I have a trouble reading signal from PXI-6251

When I want to capture data coming from a loadcell, it shows a graph which has maximum value of 10.5v and the real value is at the minimum. This happens frequently and the graph jumps from real value to 10.5v and then back again to real value. A sample screenshot is shown below, can anybody tell me what is the problem. Also it should be noted that DAQ and board have already been checked with another setup and they work very well so I'm pretty sure that the problem is on developer side!
Regards,

Are you performing any processing on your data? Are you performing a continuous or finite acquisition? Do you see this behavior in the Test Panel as well? How is your load cell wired? Typically load cells need external excitation. If this is the case for your load cell, what is providing the excitation? If this is a bridge-based sensor, then this document would be good to review. Hopefully this helps!
Regards,
h_baker
National Instruments
Applications Engineer
Digital Multimeter Resources

Similar Messages

Program to write signals from PXI 5105 using labview 2011

Hello
I am new in using labview. I need help in writing program to continuously record the signals form PXI 5105 using LabVIEW 2011. I prepared a program using help examples. It is recording the signal using pxi 5105 into the file after trigger. I tested the code using waveform generator with -100mV to 400mV, 1 kHz, sine wave. I have also attached the waveform of signal from the excel file recorded by the program. I have following queries
(i) Is the program correct to continuously record the triggered signals. Have I used the while loop correctly?
(ii) why some part in waveform is missing.
(iii) What should be the value of millisecond multiple ( I used zero)
I want to use above program for strain gauge signal measurement. Where I have to record the data at 20Ms/sec sample rate for 1 milli second after trigger.
thanks
Attachments:
Signal recording programme.vi ‏85 KB
recorded_signal.png ‏38 KB

Hi,
Sorry but I've only got LabVIEW 2010 so I can't open your file. If you can post a 2010 version I can take a look.
vinod_p wrote:
(iii) What should be the value of millisecond multiple ( I used zero)
If you are talking about the "Wait until Next ms Multiple" function then "Wiring a value of 0 to the milliseconds multiple input forces the current thread to yield control of the CPU." (from the context help for the function - press <ctrl>+h). Is this the behaviour you want?
Normally the ms multiple function is used to synchronise loops as it waits until the next multiple (be it 10ms or 10s) before continuing the loop.
-CC
"If anyone needs me, I'll be in the Angry Dome!"

Trouble reading data from GPIB instrument using VISA

Hello, I am having trouble with reading data from a GPIB instrument in LabVIEW. It appears that the data that is returned from VISA read is incorrect. (I used NI Spy to verify what it should be and what I get, they are different) The odd thing is that when I use the VISA interactive control utility to get the data, it works perfectly. Is there some sort of VISA property that I need to set to get it to work right? Writing to the device seems to work correctly. If you need more info, please e-mail me @ [email protected] Thanks in advance!

What exactly do you mean when you say the data you are getting is incorrect? I'm guessing that you are dealing with some sort of data type issue. The VISA Read VI will return a set number of bytes in string (ASCII) format. If you are expecting a different data type, you will have to do some conversion by either using a type cast or string conversion function. The type cast function can be found in the Advanced-> Data Manipulation palette, while the string conversion functions can be found in the String palette.

Route signal from pxi 6602 to RTSI

Hi,
I have a problem to export pulse from pxi 6602 to RTSI0. The code is simple as follows:
DAQmxCreateTask("",&taskHandle);
  DAQmxCreateAOVoltageChan(taskHandle,"AO/ao0","",-10.0,10.0,DAQmx_Val_Volts,NULL);
  DAQmxCreateAOVoltageChan(taskHandle,"AO/ao1","",-10.0,10.0,DAQmx_Val_Volts,NULL);
  DAQmxCfgSampClkTiming(taskHandle,NULL,1000.0,DAQmx_Val_Rising,DAQmx_Val_ContSamps,2);
  DAQmxCfgDigEdgeStartTrig (taskHandle, "RTSI0", DAQmx_Val_Rising );
  DAQmxWriteAnalogF64(taskHandle,2,0,10.0,DAQmx_Val_GroupByChannel,out,NULL,NULL);
  DAQmxCreateTask ("", &countHandle0);
  DAQmxCreateCOPulseChanTime(countHandle0,"TimingIO/ctr0","",
   DAQmx_Val_Seconds,DAQmx_Val_Low,1,0.5,1);
  err = DAQmxExportSignal (countHandle0, DAQmx_Val_StartTrigger, "RTSI0");
//  err = DAQmxConnectTerms ("TimingIO/Ctr0Gate", "RTSI0",DAQmx_Val_DoNotInvertPolarity );
  DAQmxStartTask(taskHandle);
  DAQmxStartTask (countHandle0);
the lines at DAQmxExportSignal(..) and DAQmxConnectTerms(..) both generate big negative number, I spent hours and no answer. In fact I have to use the counter to trigger other boards in my project, I plan to use the route signals a lot.
Sincerely,
Taishan

Hello Taishan,
Thanks for contacting National Instruments.
When you are using DAQmx with a PXI system, much of the signal routing can be handled implicitly by the driver. From your code, it appears that you want to use a counter output to start an analog output task. Please let me know if this assumption is incorrect.
When used while configuring your analog output task, the following function will cause the internal output of Counter0 to be routed automatically over the PXI backplane to the analog output device. I have assumed that your PXI-6602 is in slot 2 of the PXI chassis.
DAQmxCfgDigEdgeStartTrig (AnalogOutputTaskHandle, "/PXI1Slot2/Ctr0InternalOutput", DAQmx_Val_Rising);
The tutorials Getting Started with NI-DAQmx and Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications are great starting points for programming with the DAQmx API. Since you are using C, Using NI-DAQmx in Text Based Programming Environments, is a great starting point for comparing the LabVIEW API to the C API for DAQmx.
Please post back if you have any questions.
Regards,
Browning G
FlexRIO R&D

I have lost my reading list from safari.

I have lost all the items from my reading list in safari and it will not save any items, what can I do to retrieve the list? I get the message reading list is empty

Click the Reading List icon just left of the Bookmarks icon on the toolbar or Shift + Command + L
The Reading List can be hidden, but it cannot be removed entirely.

Analog signal from PXI

Hi everybody,
I have a problem: I cannot acquire 6 analog signals with a PXIe 8135 with 4MS/s. I use two boards with 4 MS/s, 16 bits and 8 Analog Inputs. I use a subVI of SAMPLE CLOCK for configuration with this parameters, Continuous SIGNAL, SAMPLE RATE = 4MS/s ( see attachment ). With one signal is ok, but with 2 signals, i have an overload Memory Message.
Where is the problem in the VI?
Thanks for your help.
Attachments:
acq_and_graph.zip ‏165 KB
acquire&loggdata.png ‏230 KB

Quickly looking through your code now, try removing the "Number of Samples analog". Since you are using Continuous Samples, you are just limiting the buffer and also limiting how many samples you can read at a time.
But you might want to think about using Finite Samples. You know how long you want to log for and you know your sample rate. So why not just do the simple math and tell DAQmx to get that many samples? You can use the DAQmx Task Done? VI to see if it is done. That would be much simpler than checking the time that has elapsed.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

Can't read signal from airport

I can connect my macbook directly to the ethernet and the internet works. My airport reads the internet when I plug the ethernet into it also (green light). But my computer won't connect to the internet via the airport. What gives?

ok correction - the AX is NOT successfully connecting to the ISP. There is a green light on the AX, but when I run a network diagnostic through Safari, it says I have an airport detection, but there is a yellow light for network settings, and red lights for everything else (including ISP failed). I tried to configure the AX using airport utilities, but it says that IP is already in use? Not only that, now the airport utility will not detect my AX so I can reconfigure it. Aaaaaaahhhhhh
Again, the situation: the ISP must work because I can get the internet directly from the ethernet to my mac. But the airport is not able to send the signal to my mac.

Trouble capturing waveform from PXI-4472

I'm really a very green newbie at this stuff, so bear with me...
I've got a PXI-4472 data acquisition board and a PXI-5411 waveform generator. I've connected the arbitrary out of the 5411 to the channel 0 in on the 4472. An external oscilloscope shows a 1v-amplitude sine wave being generated.
I created a very simple VI to show what the 4472 is capturing. It connects a NI-DAQ channel I generated to the standard "AI Acquire Waveform.vi", then out to a Waveform Chart, all within a while loop with a Stop button. Problem is, all the waveform chart seems to be showing is the running average of the waveform instead of the form itself (solid line, a tad above zero).
I can hook the 4472 input channel up to a DC-out power supply, a
nd when I vary the voltage, the waveform chart changes as well.
So my question (whew!): What's wrong here that's not allowing me to capture a waveform from the 4472 (in turn from the 5411) and display it on my waveform chart?
Thanks in advance for the help.

Never mind.... it was a sample rate problem. I upped the sample rate and it came out ok.

When using fire fox I have a problem reading pages from my site. This is a new problem. The format appears to be lost with fire fox but not IE

I have been using FF for several years and well as front page to maintain and upload to my site. As of two days ago I started getting comments that recently updated pages were not readible. I have not changed any settings but have found out that what can not be read in Fire fox can be read just fine in IE

Can you post a link to a public page that doesn't require authentication (log in) to access it?
Clear the cache and the cookies from sites that cause problems.
"Clear the Cache":
*Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now"
"Remove Cookies" from sites causing problems:
*Tools > Options > Privacy > Cookies: "Show Cookies"
See also:
*https://support.mozilla.org/kb/Websites+look+wrong
If you use extensions (Tools > Add-ons > Extensions) like Adblock Plus or NoScript or Flash Block that can block content then make sure that such extensions aren't blocking content.
*https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

How can i acquire analog signals from PXI 4472 card?

Regards
Aks
(Appreciate answers by giving KUDOS)
Hit the stars.............. sky is not the limit.

There are a lot of shipping examples for DAQmx. Once you open the example finder (Help>Find Examples), use the 'hardware' listbox at the bottom to find all of the examples that pertain to a 4472.
Message Edited by Dennis Knutson on 10-28-2008 07:30 AM

Read data from 3 arduino analog pins

Hi,
My name is Jack. I have a question about how to read multiply data from arduino analog inputs in labview. I have tried to read data from 2 pins by using same way (continuous analog samples) and the system works well. However, I failed in reading data from one more pin, no matter I used the same way as to read continuous analog samples or the method to read analog voltage.
My idea is to read battery voltage from pin 0, and the transducer voltages from pin 1 and pin 2 and convert them to currents. Pin 1 and Pin 2's signals work well, but pin 0 does not that good.
Another question is that how to plot data of pin 1 and pin 2 into one waveform chart. I have tried to bundle the two arrays; it didn't work, however.
Attached is my VI. Thanks for help.
Attachments:
final final project.vi ‏747 KB

This article presents a procedure for reading the analog ports of Arduino UNO R3 board , on which a Joystick shield was installed. The analog data are related to the position of command and can be monitored from the front panel of our program , for which we use serial communication.
https://decibel.ni.com/content/docs/DOC-33281
Atom
Certified LabVIEW Associate Developer
Attachments:
analog_JOYSTICK_ARDUINO.zip ‏1 KB
cmd arduino JOYSTICK.vi ‏65 KB

Transfer 20MHz signal from FPGA to RT

Hi all,
I am a newbie to Labview and FPGA programming... I am using NI PXIe-8133 Controller card and NI-5781 FlexRio card. My task is to take input of 20 MHz external signal and then process it further... I have to transfer that signal from FPGA to RT with the use of FIFO (that is what I understand). I referred the following example and succeeded in transferring a low frequency signal (range of KHz) from FPGA to RT as the sampling rate is in micro seconds.
http://www.ni.com/white-paper/11198/en
But I want to have sampling rate in nanoseconds if I want to take a signal of 20 MHz. How can I achieve that? Is there any alternate method apart from FIFO to achieve that task?
I am a starter in Labview, your help will be appreciated...
Thank you....

Hello Jimmie_A
Thank you very much for your help. The example really helped me to understand the input/out operation.
My application is to take a 20 MHz 'Phase Modulated' signal to FPGA and demodulate it. As a first step i want to take any arbitary signal of Mhz range and examine it if i am getting any phase noise or any other change in attributes.
I tried to give input signal to FPGA transferred it to RT and plotted it. Also from RT i sent the signal again on FPGA out pin to check on Oscilloscope and compare with the given input signal. Now my problem is I can see the signal on the RT signal plotter but I am not getting any signal back on FPGA pin. I have used Two different FIFOs for Target to Host and Host to Target communication.
It will be helpfull for me if you comment on my designed program for the said purpose. Here I have attached the screenshot of RT front panel. Also attached my FPGA and HOST vi files.
Thanks alot....
Attachments:
Host.jpg ‏141 KB
FPGA.vi ‏58 KB
Host.vi ‏400 KB

Reading files from 10000 sub directories

I have to recursively read files from 10000 subdirectories. Each subdirectory might have 1000+ files. What would be the best way to read directories recursively ? Is there anything better than calling listFiles and then checking if it's a directory. I am planning to read 1000 files during one cycle.

Your hierarchy structure is nothing but a tree.
For example take this strucutre:
A
B C
F G D E
Each node is a directory and the leaf node is file.
You can use Post Order Traversal. That is Left-Right-Root. You can select any traversal technique. All you have to do is check that each element you are currently handling is a leaf node or not.

How to get signal from analog input and send it to analog output (real-time)

Hi everyone,
I am doing simple task in Visual C++ and I am using PCI-6221(37 pin).
Basically, I want to send same signal from 'analog input' to 'analog output'
at the same time (almost), to make it real-time application.
Can someone please provide me sample program.
I would appreciate if you could provide me with the good tutorial which explains
step by step everything about programing NI-DAQmx for C/C++.
Best Regards,
Khassan
Solved!
Go to Solution.

This is my code in C++, you can optimize it if it looks too messy. This code reads signal from analog input and outputs it through analog output.
To make this code work additional include directories and library directories must be added from NI.
I hope it helps someone.
#include <stdio.h>
#include <conio.h>
#include "NIDAQmx.h"
#include <math.h>
#define DAQmxErrChk(functionCall) { if( DAQmxFailed(error=(functionCall)) ) { goto Error; } }
int main(int argc, char *argv[])
int32 error=0;
TaskHandle taskHandleRead=0,taskHandleWrite=0;
int32 read=0;
float64 dataRead[1000];
char errBuffRead[2048]={'\0'};
char errBuffWrite[2048]={'\0'};
bool32 done=0;
int32 written;
DAQmxErrChk (DAQmxCreateTask("",&taskHandleRead));
DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandleRead,"Dev1/ai0","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,NULL));
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandleRead,"",100.0,DAQmx_Val_Rising,DAQmx_Val_ContSamps,0));
DAQmxErrChk (DAQmxCreateTask("",&taskHandleWrite));
DAQmxErrChk (DAQmxCreateAOVoltageChan(taskHandleWrite,"Dev1/ao0","",-10.0,10.0,DAQmx_Val_Volts,NULL));
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandleWrite,"ai/SampleClock",100.0,DAQmx_Val_Rising,DAQmx_Val_ContSamps,1000));
DAQmxErrChk (DAQmxStartTask(taskHandleRead));
DAQmxErrChk (DAQmxStartTask(taskHandleWrite));
while( !done && !_kbhit() )
DAQmxErrChk (DAQmxReadAnalogF64(taskHandleRead,1,10,DAQmx_Val_GroupByScanNumber,dataRead,1000,&read,NULL));
DAQmxErrChk (DAQmxWriteAnalogF64(taskHandleWrite,read,0,10.0,DAQmx_Val_GroupByChannel,dataRead,&written,NULL));
_getch();
Error:
if( DAQmxFailed(error) )
DAQmxGetExtendedErrorInfo(errBuffRead,2048);
DAQmxGetExtendedErrorInfo(errBuffWrite,2048);
if( taskHandleRead!=0 )
DAQmxStopTask(taskHandleRead);
DAQmxClearTask(taskHandleRead);
if( taskHandleWrite!=0 )
DAQmxStopTask(taskHandleWrite);
DAQmxClearTask(taskHandleWrite);
if( DAQmxFailed(error) ){
printf("DAQmx Error: %s\n",errBuffRead);
printf("DAQmx Error: %s\n",errBuffWrite);
printf("End of program, press Enter key to quit\n");
getchar();
return 0;

How to Read data from Infocube

Dear Friends,
I have requirement to read data from Infocube.
I know the Function module(FM) which SAP provided. The FM name is RSDRI_INFOPROV_READ.
But when i am trying to execute this FM in SE37, it giving "Error generating the test frame" message.
I called this FM in start routine, it giving error while loading.
If any using this please let me know, how to use this. If any have sample code, please share.
Thx
Raj

Hi,
i used to check documentation all time, but this time I forgot to check.
It is well documented. thx for igniting my mind.
bye
Raj

I have a trouble reading signal from PXI-6251

Similar Messages

Maybe you are looking for