Quantcast
Channel: Digital I/O topics
Viewing all 2182 articles
Browse latest View live
↧

HSDIO-6556 Low Range Current Measurements

May 10, 2016, 6:03 am
$
0
0

Hello All,

 

We use a PXIe6556-HSDIO. We are trying to measure the leakage current of a device at particular pin by applying 3.3V and measuring the current drawn by the pin.

Our observation is that the current measurement accuracy was worse than 10%.

On replacing the DUT pin with a known resistor value (with other end connected to a different channel configured to sink the current), we observe that only if the sinking channel is forcing a 1V instead of 0V. Measured values are in the table attached.

We also came upon the graph of Quadrant behaviour ## in the 6556 specification sheet (attached). Could someone please explain this graph? We believe that the sinking channel voltage variation improving accuracy is due to this quadrant behaviour, please help.

 

Thanks.

 

↧
Search

PXIe 5644 Digital I/O Setup

May 11, 2016, 7:43 am
$
0
0

Hi,

I am new to LabView and I am struggling to access the Digital I/O port on the PXIe-5644R. I have tried to access it with the following methods:

  • I tried to use FPGA Module. I installed the evaluation version to test it. I went through the setup process but it never showed up on my functions palette and I'm not sure how to access the module at all. I aslo don't know if I need the Real Time Module and I think I have the NIRIO drivers already but I'm not sure how to check.
  • I tried to use FPGA Interface which I already had downloaded previously and had access to its palette. The issue with that is it said it was missing support files [actual error: "target support for selectec FPGA device is not installed"] so I tried to find the support files, and I found the 2012 version [http://www.ni.com/download/ni-labview-2012-support-for-ni-pxie-5644r-1.0/3439/en/]. It didn't work because the version of LabView I'm running is 2015 SP1.
  • I have tried VISA as well but previously I had the issue with not recognizing the card. Thankfully, now NI-MAX can find the card but can't make out the port for some reason. Is there a manual way to get it to find the desired port as it does for COM1 and LPT1?
  • I also looked into Port I/O because I wanted to access specific pins but I don't want to waste more time downloading if there are other ways.

I am running out of ideas. I tried searching everywhere for more information inlcuding the forums, the examples, the manuals, and various Google links. My final goal is to be able to send out 0V or 5V out of select pins from the Digial I/O port.

 

This is all the information I have on the device, the port, and the software:

↧
↧

Outputting a pulse train and reading pulse width using NI myDAQ

May 11, 2016, 9:03 am
$
0
0

I'm having some problems outputting a pulse train and reading pulse width. When attempting to do this I am using "CRT 0"(as it is my only option) for both my counter and physical channel when I attempt to run the code I recive an error that says. 

 

"Possible reason(s):
 
The specified resource is reserved. The operation could not be completed as specified.
 
Task Name: _unnamedTask<8EB5>"
 
I'm not sure if this means that I cannout use CRT 0 for both my wave ceation and measurement  even though they use diffrent physical channels(DIO 1 for the width and DIO 3 for the train). Any help with this would be great.
Thanks, Ryan
↧

USB-6509 negative voltage input

May 12, 2016, 12:56 pm
$
0
0

how will the USB-6509 respond if a - 5 VDC signal is input to the DIGIO?  will it be interpreted as a 0?  Will the -5VDC damage the logic in the USB6509?

 

↧

1776c I/O communication

May 13, 2016, 2:58 am
$
0
0

hello everyone am working lately on an inspection project using 1776C smart camera  and for that i will need to commnicate with the camera using it's digital I/O so i was wondering if i can send it a 5V signal , would it be considered , coz am working with a microcontroller using 5v power supply , or i mst add an amplifier to get the value to 24v , thanks you 

↧
↧

running fpga vi from host vi issues

May 15, 2016, 2:32 am
$
0
0
Hi..
I am using flexrio system with fpga 7962R and adaptor module 6587.
I am trying to run the host vi for data generation from a file on host for my test board.

The problem is when I run the generation host vi with embedded fpga vi( checking run fpga vi, dynamic run), it does not work on first attempt. each time i have to run the fpga vi along with host vi. then stop both of them and run the host vi which results in the flow of data to the dma fifo on fpga vi. why is it so? how can I make the fpga vi tun in one go from the host vi?
Note: My other acquisition program is working fine. The problem is with data generation.
↧

16 USB-6509s on one hub?

May 16, 2016, 2:26 pm
$
0
0

Hello,

 

We are currently running 16 NI-6509 DAQ PCI cards in a SuperLogics computer with a 16-slot PCI backplane running Red Hat Linux. Because 16-slot PCI machines are not common we were wondering if could convert to the USB version of the 6509 and use a more common machine to control them. One of the things these boards do is measure tachometer pulses on rack cooling fans. So each of the 16 boards polls its tachometer every 2 milliseconds. All 16 USB-6509s would have to run from the same computer/hub.


My question is would this work? 16 USB-6509s, all on the same USB hub and each polling their tachometers every 2 milliseconds?

 

Thank you,


Kevin Ryan
Software Engineer
National Radio Astronomy Observatory

↧

Can I Use a USB-6501 in place of a PCI-6503?

May 16, 2016, 2:59 pm
$
0
0

I am currently using a PCI-6503 DIO Card in a Windows XP system. We are running an older version (7.1) of LabVIEW. We are trying a Virtual Machine under Windows 7, but it will not communicate with the PCI Bus. We are currently using a PCI-6503. Will a USB 6501 work in place of it?

↧
Search

8452 streaming API change chip select

May 17, 2016, 12:59 pm
$
0
0

Hi,

 

I am able to stream a command successfully using the streaming API.  However, it the default is CS=0.  How do you change and use the other chip selects?   I want to be able to select CS0 to CS7.

 

Thanks,

 

Bob

↧
↧

[Digital Output Problem] PCI-DIO-96

May 20, 2016, 9:50 am
$
0
0

I am using a NI I/0 card (PCI-DIO-96) with DAQmx libraries under Linux.

 

I compiled and run the example WriteDigChan.c.

 

After i run this example, i used a multimeter to measure the voltage at each line and check if the card is working properly.

 

The problem is that when a line is set to logic low (0) the voltage i measure is ~4,916 Volts and when a line is set logic high (1) the voltage i measure is 0 Volts.

 

Shouldn't be viseversa? Or am I missing something?

 

↧

USB-8452 skew between CS lines

May 23, 2016, 3:52 pm
$
0
0

I am using an NI USB-8452 to control a device using a 5 wire SPI using the SPI scripting capability. 

 

I want to be able to generate a trigger signal on one of the other chip select lines (CS) that occurs at the same time as the rising edge of my CS signal. However, there seems to be a huge amount of skew between CS0 and CS7.  For example, part of the SPI script executes:

 

fRet += self._lspi.ni845xSpiScriptCSHigh(self._cHdlScr, c.c_uint32(iCSB))
fRet += self._lspi.ni845xSpiScriptCSHigh(self._cHdlScr, c.c_uint32(iTRG))

 

where iCSB=0 and iTRG=7 (i.e. I want CS0 and CS7 to go high at the same time).

 

Is there a means to do this with the NI-8452?

 

Thanks

 

 

↧

How can I capture a hardware trigger (5.76 V, 25ns wide) and use that to trigger something else in LabView

May 26, 2016, 11:56 am
$
0
0

Hi there,

 

I am trying to synchronize data acquisition between two different instruments using LabView.

 

One instrument will be operating independently (it can't be integrated with LabVIew for a number of reasons), and the timing signal from that instrument which I want to use (5.76 V square pulse, 25 ns wide, occurs aperiodically) is 'extracted' (I made a breakout box and have the timing signal on a coax which I can plug into anything).

 

I want to take that timing signal and use it to trigger some event in LabView (the second instrument is controlled with LabView). 

 

I had hoped that a USB 6501 would be able to do the trick, but I realize now that it can't see a signal which is so short (I think).

 

So what should I do? How can I make LabView 'see' such a narrow pulse and use that to trigger some event?

 

In summary:

  • Have digital signal coming from a piece of hardware on a coax - 5.76 V rectangular pulse, 25ns wide, occurs randomly nut not more often than every ms
  • Want to input that digital signal into my PC and LabView where I will use that signal to trigger an event (in this case, start a data acquisition event on a different piece of hardware which is controlled with LabView)
  • I am using LabView 2013 64 bit, Windows 7x64
  • I was hoping to use NI-USB 6501 but I'm not sure it is possible since pulse is so narrow
  • A photo of the timing signal as seen on a scope is attached (note there is a tiny bit of ringing which won't be present when I fix the cable)

Thanks,

Sabrina

↧

How to set tristate logic using NI-DAQ 6212 in C#

May 26, 2016, 1:55 pm
↧
↧

Using the USB 6501 to trigger the execution of some code

May 28, 2016, 1:46 pm
$
0
0

Hi there,

 

I would like to use the USB 6501 to trigger the execution of some code. I am struggling to figure out a way to do this because all of the examples I can find use a daq to trigger acquisition on the same device - I don't want to use the 6501 to do anything except see the trigger and then I want to execute code which doesn't use any daqmx vi's.

 

To be more clear, here is what I would like to do:

  • I have a 1.5us wide, 5.25 V high TTL pulse coming from an instrument. The pulse arrives at a regular interval, with the interval varying between 10ms and 100 ms. (My 'data rate', so to speak, is not large at all. Also, I can control that interval so I can make it longer if I need to).
  • I want to detect that pulse with the USB 6501
  • I want to use some of NI's digital i/o vi's to 'see' the pulse and then use that pulse as a trigger to execute a block of code 
  • The block of code which will be executed controls a different instrument, it does not use any daqmx vi's, and is not a NI daq device.

I am confused about a few things:

  1. Does the USB 6501 have the capacity to see a 1.5us wide pulse? I can't find any specs for minimum pulse width except with the counter input. In other words, does the USB 6501 have a high enough clock speed to see a 1.5 us pulse?
  2. How will I implement the timing? The block of code I want to execute will take much less than 10ms to complete, but I am confused about using the timing functions to ensure the block of code executes within the interval between pulses
  3. How will I implement this generally? All of the examples I can find are about using pulses to trigger acquisition on a DAQ. I can't find any examples for just triggering some block of code.

Thanks so much!

Sabrina.

↧

Carte NIPCI 6518

May 31, 2016, 4:55 pm
$
0
0

Bonjour, 

je suis à la recherche du composants de la carte NIPCI 6518: taille de mémoire, type de mémoire...

et est ce que la carte NIPCI 6518 contient un FPGA ?

Merci 

↧
Search

How to set digital output at CVS-1459RT

June 1, 2016, 11:30 pm
$
0
0

Hello,

 

how can I set a digital output (e.g. pin 12) of the 44-pin Digital I/O port on the NI CVS-1459RT to high?
Is this possible without using the FPGA?

 

Thanks in advance.

Thomas

↧

PXI 7354

June 2, 2016, 6:05 am
$
0
0

Hi 

 

I am looking at the motion controller PXI-7354 in a PXIe-1062Q chassis with a PXIe-8108 Embedded Controller. After looking through the manuals and online sites for the PXI-7354 I have not been able to come to a clear conclusion of whether or not the motion controller could support operating an actuator as well as running a servo and/or stepper simultaneously. The manual states that the PXI-7354 has extra analog inputs running 16 bit, however I am unsure if those would suffice in what I am looking to do. 

 

Thanks 

↧
↧

Integrating 3rd party Varian x-ray detector to LabView

June 2, 2016, 6:39 am
$
0
0

I have a Varian Pacscan 4030x detector I would like to control with LabView 2015. I currently can extract images from a Neon BitFlow Frame Grabber card and display them. I am getting correct dark images using the frame grabber card. My next goal is to use the etherenet cable connecting the command processor of the detector to LabView to control detector modes, exposure time, frame rate, buffer time, ect. 

 

I have tried using the FPGA suite but in order to open the connection I need a bitfile. I do not know how to generate or find a bitfile for my detector. I also have the IMAQ suite. I am having trouble using IMAQ becuase I can not get my 3rd party detector to show up in the MAX software.

 

Thank you for your help! No vi's are attached because I have not been able to create any that are applicable to this problem.

↧

Continuous Generation in C - Speed issues

June 3, 2016, 3:28 am
$
0
0

I'm working with NI PCI-6561 using C language (VS2010). My task is to stream data continuously from memory (12 channels, ~16MHz). I've modified "ContinuousGeneration-StreamFromMemory" example for my needs. Everything works perfectly on my dev PC (SandyBridge, i7), but I have problems with my program to run on industrial PC (axiomtek fab101 PCI backplane, Ivy Bridge, i5). It works only if I reduce clock speed to 4Mhz. Even at 8Mhz I have buffer underrun errors. Any ideas how I can improve my program? NI docs tells about DMA mode, but I can't find an example how to use it using C.

↧

Measuring Two Line "Pulse" Width Using Digital Input Lines

June 6, 2016, 6:31 am
$
0
0

Hey all,

 

     I am trying to measure the time difference of two digital IO signals that annunciate the opened/closed state of a valve using digital lines.  Attached is my code and a couple pictures of what I have working so far.

 

I am left with:  

A) Measuring the time between when the first signal line goes high and when the second signal line goes low (time between CLOSED turning off and OPENED turning on and vice - versa).  

B) Alternatively, I can measure the time when signal OPEN gets asserted, and signal OPENED gets actuated (and vice - versa)

 

Below is code for all three loops.  Also below is the pseudo for what I am doing:

  1. I have the actuation working in labview, loop 1.  
  2. ???MEASURE TIME DIFFERENCE???
  3. And I have the annunciation of the two signals displayed on the Labview screen, loop 3.

I am using the USB-6525 and thus I only have one counter to work with and I WOULD LIKE to use the two digital input lines I am currently using  

  • the approximate time of open -> close is 2 to 10 seconds
  • The resolution needed is around 50ms
  • The signals are NOT periodic thus I cannot use the waveform measurement.
  • Open/Close actuation are both synchronous with respect to each other but the OPENED/CLOSED actuation are not. 

Let me know if you have any questions regarding my problem.  I feel like this should be a simple solution using the get_ms timer function and while loops to update the value until the signal changes (stopping the loop counter), but I don't know...

 

Sincerely,

Nicholas

CycleTest 1.PNG

CycleTest 2.PNG

↧
Viewing all 2182 articles
Browse latest View live
Search
<script src="https://jsc.adskeeper.com/r/s/rssing.com.1596347.js" async> </script>