SINTU

Concerns: 1. The datatype I have selected in NI SCOPE Fetch is WDT waveform as it is mentioned in the help that waveform data type will include the time stamp values also. Is there any better and appropriate datatype to be selected for the acquisition to happen accurately? 2. I came across another vi in NI SCOPE palette, FETCH MEASUREMENT(POLY) which obtains waveform & returns specified measurement while NI FETCH returns scaled voltage data, what should be implemented for better acquisition? 3. the basic requirement is to save each 1000 data points acquired from NI Fetch VI with the time at which the data are getting acquired. The most prior parameter for our application is the time. Hence even if it is saved after the acquisition or in parallel with the acquisition, the data and time should be saved in a file format most suitable for postprocessing. Please do reply your valuable suggestions or example vi which can meet this requirement. Thank you

Putting 1ms delay in consumer loop was suggested by NI Support Engineer. Before that I was using timed while loop with period of 1 ms

-- I tried to write in Binary file also, but the values are not readable. -- The post processing has to be done offline that is the reason for saving the data in file -- I care about the timestamps of data when it is acquiring from the PCI card. Initially I tried with the simplest method of directly writing the acquired data into a write vi (text, spreadsheet, tdms, binary etc) in the same loop, but the whole iteration was slowed down. Then only I implemented the Producer/Consumer Architecture. As the record length is fixed i.e. 1000, for each iteration in the producer loop, 1000 data points are getting acquired. How should I queue those each 1000 data points to make a buffer of 10,000 points and then save? I tried this for logging every 1000 elements but the consumer loop was slowed down and there was some data lose in saving also.

Thanks alot for your response. I will try as your suggested. The reason for writing 1000 samples for every iteration was to identify the peak shift in the ultrasonic signal, with the time values. As the record length is 1000, and each file will be containing only 1000 data points, it was easier to identify the peak with time. Can you please elaborate on this how to log function twice? I didn't got a clear picture. I checked so, there is no race condition occurring when I am using Stop as a local variable. Still I will take into account and wire TDMS reference through error case. I even tried saving all the data after the acquisition has stopped, then also the time values were not correct. Please help me build the VI Efficiently. Thank You

To acquire data from an ultrasonic transducer with high sampling rate of 10 MHz, PCI 5114 (with on board memory of 8 MB) high speed digitizer is being used with LABVIEW 2015 version. We are using a pulser receiver for giving pulses to ultrasonic transducer. The sync out of pulser receiver has being connected to the trigger input of PCI card and thus in the VI also the trigger source is mentioned as EXT Trigger (PFA the datasheet of pulser receiver) We need to acquire the ultrasonic signals (reference signal & reflected signal ) with a record length of 1000; and save these signals in a text file/ lvm file/tdms , at every 1 ms. As the time taken for the reflected ultrasonic pulse to return to transducer is very critical, the saving of these signals for post processing is our prime requirement. The VI attached is developed using Producer Consumer Architecture, where the Producer loop is acquiring the data from digitizer & the consumer loop is saving the data at the rate of 240 file/ second approx. (our requirement is to save at a rate of 1000 files/sec; 1 millisecond for saving one file). The acquisition is happening perfectly fine, but the saving rate is not as per our current requirement. 2. Ultrasonic Sensor Acquisition & Saving_PC Arch.vi Please give your valuable suggestions on how to improve the code so as the saving rate of files can be improved. Will increasing the buffer memory or on board memory on PCI card resolve the issue? I Tried with tdms file saving also but the time scale was not properly saved. DAQ_TDMS.vi