372141b.pdf

How to reset counter with each iteration and how to introduce a delay

Peluche — Fri, 19 Apr 2013 17:44:46 GMT

Hi everyone,

First I apologize for the basic level of my questions, I am very new with Labview...

I am reading counts off of a USB-6008 labview chip using the DAQ assistant and I write the output to a file. The problem is that instead of giving me the number of counts for each iteration it gives me the sum of it all. How do I make the DAQ assistant reset to 0 counts on every iteration? I tried using a shift register but it just adds a counter to my file and nothing else...

Thanks a lot