NI daq 6008 simultaneously analog input

Hello;
For the NI 6008 card sampling frequency equal to 10 kS / s and it has 8 analog inputs, but if I will use the 8 analog inputs simultaneously, what is the value of the new sample rate for each input analog obtained during an acquisition in labview?
best regards.

Duplicate post - http://forums.ni.com/t5/Multifunction-DAQ/NI-Daq-6008-and-Labview/m-p/3095362

Similar Messages

Error -200279 with simultaneous analog input (different devices) and digital output.

Hi guys,
I am a beginner in Labview and have been dealing with this problem for a couple of weeks now and just can't seem to get it completely right, I have a feeling there are a few small bugs in my code/hardware setup.
I am running an scxi-1000 chassis with a 1600 module and 1302C along with a 1303 accesory for temperature measurements, this is connected to four thermoucouples. Unfortunately I have a limited number of modules available so I am also using a PCI-6221 DAQ card with an scb-68 breakout box used for a digital output and analog input voltage channel. Attached is my labview program. When I run the code at a 50 Hz sampling rate it runs with no errors but the data file comes out extremely wrong, this is also attached. When I run the code at 100 Hz I get error-200279 after a few loops. I used to have 2 daqmx timing VIs (one for each input), but the same error would eventually happen, I have also tried increasing the buffer size on said timing VI. I am also using an old computer (Pentium IV) could this effect the program?
I have learned a lot going through forms for similar problems to mine but I just can't get it to for an extended period of time, I have posted my simplest code.
Thanks in advance,
Luca
Attachments:
tc_2.txt ‏1102 KB
FinalCombined_2.vi ‏128 KB

Ok this makes sense. I have made the suggested modifications but still getting the same error with sampling rates of 100 Hz or higher. Could you check that I have implemented the queue VIs properly (new file attached)? Also when running at 50 Hz in debug mode it does not look like the second while loop (with the dequeue element) comes into play until I hit the stop button, once I hit the stop button I get the following error:
Error 1 occurred at Dequeue Element in FinalCombined_2.vi
Possible reason(s):
LabVIEW: An input parameter is invalid. For example if the input is a path, the path might contain a character not allowed by the OS such as ? or @.
=========================
NI-488: Command requires GPIB Controller to be Controller-In-Charge.
This leads me to believe I have programmed the queue elements incorrectly.
Thanks for your help, any suggestions are greatly appreciated.
Luca
Attachments:
FinalCombined_2.vi ‏102 KB

2 analog input and 1 digital

hi,
i attach the vi..
in the following vi i have a problem with the analogs..
when i'm running the vi.. At the results.. olly one of the analog will show me the measuerements..
at the one time maybe the clock analog will give me the results..
and the other analog nothing.. and opposites..
why they don't work together? and and the 2 analog give measurements at the same time..
andrikos
Attachments:
2_analog_and_digital_inputs.vi ‏190 KB

Hello Andrikoscy,
For most multi-function DAQ boards what you're trying to do is not possible. If you want each analog input to run on a different sample clock then you'll need to look into a NI R Series Intelligent Data Acquisition Device. These DAQ boards have a built in FPGA and allow for more customization than M Series boards, including independent sample clocks.
To address your questions:
1. On a non-intelligent DAQ board all analog input channels must share the same sample clock--if you need two different rates I would suggest sampling both channels at the faster of the two frequencies and then just ignore some of the data points on the slower channel.
2. In order to find out the exact time between samples from an external trigger (instead of the constant dt inserted by the waveform acquisition), you will need to take a period or frequency measurement of your signal using a counter on your card. By taking a buffered period measurement you will get an array of the times between samples and with that you can graph your samples on a precise x-axis. Normal analog input tasks that use an external clock do not associate any exact timing information with when a trigger was received.
I hope this helps, and if you'd like more information on the R Series Intelligent Data Acquisition Devices please feel free to contact National Instruments directly at www.ni.com/contact.
Have a great day!
Brooks

Simultaneous serial and analog input DAQ?

Need to sample from the serial port and 4 channels
of analog input at the same time. Figured I need
to use an internal clock to sync the aquisition
since the serial port response delays every so
often. Does anyone know how to sample from an I/O
port and a DAQ card at a consistent sampling
frequency in LV? Any help would be greatly
appreciated.
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[email protected] wrote:
>
> Need to sample from the serial port and 4 channels
> of analog input at the same time. Figured I need
> to use an internal clock to sync the aquisition
> since the serial port response delays every so
> often. Does anyone know how to sample from an I/O
> port and a DAQ card at a consistent sampling
> frequency in LV? Any help would be greatly
> appreciated.
You don't mention what kind of data rates you are talking about. I have
put together several systems that combine time-stamped serial and daq
channels, but in all cases, the serial data was running at around 1 Hz.
The daq channels were often running much faster (100Hz to 1KHz). If
your channels fit this description, then it is possible to synchronize
your data (more or less)
. You can use software timing to set up the
slow loop and acquire the serial data, and used buffered A/D to read in
the appropriate daq channels. The synchronization isn't perfect, but
may be "good enough".
Best of luck,
Dave Thomson
David Thomson 303-499-1973 (voice and fax)
Original Code Consulting [email protected]
National Instruments Alliance Program Member
Research Scientist 303-497-3470 (voice)
NOAA Aeronomy Laboratory 303-497-5373 (fax)
Boulder, Colorado [email protected]

How to synchronize analog input and output from two different USB daq boards

Hi all,
I have two very differnt USB boards the NI USB 6008, which I am using to acquire the data (Analog Input) and a NI USB 9263, it is an Analog Output only board that I am using to deliver a signal (in this case a square pulse). The reason why I am not using the 6008 Analog Ouputs is because I need to deliver negative voltages and need the full +/-10V range.
Looking at similar posts I am pretty sure that I can't use an external trigger or a shared clock, I also tried to use the synchronization of timed structures but no cigar.
I am including a quick vi that I whipped out showing how the signal jitters due to the lack of synchronization. The AO from the 9263 connects to the AI in the 6008 in this example.
Solved!
Go to Solution.
Attachments:
Test Pulse.vi ‏117 KB

I talked to a specialist in the phone and tols me that it is not possible.

How do I acquire two analog inputs simultaneously using a PCI-6052 E series DAQ?

I am using the data to develope transfer functions.

The simple answer is to put the 2 channels of interest in the Channel Control of your VI. Separated them with a comma.
To be honest your question is not very specific. There must be hundereds or thousands of ways to simultaneously acquire 2 analog inputs.
Try looking at the example VIs that ship with the software. Use the Find Examples function of the startup page for LV. Familiarize yourself with the information there and try some likely ones out. At this point you may have some more specific questions to ask.
The descriptions of the VI's are sometimes hard to read, but are usually enough to operate the VI.
Mike

Need help to choose a DAQ for simultaneous sampling

We need to choose a DAQ for simultaneous sampling. The restrictions are:
a) 2 channels
b) The signals on both channels are not continuous. A valid input on the channels is signaled by a falling edge in a third line that can be used as a trigger.
c) The rate of these signals can be up to 50000 per second but they do not arrive in a periodic way.
d) The timing:
The trigger is a pulse of 600 ns
The signals on the channels are stable 200ns before the leading edge of the trigger pulse and remain stable for 900ns.
We have seen the PCI-6143 but we are not sure if it is the best choice.
We have some questions:
1) Does the 6143 fulfill the timing requirements ?
2) Is it posible and easy to set the board to take one sample after the trigger ?
3) Is there a better choice than the 6143 to solve the problem ?
4) Can we solve this problem programming in VB or VC++ and using the software that comes with the board or do we need to buy extra libraries ?

1) Does the 6143 fulfill the timing requirements ?
Yes, the 6143 should fulfill these requirements. It has a 250 KS/s sampling rate per channel which should give you 5x oversampling at the 50 kHz maximum bandwidth you indicated. The minimum delay from the recognition of the trigger to the first sample on this board is 100 ns which falls within the 900 ns window.
2) Is it posible and easy to set the board to take one sample after the trigger ?
It's not clear to me whether you want to take a single sample after a trigger and stop or use the trigger as an external sample clock to acquire several samples at the rate of the trigger. In either case, it's possible and relatively easy to do so. The only quirk is that the minimum number of samples to acquire for a hardware timed acquisition is two samples. This means if you really only want one point after the trigger, you'll have to setup the hardware to acquire two samples and then throw the second one away in software.
3) Is there a better choice than the 6143 to solve the problem ?
This seems like a pretty solid choice for the application you described. However, you didn't mention what the amplitude of your input signals are. The 6143 has a fixed +/- 5 volt range. If this isn't sufficient, you'll have to provide signal conditioning or choose a board with a wider input range. Also, I'm assuming your trigger signal is a TTL signal. If it's an analog signal, you'll want to choose a board with an analog trigger circuit (the 6143 doesn't have an analog trigger). The PCI-6111 is a 2 channel board with a +/- 42 volt input range, an analog trigger, a 5 MS/s sampling rate, and will also meet all of your requirements. The only down side of the 6111 is that it is more expensive and is a 12 bit converter instead of 16 bit. The PCI-6120 has even more functionality than the 6111 and has a 16 bit converter at 800 KS/s. PXI has some more simultaneous offerings, but I'm assuming you want to stick with PCI. You can also check out some of our modular instrument offerings such as the PCI-5102. I'm not as familiar with the modular instruments, so you'll have to check out the specs for yourself. Whether there is a better choice or not is pretty subjective. That will depend on how much you're willing to spend for the features and specs you really care about. From the information you provided, the 6143 will be the lowest cost solution that meets the requirements you specified.
4) Can we solve this problem programming in VB or VC++ and using the software that comes with the board or do we need to buy extra libraries ?
The DAQmx driver provides interfaces to both of these programming environments at no extra cost.

Analog Input and Output in One Single VI

I need help in setting both analog input and output in one single VI. How do I assign channels to be either input or output? How do I simultaneously uses both in one single VI with a while loop structure?? Which AO am I suppose to use to obtain signal from the function generator I have built to feed into the DAQCard-1200?? Help!!
Attachments:
Test1.vi ‏48 KB

One thing you'll need to be aware of is that you will need to DMA lines: one for AI and one for AO. If you don't, then you can configure the DAQCard to do without DMA using the Config VI. But you certainly can do this.
As far as your function generator, you will want to do a buffered analog output. You will write your buffer of points to the buffer, and then tell NI-DAQ how fast to update your analog output channel with these values.
So, you can be reading from AI and checking the AO process in the same while loop. Just make sure you handle the while loop execution (the wait it exits) correctly. This can get tricky when you're doing two types of measurements.
J.R. Allen

Different Sampling rates for different channels in Analog Input

Hi,
I would like to acquire data at different sampling rates on different channels say ACH 0, ACH 1 and so on. I have a PCI 6052E board and NI DAQ 6.9.2. Also is it possible to simultaneously perform Analog output on two different channels along with the Analog input? What will be the problems/consequences as far as the system resources are concerned. I am a beginner in this area and would greatly appreciate any help/pointers for my queries.
Thanking you in advance
Deepak

Search the eaxamples that ship with LV.
Theer is one called simultaneous input and output or something like that.
It will get you started.
re: multiple scan rates. This is acoomplished by sampling all channels at the highest rate and throw away the expttra samples you do not need.
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Failure to read analog inputs

I have a USB6008 with amplified thermocouple signals coming in to the first 4 analog input ports. I have installed DAQmx3.1 on my mac and am trying to use the nidatalogger to read any values from them. Unfortunately I can not seem to read any of the analog ports. In nidatalogger i am given the choice of physical ports 1-7 all of which do not react to analog inputs on the board. They do however react when I apply voltages to some of the digital input pins, most noticable port 30. I am completely confused and since things like MAX dont exsist for the mac, I have no clue how to go about figuring out what is wrong. Help!

Thanks for posting on the NI Forums! I understand you are having trouble reading data from your analog inputs on the USB-6008. I am confused as to what terminals you are using. You mentioned that you are using the first 4 analog input ports.
- Does this mean you are connecting wires into terminals 2, 5, 8 and 11?
- How many thermocouples are you using?
- Is your input configuration single ended or differential?
Please refer to page 13 of the NI USB 6008 User Guide and Specifications, and clarify which terminals you are physically wiring to. You had also mentioned port 30, however if you look on page 14 you can see that terminal 30 corresponds to the +2.5 V pin.
General DAQ Troubleshooting and FAQ under Mac OS
Rod T.

NI Daq 6008 and Labview

hello;
For the NI 6008 card sampling frequency equal to 10 kS / s and it has 8 analog inputs, but if I will use the 8 analog inputs simultaneously, what is the value of the new échantionnage frequency for each input analog obtained during an acquisition in labview?

The data sheet also says the maximum sample rate for multiple channels is 10kS/s aggegate. I take this to mean that the entire channel sweep is done at 10kHz.
You could always try it and see what happens. Read all 8 channels as a waveform with the sample rate set to 10KHz and see what the dt is in the waveform.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

Control analog output based on analog input

Dear forumers,
I am pretty new to the labview programming so excuse me if this was posted before.
I use: Labview 8.5 + PCI 6229
I want to create a real time feedback: to control analog output based on analog input. The task is very simple - if the ai1 (analog input 1) voltage is larger than a constant, then decrease the voltage of the ao1 (analog output 1) by a constant. Otherwise increase the voltage of ao1 by the same constant.
All should work for 10 seconds.
I have tried to implement this using 2 daq asistants and various methods. The problem is that I get the whole signal recorded from the ai1 ( 10 seconds) and then modified and released to the output (another 10 seconds). The execution takes 20 seconds instead of 10 and it is not realtime at all.
Is it a must to make vi in "run continuous" mode to make it work ?
Please help :}.
I am attaching 2 examples.
1. Main idea what I am trying to accomplish
2. Very simple example that still does not work in real time simultaneously.
Attachments:
example-main.vi ‏180 KB
example-simple.vi ‏147 KB

nooto wrote:
Thank you for your suggestion.
I understand the simple arithmetic you are talking about. However I do not understand why it takes 20 seconds instead of 10 to complete the task. In other way to say - why it reads the whole input first (10 seconds) then write the output ( 10 seconds).
Why doesn't ir read and write simultaneously?
If I use Elapsed Time function - what feedback response time can I expect ? Is it good to use Elapsed Time if i need fast response time? In my application i would I need about 1 milisecond response time. Currently in the example the rate is 50 Hz, later I would like to change the rate to 1000.
You simply don't understand the underlying paradigm of LabVIEW -
dataflow. You have a dependency between the first DAQ Assistant and the
second. The second simply will not start until the first finishes. There
is no way around that given your condition that the output depends on
what you read.
If you want 1 millisecond response time then you will have to swithc to a real-time OS. Windows does not have that kind of resolution and there is way to much jitter.

Dv video time stamp with analog input

Hi,
I have a dv video which I want to time stamp with a analog input. For the video, which is dv brought into the computer with ieee1394, LabView calls up a C++ program which then stores the video. Simultaneously, in the program which calls up the C++, an analog signal is also stored (seperately). I know it sounds tricky as well as messy but this is the best we've been able to work out, given the uncorroperative nature of LabView with dv camera. Does anyone have suggections for time stamping these two signals so that I know exactly where in the video the analog signal occurs? The PCI board we use is the NI 6014, which I know is timestamp capable, but I dont know if it can stamp the video feed since it doesnt come in through the NI card.
All thanks in advance for any help!
Daniel

Daniel,
Does your DV camera have any sort of timing or triggering signals? Without these, it will be virtually impossible to correlate measurements. It is cetainly possible to accurately time an analog input with your DAQ card, but correlating these to the digital video would be extremely difficult. Is this video streaming in real time? Or are you reading it off of an already-recorded tape? If this video is streaming in real time, with an acquisition started in software, I would suggest attempting to start the software DV reading at the same time as your DAQ task. If you do have an external signal that can trigger the video acquisition, then I would suggest using that same signal to start your analog acquisition.
Hope this helps,
Ryan Verret
Product Marketing Engineer
Signal Generators
National Instruments

Very low frequency caused by sample frequency in FFT analog input?

I'm measuring a very low frequency on my analog input, this frequency is in connection with the sample frequency of the Analog Input. At a sample frequency of 1000Hz I see a frequency of 0,05Hz in my FFT, at a sample frequency of 500Hz I see a frequency of 0,02Hz.
Attached is a screenshot of an example how I see this very low frequency.
My hardware: NI USB 6008 --> measuring on AI-0 (in this example the input is unwired). But in my real measurement I see the same FFT + signals I want to see (about 2 Hz).
In my real measurement I windowed the FFT (1-3Hz) so I see only the FFT I want to see. But I suspect that my complete signal moves along with this very low frequency of 0,05Hz. I saw this in my measerement.
What did I do wrong?
Attachments:
screenshot.JPG ‏66 KB

First, do you live in Europe? If so, that 50Hz could be power-line pick up.
Antialias filtering must be done in hardware before the DAQ. Because of the way aliasing works if you have sampled the signal it's already too late, you're hosed and no amount of digital filtering can remove the aliased signal. In terms of filter specifications, the filter cutoff needs to be at twice the highest frequency you are interested in seeing. For example, if you are looking for signals in the 2- to 5-Hz range, your antialiasing filter should cutoff at around 10Hz.
Obviously good signal management is also needed: shielding, appropriate signal termination, proper lead dress and spacing from known noise sources, etc...
Mike...
PS: There were no attachments to your last post.
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Random Differential Voltage Drop (DAQ 6008)

While measuring a constant voltage of 5V with the DAQ-6008 I get voltage drops (from 5V to near 0) randomly and for very short periods of time. I've found the same issue even when using different voltage sources. I am attempting to use the voltage on this particular channel as an analog trigger. So, as you can infer, the random voltage drops cause unnecessary triggering. Any Ideas?
Regards

Thank you for your response.
I am including all of the requested information:
1. The LabView vi
2. .txt data output file (open in notepad)
3. A picture of an example setup I am using to test the triggering system (note, this is one of several setups that all have the same triggering issue)
I'm certain the connections are not the problem considering the simplicity of the test circuit as shown in the attached image.
I have my DAQ-6008's ai3 port hooked up to the voltage input (the battery pack as shown in the picture, E.G.). Normally, the ai3 port would be connected to a binary sensor that ouputs either a 5v output or a 0v output depending on the presence of an object. As you can see in the vi, I am attempting to compare each of the incoming ai3 voltages to a value (4.5); if the incoming voltage rises from 0V to above 4.5V, a true signal is outputted and the trigger should activate once by incrementing the wheel count once. The problem presents itself here by incrementing the wheel count randomly even if a constant voltage source remains above the 4.5 threshold value. You can see in the data file that all of the values are 5.208543. Again, this constant voltage is exemplified by the battery pack in the picture. There is no random incrementing if the voltage source remains at 0V.
Attachments:
ME481 DAQ WORK 10.vi ‏110 KB
IMG_20111128_131137.jpg ‏777 KB
test_11-11-28_1300.txt ‏694 KB

NI daq 6008 simultaneously analog input

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