The PXI - 6259 sampling rate M SERIES DAQ

Similar Questions

• Check an ADC with the PXI-6259

  I use the PXI-6259 M Series DAQ in LabWindows/CVI ADE, and now I want to check if a 8-bit ADC works properly or not.

  The entrance to the ADC is a sine wave and I acquire the 8 bits of data (in Digital Format or Port) every time that the A/D conversion is complete. Then, I want to regenerate the sinusoidal wave with digital data using 6259.

  The analog channel supports only the numbers to decimal floating 64-bit data format but not Unsigned and data format signed integers, have of I scale digital data acquired for floating-point numbers 64-bit data format according to the amplitude of the sine wave and then regenerate the waveform?

  If so, I have to Brown the APFI0 or the APFI1 as the DAC reference voltage source?

  Thank you very much for your help.

  Sxs707

  Done writing DAQmx supports the signed and unsigned writings. Open the library > NOR-DAQmx > write functions and find DAQmxWriteBinaryI16, DAQmxWriteBinaryU16, etc.

• The PXI-8512 does support the series 2 filter or a similar mechanism to filter the messages?

  Hello

  I need to buy a couple of cards CAN interfaces for my test application and I wonder what you choose

  I already used a PXI-8461 to obtain data of the customer model under test, and due to the fact that sometimes the client bus can be very busy, but most of the messages is not interesting for my system that I use currently series 2 comparator/mask/filter to filter only the interesting messages.

  Without this filter, the PXI-8461 often returns an error due to overloading of the bus. With the filter, everything works perfectly

  Now I need to implement several testbeds with this same feature, and I plan to move to the new PXI-8512 for new.

  My question is: is the most recent PXI-8512 a device series 2 institutions? Support the filter 2 series or any other mechanism to avoid problems on the busy bus?

  Thank you for your support.

  Kind regards

  Davide

  Hi Davide.

  the PXI-8512 isn't a series 2 device. The PXI-8512 is a device of the X-NET family. X-NET is the technology whose use OR in support of CAN, LIN and FlexRay with a driver API. Series 2 devices use the former NI-CAN driver that only supports the CAN. All of the new devices are devices X-NET.

  Take a look to the following document:

  NI-CAN for NOR-XNET application migration
  http://www.NI.com/white-paper/9717/en

  On this page you will find the following statement for the function that you are already using:

  Transceiver filters were traditionally indicated for applications where only a few CAN IDs have been considered on a bus high load. In some cases, material NI-CAN support the bandwidth of the full bus, which leads to a buffer overflow. The hardware architecture OR XNET uses the engine NOR-XNET DMA-driven to eliminate the occurrence of buffer overflows. CAN of NOR-XNET interfaces are able to handle high load bus and transmitting at the maximum rate without coupling to buffer overrun. If your applications use the hardware filters extensively, NOR recommend setting up CAN opposes, or by reading the bus while using Network Interface objects. The best option for these applications is to modify your code to use the API OR-XNET native.

  Best regards, Stephan

• On the NI PCI-6221 fast sampling rate question

  Hi I was wondering if someone can answer a question of sampling rate on this card to PCI-6221 (http://sine.ni.com/nips/cds/view/p/lang/en/nid/14132).

  Especially if I wanted to transmit simultaneously (analog output) and data acquisition (analog input), what is the sample rate max I could use. Kind regards.

  Since the 6221 is multiplexing the analog input, your question for I / simultaneous ao is possible for one channel of the only. If your "simlutaneously" can include delays (e.g., 100us), you may be able to work with several AI channels as well...

  HAVE the multiplexes, workable sample rate given that the total sample (250 kHz) frequency divided by the number of channels that you use. AO is faster than HAVE it, so it does not reduce this number.

  hope this helps,

  Norbert

• With the NI 9205 module Max sampling rate - problems

  Dear friends,

  I develop a project of lv, which makes and control system of engine dyno. The material is CRio-9022 with other cards and also 9205 for AI. There is an encoder for angle attached to the motor shaft with 3600 chatted by Tower as well as an index to indicate the end of a revolution. the output of the encoder is measured by card 9411. The speed of the motor is 1500 rpm. I measure pressure data and couple when I receive a 'tick' of the wheel. This means my sampling rate for pressure and torque each is 90KO/s.

  but I was not successful to lead it. The program is great and I can show them, but I believe that there is a problem in the choice of material for the task. With the data of pressure and torque of the 9205, I also measure other channels for the controller output mass flow and temperatures. So in all I use 8 channels of the 32 available. But only the pressure and torque are acquired at the wheel-driven sampling rate. the rest are acquired about 5 times per second.

  Since the 9025 is a multiplexing ADC, 250K sampling frequency is divided by the number of channels accessed = 250 K/8 = 31 K samples/channel. With this in mind, I decided to acquire data of pressure and torque with each beat 3rd rotary encoder, essentially on 30K samples/s sampling. However, I see a large amount of noise.

  So I decide to average more than 1 second cycles (so the engine runs at about 25 cycles/sec, I averaged over this issue). The resulting pressure and torque graphics do not match with those measured by an oscilloscope in terms of amplitude but the frequency and shape is correct.

  I noticed an interesting feature in the charts. When I pass interpolation between the points, I see several curves made by points instead of a continuous locus of points. Accordingly, I find that the acquisition is slower than necessary, and so there are less number of points sampled as required. These points are not synchronized 25 cycles I have on average and therefore the separate "curves". It is because of the possibility that some points receive a higher number of 'contributions' several times (when you add), the neighbouring points.

  so I conculde that the 9205 is not fast enough to do the job. also noise, perhaps due to crosstalk or gosting when the mux changes channels. the impdences output pressure and the couple are of the order of 10 K ohms.

  the Labview code outline: well, there is a vi FPGA, which takes the rotary encoder ticks and sends a signal to the case of each 3rd tick. The signal contains a 16-bit integer, indicating the number of ticks. This signal is sent to a 1 element FIFO. This fifo is read in a parallel while loop, where it remains awaiting a new element. The while loop bed fifo, where data are available, takes a measure of pressure channel. A node memory of the method is called to provide data according to contained in the index number equal to the number of ticks to signal fifo. Then he adds the current pressure reading to the reading of the memory and stores the sum in the same memory location.  Thus, an array of elements of 1200 is formed, where each elemnt is a sum of the values taken of more than 25 cycles. This memory is transferd to a dma fifo and reading side host. is done similarly to involved couple. host-side the fifo is read and divided by 25 to get the average. This average is displayed on a waveform graph.

  Please check the attached file to get an idea of the problem. Sorry for the long post.

  Please suggest if you understand the problem and suggesstions or solutions.

  
  

• Hardware timing on PXI-6259

  I'm having a problem of selection of a clock for the PXI-6259. I've seen several posts on the forum on this issue, but the solution seems to be "read the manual"; I am not able to total, try it.

  I have a chassis with an analogue 6723 static on the map and a 6259 multifunction data acquisition. I provide 4 sets of 2 digital inputs: a guideline and a pulse line. The user selects a number of impulses, a pulse width, and a destination for the pulse train. I use the number of pulses and pulse width to set up a digital waveform clocked. I can write the direction static c on the 6723 and the train of pulses at the timed HW DO on the 6259.

  My problem is to select a clock for the pulse train. I tried using the sample AO clock and the sample clock HAVE to give me the ability to adjust the pulsewidth. I add the additional sample for the "wait until what Done.vi", but it times out when one of these clocks are used. If I use the time base of 100 kHz, the vi works well - but only for a 10us impulse. With the help of the time base destroyed my ability to change the pulse width.

  I have attached the screw below; He let me just tie three.

  The vi parent - control Tach, Full.vi

  The creation of impulse vi tasks - create Pulse Channels.vi

  The output vi - generate Tach Pulse.vi

  The RWA selector is a typedef that selects one of the four outputs to send the train direction of signal and pulse to.

  The typedef of Direction is converted to a Boolean value to write to the direction of entry.

  I first create an array of tasks for the static DO the map of 6723, a special track.

  Then, I create an array of tasks for the pulse on the map of 6259, including the establishment of the clock. I do this by taking the desired number of pulses, doubling (each pulse takes two samples), then adding one to allow the impulse to settle. I also add another sample, in addition to that for the vi "wait until what". This is the vi where to select which one to use.

  I then choose the task of a pulse and direction, enter the values in the buffer and start explicitly jobs. After that wait until done return, I stop the tasks.

  Waiting until it times out (I used up to 10 s) am the AO or sample clock is used. If I remove the wait until done, I get a warning (task may have stopped before all the written samples) with no output pulse train. It works very well with a time base of 100 kHz, but of course its fixed and cannot make any other sample rate other than 100 kHz/10us.

  I have three questions:

  1. the main problem - what I'm doing wrong with the clocks?

  2. I put the program in time loop to allow the sending of one of the 4 outputs. I can send reverse or forward impulses out even any number of times, but the VI produces an error if I try to switch to another output (turned off, so I don't have the exact error code; it tells me that the task is reserved).

  3. is it necessary to replace the task in the table when I'm done with it (for example, replace the code table subset)? What is exactly included in the thread of the task?

  Had some extended time for testing today, and I found a solution. It is much more complicated as the example shows, although it seems obvious, once I write it.

  It takes two tasks and two knots of timing to accomplish the digital generation timed by material:

  A single task and node of synchronization for the digital task, I had put in place already

  A single task and calendar for an analog task node allow the sample clock. I needed an analog task with a channel not used AND a timing node. Analog synchronization node should have the same sample rate and the number of samples that the node digital synchronization, but the source entry should be left blank to use the default clock (sample clock HAVE for a fictitious analog input channel).

  Sailing smooth after that. Thanks for the help and insight!

  -Nick

• The PXI-4461 connections and text based programming

  Hello

  I looking for a guide-schedule based on text for the PCI card, / AO PXI-4461 24 bit.  Currently, I am able to program it similar to the PXI-6259 but could not find a way to set it up as (differential, Pseudo-differentiel) in order to obtain the correct output impedance.

  Is there a hardware (user) for PXI-4461 guide?

  I use Visual c# to encode the PXI-4461.  How can I determine the location of the classes and the specific methods for the PXI-4461.

  Thank you.

  Anand

  
  

• Units of the number of samples and rates for the DAQ Assistant units

  Hello

  I use the DAQ assistant for analog voltage of an input OR data acquisition card. What is the difference between the rate and the number of samples in the DAQ assistant and what are the units of the two?

  Thank you.

  The number of samples is how many discrete to measures. Rate (per second) is how fast to acquire the specified number of samples.

  If number of samples is 100 and the rate is 1000 samples per second, then the acquisition would take 0.1 second (100 / 1000).

  -AK2DM

• If I use a few channels on PCI-6259 to increase the sampling rate, channels numbers can I be contiguous?

  We are looking to buy a card PCI-6259 usable on a Linux machine. We would use NIDAQmx to access the card. If we were to use only a few channels to increase the sampling rate, do I need to select specific channels?

  For example, the card is 1 MHz. If I select the channel 1 and channel 2, I can taste each channel at 500 KHz. could I choose 8 channel and channel 13 and still be able to sample each channel to 500KHz? Or need of specific channels to use when a subset of channels are selected?

  Thank you

  -Tom

  Thanks for the quick response.

  -Tom

• Sampling rate higher for the measurement of precision meter

  I have a BNC 6259 M Series DAQ USB. I am currently using the DAQ Assistant to perform simple cash rising measured with the measuring mode single sample on request. I tested my VI with a known square wave with a function generator signal and it clearly lacks a few edges. I think that the solution lies in faster sampling. However, I was not able to understand how to use clocks to set up continuous sampling mode. I tried the forums and I found articles that were close, but not quite exactly the problem I am facing with as (http://forums.ni.com/t5/Digital-I-O/trying-to-use-NI-6251-s-DIO-port-as-input-and-output/m-p/448035#...) or (http://forums.ni.com/t5/Multifunction-DAQ/Using-Counter-of-PCI-6024E-with-Quadrature-Encoder/m-p/984...). Any guidance here would be great.

  In fact, the calendar should not have anything to do with the edges being detected.  Configuration of a sample clock for a county of just edge task allows you to enjoy deterministically in the account register and has no impact on the edges which can be counted.  Also, the analog examples really have nothing to do with what you seem to be asking questions on.

  ... So it leaves the question unanswered as to why you might miss the edges.  Perhaps the following information could shed some light on the question:

  1. it is possible that you do not configure the counter exactly as you think you are.  Can you post the VI you use?  As a point of reference, count digital events shipping example does not use any clock sample timing and just questioned the value of the register count with a software loop, but the meter should not miss all this edge on the input source.  There are examples that are timed by the material available as well, but this is not necessary, unless you need a constant specified dt between your counter samples.  To use the examples of the timed sample, you will need to generate a clock of either another subsystem on the map or use an external clock.

  2. assuming that the configuration of the counter is not the issue, there may be a problem with the method that you use to determine if you are away from the edges.  How do you know that you are away from the edges?  The function generator produces only a finite pulse amount?  You start the meter before start out impulses?

  3. If the two points above do not raise red flags, it seems likely that the meter is registered just not some of the impulses of your FGEN.  Can I assume that the output of the FGEN is 0 - 5V TTL?  What is its frequency and duty cycle?  The maximum external source for the meter on the M-series products: DAQ (like the 6259) is specced at 20 MHz, but this depends on a clean signal with good connections.  At frequencies above it, the bandwidth of the front-end of the PFI lines becomes limiting.  If you have an available specification document for your FGEN I'd like to be able to see it.

  I hope this gets you throw on the right track to solve the problem - impatience comes back with more information.

  Best regards

• Why my sample rate does not match the output of timestamps in the waveform?

  Hello

  I run a simple application to read the data of two pressure sensors output signals 0 - 5V to a NI9215 module, and one connected to the 9237 module load cell. They are housed in the 9172 chassis.

  I am new to DAQ and labview, and I find it difficult to reconcile the sampling frequency that I put in the sample clock and the apparent rate data (according to the timestamps in the waveform that I output to a text file). For example, if I ask 100 Hz rate (and 10 samples to read), the data appear to sample at 1612,9 Hz. If I ask the sampling frequency of 1000 Hz, outgoing data is 1612,9 Hz to 20 kHz, the data came out to 25 kHz.

  Can someone tell me to trust the timestamps given in the waveform that is written in the text file, and if there is a way to check this?  If this timestamp is correct, how can I force the application of sample data at the requested speed?

  As a secondary issue, in my attached VI, you can see that I have an attached to an array of construction shift register. I can't understand how to initialize the array outside of the loop as it clears the table before the next time I run the program. Any advice?

  My VI is attached.

  Thank you

  Claire.

  Hi Marc, thanks for the quick response and the right explanation. It's all much more clear now.

  Have a great weekend,

  Claire.

• RF Mux PXI-2546 driver stops working when DAQ SMU-6259 is used.

  Hi, I am experiencing a very strange thing. I have a system with two 1065 equipped chassis with about 15 different instruments.

  It was working fine and has done for several years. Today the SMU-6363 DAQ crashed, I tried to replace it with a spare DAQ SMU-6259. I started with switching just the daq spare in but then the computer crashed every time during the installation of the pilot SMU-6259. So I thought that I need a driver update and installed DAQmx 15.1 (previous version was 14.5). It has not made any change. Computer always crashes constantly. Finally I found that if I remove the PXI - 2546 Rfmux in the SMU-6259 DAQ system will install and work properly. But now Rfmux PXI-2546 will not work when acquiring data SMU-6259 are installed on the system. I can get the Rfmux to work if I take the DAQ and vice versa.

  Why is it like this and what can I do to solve?

  I do not understand why a PXI-2546 Rfmux and an SMU-6259 DAQ interfere with one another.

  / Erik

  Hi Anton, thanks for your answer!

  Yes, it's very strange. I narrowed down it to these two devices. I got the blue screen during the installation of the Windows driver. So I tried first update the driver OR DAQmx. Who did not have any change.

  Then I tried to roll back the NOR-DAQmx driver to a previous version. Crashes stopped then, but I could not both devices to work simultaneously. In the windows Device Manager, he showed a problem for the NI DAQ PXI-2546 peripheral device. I don't know why a mux is considered DAQ hardware either. The description of the problem says "some free resources". If I could get the Rf mux to work if I unplugged the daq and vice versa.

  For the last two days, I was reinstall the system from scratch. I'm not done yet because it takes so much time to do this, but it seems to be ok now. But what a pain. I started with just the driver Rf Mux (Switch).

  To do this I had to download almost 3 GB! For a 2 x 4 x 1 Mux driver. Then, the driver for the installed switch some NOR-DAQmx which I had to then update and download even more.

  I think that NEITHER makes it very complicated with the pilot stuff. Instead of having these huge drivers packages which supposed to cover everything, it would be better with the smaller specific device drivers that could be easily found on the web under each device.

  In any case I hope it should work ok now. I wonder what will happen when I get home my repaired SMU-6363. Should I plug it in or simply do not bother because I could face the same problem again?

  / Erik

• How to increase the sampling rate in this VI?

  Hi all

  I have recently inherited this mess of a VI and can not figure out how to increase the sampling rate. I tried to change the "ms of waiting ' clock, but it does not add more data points." The main VI, as well as the Subvi, which contains a Daq Assistant to a load cell and LVDT is attached. Any ideas on how to improve the sampling without a complete overhaul would be greatly appreciated!

  Thanks in advance!

  If you are grateful, feel free to give congratulations and mark the topic as resolved.

• Save the high sampling rate data

  Hello!

  I use NI PXI-4462. (204.8kS, input analog 4 / s sampling frequency)

  I want to collect data from "load" (channel 1) and "acceleration sensor" (2nd, 3rd, 4th channel).

  I also want to save data to a text file.

  So I do a front pannel and block diagram. You can see in the attached file.

  The program works well in a low sampling rate.

  However, when I put up to 204800 s/s sample rate, the program gives me "error-200279".»

  I don't know what means this error, and I know why this happened in the high sampling rate.

  I want to know how I can fix it.

  Is there any problem in my diagram?

  Is it possible to save high sampling rate data?

  I really want to samplling more than 200000 s/s rate.

  I would appreciate if you can help me.

  Thank you.

  NH,

  You have provided excellent documentation.  So what has happened is that the amount of time it takes to run the other portion of the loop results in a number of samples to be taken is greater than the size of the buffer you provided (I don't know exactly what it is, but it will happen at high frequencies of sampling high) resulting in samples are crushed.  You might be best served in this case to take a loop of producer-consumer - have the loop you have acquire the data but then have an additional loop that processes the data in parallel with the acquisition. The data would be shipped from the producer to the consumer via a queue.  However, a caveat is that, if you have a queue that is infinitely deep and you start to fall behind, you will find at the sampling frequency, you specify that you will begin to use more and more memory.  In this case, you will need to find a way to optimise your calculations or allow acquisition with loss.

  I hope this helps.  Matt

• Question DAQ sample rate

  Hello

  I tried to understand how the 'number of samples' and 'rate' controls affect the frequency of sampling for the DAQ hardware. For example, say I want to acquire data from a sensor of pressure at a frequency of 10 Hz intuitively, I would think everything I do is on the desired sampling frequency, in this case 10 Hz control the 'frequency', try this, I know that's not true. I read that 'number of samples' affects the sample rate by setting a buffer value that must be reached before the VI will process the acquired data. So I also tried to set the "number of samples" to 1 and "rate" at 10, thinking this would have led to a sampling frequency of 10 Hz, and again, it is not. The only way I know to control the sampling frequency is using the wait function (ms), but then I always get buffer overflow errors.

  Can somone if you please explain to me the error in my thought process and also tell me the best way to control the sampling frequency? Is attached a simple VI, I am using to measure my actual sample rate and compare it to the sampling frequency that I am trying to achieve.

  The VI use the DAQ assistant to acquire data of pressure, inserts data into a table, and measure the size of the array. I'm then by dividing the size of the array by the elapsed time in seconds for the sample/s (I'm also dividing the number of iterations of the loop by seconds and using it as a comparison). I compare this value to my entries for the 'number of samples' and controls 'speed' in order to give a sense of the role they play in sampling rate. The VI also allows to choose to use the wait function (ms), as well, using this function is the only way I can control the actual sampling frequency, but then I always get buffer overflow errors. Any information would be helpful, thanks!

  What is the device that you are using? My guess is that whatever you have, it does not allow such a slow pace and is failing at its minimum.