Board AT-MIO-16XE-50

[hood1]

can somebody tell me what is the buffer size of the data acquisition board AT-MIO-16XE-50. because i would like to use this board for continuos analog data acquisition, i would like to know the capacity.in manual it is written input FIFO (words) 512. is it the size of buffer.if it is the size?what is the meaning words 512.and if i define the size in my AO config output VI what size should i define.
thanks regards

[markwysong]

The FIFO size isn't really related to the buffer size. The buffer size is the amount of memory set aside in the PC for data acquisition, which really doesn't have anything to do with the data acquisition board itself.

The FIFO memory that you're referring to is the amount of on-board memory the card has to store readings in the case that it can't transfer directly to RAM in your PC via DMA transfers. It will go into the FIFO until the DMA transfer is ready, then go directly to the PC's RAM. So it's really the amount of PC RAM that you're really interested in, because that will determine how much data acquisition you can store in memory at one time.

Mark

[hood1]

But there must be some limit of buffer.what is the limit of buffer.if i want to send 1 million samples to the osilloscope?can we load this buffer in PC with 1 million samples and further this board can we load with 1million samples or we use the circular buffer technik, so that when the buffer on board is empty it will fill the next samples according to its capacity and so on so forth till the we reach the point where our 1-million samples that are stored in array finish and we reach the last sample.
so please make it clear to me what is the capacity of on board buffer and the VIs basic AO vis, the intermediate AO vis, utility AO Vis and advanced VIs, when we set the size of buffer are we setting this buffer size on board or in the computer memory. if it is
buffer size on computer memory,then how can we send 1-million periods to this buffer?there is ship example generate continuos sinewave.can we use it for filling the buffer and empty the computer buffer.why the array input is not wired to another write function in this VI?it seems that write VI does nothing in this case.if we have to send these samples to board and the buffer on the board will start sending/generating these samples to osilloscope,then how can we set this buffer on the board?is there any size of the board.i mean how many samples this board can hold and transfer to osilloscope.is there any example available, how can we use circular buffer for the onboard memory.i mean how i send the samples to onboard buffer that will hold the samples,start sending to oscilloscope and when the buffer is empty.it fetches new data from the array.it must be also fast enough in order to avoid error.
please explain me.
regards

[markwysong]

Wow, one thing at a time!!

When you say you want to send one million samples to the oscilloscope, what does that mean? Do you mean you want to output a voltage signal from the DAQ board to the oscilloscope, or read an analog input on the DAQ board, store it in memory, then download that to the oscilloscope?

I'm assuming that you want to output a voltage to the oscilloscope. Is your signal repeating (like a sine wave), or not? Do you just have 1 million voltage samples you'd like to send to an oscilloscope?

Let me know, and we can start from there.

[hood1]

ok thanks for your reply.

you are right. i want to output voltage to the oscilloscope . it is a sine wave.it could be 1 million,it could be 50,000thousands, any number it could be. obviosly i can wire Function generator to the signal input directly to the AO write,but i am not using this function generator deliberatly, because i want to send the signal(voltage) fixed number of periods andif i use our function generator i dont have periods as input there.and one other thing that my sine is also not true sine(example attached).this 1 million period will be run on oscilloscope for the some corresponding time. this periods must run on the ossilloscope and afterwards they must stop.another example if i send 50 periods.50 periods must run and then they must stop.the time of execution of these 50 must be corresponding time, means when 50 periods finish their execution,the indicator shows that they took xyz seconds for their completion. i am sending you three VIS.moreover i break and pause the Vi as well. i also tried implemet this concept. but it does not work.may be some bug in Ao start.

1VI) in this VI i am generating the array(i am looking for such an array with different amplitude and as i said N number of sine periods i would like to send to AO write.

2VI) in this VI i am showing how i am getting the required time, when i am giving/converting periods and frequency to total time. i dont know why it is not working. you know the periods i send finish early and the VI still not ends its execution.this is wrong time, because if i send 50 periods with 1.6Hz frequency then they must finish in corresponding time.if periods finishes and the time indicator shows,still some time left,that means there is something wrong.this is also one of my big problem

3VI)here my complete VI, where i am trying to buffer all these periods, pause them and resume them, but unfortunately it is also not working properly because when i send 20 periods and dont stop it.then it works fine, but when i send 20 periods, break it and i wanna resume it from the moment/period when i pause it starts agai from the begining. why?
i hope i explain all of my problem.

[markwysong]

Man, I've got to get LV 7.1. I only have 7.0, so I can't open your VIs. If you can, can you do a File -> Save with options and select 7.0 -- that will save it in LV 7.0, and then I can view it.

Mark

[hood1]

ok now i save all these vis to previous version.please have a look it and please correct it.
and please tell me what wrong i am doing?
thanks
regards

[markwysong]

Now we're getting somewhere. I see all your VIs now. What I'm wondering is what you call a "period". Is a period one complete output of the entire array that you've put into the AO Write?

And why is your input to AO Write a 2-dimensional array? Are you writing to both analog outputs?

Lastly, I'm wondering the reason you are using the default 1000 samples per second for your output rate....

Here's how I usually do it. I generate an array which contains exactly one cycle (for example, a single period of a sine wave) and send that into the AO Write as a 1-dimensional array. The number of points, or elements, of that array depend on the resolution that I want.

Next, to determine the frequency
at which the analog output will send out this signal, take the analog output update rate divided by the number of points in your array. (One analog output update is one element of your array.)

Now, wire in to the AO start the number of iterations of the buffer (your array, which is one cycle) that you want it to output. Or, as you've done, put in a 0, and it will output this cycle continuously.

Got it?

Mark

[hood1]

Dear mark
Ao write accepts only 2-D.how can you give Ao write 1-D. frequency i dont have to determine.
it was a very simple thing.i wanted to generate a sine wave.i want to give the user input these values. frequency, amplitude and periods and on this basis i just wanted to execute the sine wave on the osilloscope.if some where in between i make a pause, i wanted to resume it, where i break the application.
i dont know why this simple thing not possible witNI VIS speacially with AO start and this board. i tried
it many times. No NI application Engineer could provide the solution of my problem and i think there must be some bug in the AO start, that we can not resume it once after break. i am sorry
but now i am thinking to use other software but not labview/board in order to solve my problem.
Thanks Regards