07-08-2011 02:16 AM
i want to know how a start trigger starts the acquisition of data.please give me any example
07-08-2011 03:44 AM
Do you want to know the theory behind it or are you looking for an example?
What hardware are you using?
07-08-2011 04:06 AM
theory
07-08-2011 04:23 AM
A typical Multifunction DAQ Card (E, M, S, X Series) is continously acquiring samples to its onboard buffer (FIFO, ringbuffer).
As soon as the Start Trigger occurs the latest value of the buffer becomes valid and all the samples available from that point of time will be transfered to the RAM via DMA.
Christian
07-11-2011 08:13 AM
Hello Christian,
Thank you and Best Regards,
I implemented a advance Measurement and Control system using cRIO-9074 with c-Series I/O cards( NI 9217, 9411, 9264) I have some questions about it, (1)- Data rate from FPGA targate to host vi is too low. how can I increase it, when I run my host VI, sometimes all temperature sensor update at same time and sometimes one by one, can you please give me some hint, how can I correct it, I used two FIFOs for NI-9411 digital pulses, I put all Digital input and all analog output and input in a seperate while loop in FPGA targate VI. (2)- I have to write that data to analyse for further result. I tried all possible way to write data including wite to spreadsheet.vi, write to text.vi, Data storage.vi, Write to measurement.vi. All this VI work efficientlywhen it run individualy, But when I connect this VI to writedata from FPGA host VI. than it always give empty file. I saw your post in NI discussion forum about how to write data from Host.vi, But still I am confuse that how can I creat a protocol between host VI and Fpga target vi. to write the data in a file. I have nearabout 38 channel to write data. (3)- I have to measure time difference between two digital pulses, to find a flow rate. I am using counter for it with risisng edge shot.vi, but when i get a timestemp when there is risisng edge for the second rising edge how can I get timestemp. Its like i have to measure time between two pulses, I triend waveform measurement.vi to find cycle period. but it not worked. any other was to measure it. I am stuck in this question since from last one month. I already followed NI-discussion forum solution but it doesnt work. I think the way I applied is may be wrong. Looking forward to hear from you soon. Plese send an additional email copy to tpatel1313@gmail.com
07-13-2011 09:37 AM
Hi,
I think the way you are looking for support does not work via the forums. From what you wrote we have to make to many assumptions to give you hints. And I think hints won't help you.
So please call your local NI Office for support. We offer professional services so that an engineer will assist you.
Thanks,
Christian