Simultaneous measurement

Similar Questions

• Triggering and simultaneous measures

  Hello world

  I wrote a Vi to acquire data simultaneously from 7 devices. I use cDAQ9178 with NI9203. The vi will acquire current values 4 to 20mA. Could you please check the attached file and let me know if I need to improve.

  I have a question and I would be grateful if someone can help me to answer.

  1. how to open the binary file for writing to the file measured by EXCEL?

  2 is it better to use write on the worksheet for data recording, if yes how to include the time column?

  3. I will use external trigger via the port of PIF0 signal, is it OK to do with dag support? I have not yet tried, but it seems simple?

  4. Finally, I have another vi for the valve which should be triggered with vi as, is their anyway to do it? I was thinking of the authors of the notification, but I don't know how to use ?

  Sorry to ask too I really urgently need all this. I should finish my Tuesday data acquisition system

  Best regards

  In your example above, you have the Setup to write it into a file measure so it renames an existing file. This replaces the file at each iteration. You must change this to add to the file. It's in the "If this file exists' section of the configuration dialog box.

• In the control loop time interval and simultaneous measurement

  Hello world

  I just started to learn labview so please do not judge my messy programming

  I want to constantly measure certain values (humidity, temperature, etc.) and once a certain threshold is crossed, I want to activate a device. Measure and activating things works perfectly if used separately. If I combine it and measure for awhile (10 samples at 100 Hz continuous playback mode) I get the error 200279 "attempted to read samples that are no longer available.

  If I use (100 samples to read 100 Hz n samples) it measures for some time (interrupted manually after 4 hours), but I recognized that there was a gap of time of half an hour between the timem system and the 'real' time shown in the table.

  Oh, and this isn't really critical time. It is enough if it measures one sample per 5 seconds or more.

  Is there a quick fix and dirty for this?

  Thank you for your very long in advance.

  Hendrik

  
  

• Trigger digital beginning for simultaneous tasks of HAVE and AO

  I am trying to create a Subvi to simultaneously measure 5 signals of HAVE and an AO output signal.  The AO signal feeds a diet that feeds in turn my sample.  It HAVE the applied voltage, current temperature measurement (via a shunt resistance), via a V 1-5 of a pyrometer optical signal and two other sensor input voltages.  During the test, I would also like to vary the applied voltage, so I set up a ripple of tension values.  To make things pretty simple I execute the tasks of HAVE it and AO at the same pace, and I want the two tasks to start at the same time.  To reach the start of the trigger, I wired an additional set of contacts on the power relay to line 0 on a DIO 9401 resident module in slot 5 9172 chassis (access to the PFIO signal).

  Attachment is the base Subvi, I came with to do so.  I think it is the task of the AI seems to trigger correctly, but the AO seems to start as much as 100 msec before the start of the task to HAVE it (sometimes it is dead on, but other times not).

  Will I put in place these tasks to start at the same time, or is my approach to programming off?

  Here's my hardware configuration

  1. If you want to start both tasks at the same time and run synchronously, you don't need two digital triggers start. Take a look at the example of Multi-Func-Synch AI - AO.vi in the Finder of the example.

  2. Design your architecture using the State machinery rather than using the Structures of the sequence. Take a look at a model of State machine in the file-> New...

• Unique finished and differentiated steps of simultaneous action on a USB-6009 device?

  
  

  Sorry, I set off on the "Simultaineous" - the 6009 does not support simultaneous measurement.  Yes a task with multiple channels can have mixtures of complete and differential channels in a scan string-, but they must be on different inputs.

  for example, AI0 diff and SE AI1 is ok

  AI0 diff and AI4 SE is not as AI4 is reserved for the AI0 negative input.

• PCI 5154 sampling rate

  Hello

  What is the sample rate max 5154 PCI for two channel inputs? The manual States the 2GS/s is for one channel only. So, am I not able to get a bandwidth of 1 GHz for the simultaneous measurement of two channels? Thank you!

  Hi gbhaha,

  First of all, TIS mode up to 20 GECH. / s using an ADC, while your real time sampling uses two converters a/n at the same time to a single channel.  Take a look at these diagrams that I linked in my first post for more details on this architects.

  About the difference in the bandwidth between the 5153 and 5154 - the 5153 has 500 MHz of bandwidth in its circuits, even when acquiring at faster sampling rates.  The 5154 1 GHz of bandwidth, this is why it is more expensive.

  Kind regards

• Acceleration in the frequency domain

  Hello

  I enclose a vi that I already modified the existing example. I will use this vi to measure pressures (pressure sensor) and acceleration (from an IEPE accelerometer). Each of the two sensors is connected to a housed in a chassis CompactDAQ C Series module connector 4. The pressure sensor measures the pressure of the water flowing in a pipe while the accelerometer will simultaneously measure the vibration of this pipeline caused by the fluctuation of water pressure. In this vi, I am connecting a signal of pressure and acceleration TDMS file and then read the two signals on the cards of distinct waveform. The acceleration signal is written and read in the time domain. I need your help to make change more on this vi to take the acceleration signal and read on a separate table in the field frequency and written also the frequency of the field values in a file of PDM. After this change, the vi is supposed to have three graphics of waveform (pressure, acceleration time-domain and acceleration in the frequency domain and opens two tdms files, one for pressure and acceleration in the time domain and one for acceleration in frequency domain.)

  I tried many ways all failed because I'm not very familiar with the measurements of vibrations.

  I thank in advance.

  Hello

  It is important that you should decide if the frequency data you are interested in are constants based on time, or if you need to know how the data of frequency changes over time.

  For constant frequency over time, take a look at the Fast Fourier Transform: http://www.ni.com/white-paper/4541/en/

  If you need to know how the frequency display, take a look at the analysis of the frequency of the common time: http://www.ni.com/white-paper/3548/en/

• slow and timeout error

  Hello forum members

  I wrote a program in LV2010 and works very well except for one last question.

  The program works very slowly and sometimes shows error timeout. In the program, I send a voltage to Keithley 2400 and simultaneously measure the current Keithley 2400 and 2000. I sweep the voltage using a while loop. I have not used buffer.

  Your help would be very appreciated.

  Thank you.

  Pradeep

  A few things I noticed:

  1. You should not mix GPIB and VISA to speak to the same instrument.  You should just use the entry VISA to send your order.  But if there is a VI later in driver for the 2400 set the voltage from the source, you should use that.
  2. If you insist on the construction of your own SCPI command to set the voltage of the source, make sure that the command structure is correct.  You may need to add a semicolon or an end of line at the end of the command character.  That's what I suspect causes the header not defined error.
  3. Really, you should add a delay between voltage and then perform readings.
  4. I don't like the idea of allowing the two different screws communicates on the same bus at the same time.  I've seen some strange things with GPIB.  You should sequence a little more so that you adjust the tension, wait 500ms (round number to allow things to sort out and the bus to talk to nice), read the voltage of the 2400, read the current 2000.
  5. Your back measures seem to me.  I usually use the 2400 (source meter) at a voltage of the source and read the current, then read the voltage to the unit under test with the 2000 (DMM).

• How to find the time between two channels of entry in the data acquisition card or pci 6036

  Hello

  I read a lot-related posts on the simultaneous measurement of two input voltage of similar channels in map data acquisition. I know that the best material is "simultaneous measurments of the Series DAQ cards" but I only pci data acquisition card 6036 and I try to understand what is the time between the reading of the two channels . This period is always constant? (must it rely on a voltage (amplitude, frequency, waveform..). I send the sine wave (s) to the two channels and read the values of V, if they read the same value, the difference should always be zero but I get-0,002 to 0.002 Volt difference (I must find a way to convert it in time). A screenshot of my VI is attached. I wonder how I can accurately measure the time delay between the channel.

  I am open to any suggestion, my final goal to read exactly two channels at the same time ((ou connaître le délai exact donc je peux correspondre les données correspondantes étant donné le temps de retard))

  Hi spinup,

  better you should post your question in the forum of LabVIEW, LabWindows/CVI is used

  Good luck.

• divided time base

  In the simultaneous measurement with AI and AO, I used SMU-6124, that supports the time base of 80 MHz clock.

  I was told that I can use 80 M/n (integer) as a sampling in SMU-6124.

  In order to obtain n is integer, I limited my settings for 2 to 5 common factors.

  But, why the actual sampling frequency is different from the sampling frequency of entry, 1.6 MHz (n = 50).

  Real rates are 1.67E + 6 (analog input) and 1.54E + 6 (analog output).

  What is the problem for this problem?

  Any other consideration in its sampling frequency?

  labmaster.

  Hi labmaster,.

  Looks like you're on track - to answer your questions:

  0) meter tasks can use the time base of 80 MHz (20 MHz and 100 kHz are also available).  So the frequencies available, you can generate using the meter is 80 MHz/N, where N is an integer (between 4 and 2 ^ 32).  You are still limited to the average fracture, but you would work with a higher time base so you could reach the frequencies that you couldn't otherwise (for example 1.6 MHz).

  (1) you can check the actual sampling frequency of the counter by using the following property node:

  

  (2) you can run GOT it, AO and two counters at the same time in separate tasks - I'd start, AO and Ctr2 before Ctr1 so that all tasks starts at the same time.  If you started Ctr1 first, then the clock will then perform tasks would begin at different times (software-based) unless you use a trigger to start.

  I'm glad to hear that this has been helpful to you, I hope all is well and good luck to you with your application!

  -John

• problem scanning with keithley 2420

  Hello

  I'm having some trouble to configure the Keithley 2420 to sweep a range of Volt and measure the amps in a cell.

  The vi attached check the polarity of the voltage, then measure the short circuit current and then performs a scan.

  The program runs, but scanning seems to measure resistance and outdated.

  Any help would be greatly appreciated!

  Incase anyone reads this, the problem was with the drivers Keithley 2400 do not turn off simultaneous measurement mode when you set up the type of measure. Even if I set the type of measure amps, he was still measuring ohms.

  I still don't know why it uses default ohms.

  Anyway, I solved this problem by using the ENS:FUNC:CONC OFF command with the Instrument i/o assistant after having used the driver concerned of Keithley VI to set all other settings.

• measure with the two channels of the virtual bench simultaneously in labview, error 375903

  Hi, I am trying two measurements simultaneously using two channels of analog input of the virtual bench. I chose the channel MSO 1 and 2 for the measures but I get error 375903 returned evewry time say the requested resource is reserved. I'm not under any other software which should use the virtual bench. The error occurs when I'm initializing the session, even before a measurement was made. Can someone tell me how to call each channel so that I don't get this conflict of resource reservation?

  I have included the VI and a screenshot of the error.

  Thank you!

  NGKai wrote:

  Hi, I am trying two measurements simultaneously using two channels of analog input of the virtual bench. I chose the channel MSO 1 and 2 for the measures but I get error 375903 returned evewry time say the requested resource is reserved. I'm not under any other software which should use the virtual bench. The error occurs when I'm initializing the session, even before a measurement was made. Can someone tell me how to call each channel so that I don't get this conflict of resource reservation?

  ASM takes only supported a session unique instrument and your VI uses two. To use both channels, delete the second session MSO and specify channels in the MSO configure Analog Channel.vi

  Here's an example that uses two channels brought:

  VirtualBench: Bode Analyzer with the FGEN and MSO

  http://www.NI.com/example/52076/en/

• 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!

  
  

• The measure of multi-lane thermocouple simultaneously via 9213 (with USB 9171)

  I'm just back in Labview after 10-year absence.  My first goal is to measure thermocouples of Type J and T with a 9213.  A 9213, 16 channels, but the screw example I found so far allow only a channel be selected at a time.  Ideally, it would be good to have the option to select among the 16 tracks to read at some point (that is, any combination of 1 to 16 and channels jump if necessary).

  Secondly, multiple channels for simultaneous playback selection will affect the sampling frequency?  For example, if 10 samples can be read per second, and selects 16 channels, does it take 1.6 seconds for all read?  And what happens if I put the sampling rate of 1 second in the previous example?  It keep track of cycles "planned" and keep running unfinished loops after that I have to stop?

  Thirdly, I don't understand whether it is possible to assign a different thermocouple for each channel type.  Can I combine thermocouples of Type J and T on the same card?  Is the case, then how to set each channel individually?

  Fourth, I met error readings when you select a channel open to the VI for the 9213.  Is this normal?  Ideally I would like to be able to Exchange thermocouples during continous measurement and worry that the program will crash.

  Example of two screws, I found are: "Input.vi Thermocouple - continuous" from the Finder of example of OR.  The other is spent by the sample project "continuous measurement and logging (OR-DAQmx)."

  
  

• simultaneous acquisition of the accelerometer and a measure of a rotating machine encoder.

  I want to make a simultaneous purchase of the accelerometer and a measure of a rotating machine encoder.

  So what National Instruments data acquisition product must be chosen to do this capture.

  Sure that if your accelerometers do not need power IEPE (maybe you have an external power supply for the accelerometers) and if the voltage sensor is located in the voltage of the sensor of the 6221 range.