i implemented a simple digital trigger based data acquisition.
AI CONFIG -> AI START -> AI READ ->Waveform gaph
In AI CONFIG :
a. buffer size : 200
b. channels: ACH0
c. device:1
d. input limits: -2 -> +2
In AI START :
a. scan rate: 500
b. pretrigger scans :50
c. number of scans : 200
d trigger : DIGITAL A (2)
e. trigger edge : rising (1)
AI READ :
nothing but the TASKID IN and ERROR IN cluster.
then the the ouput of the AI READ to a waveform graph output.
when i executed this vi, even before i could give the trigger signal, the vi displayed the data from the channel from which it was supposed to acquire the signal.(i.e ACH0)
i feel that since the trigger i used was a digital A t
rigger (with pretrigger scans) , the vi should acquire the samples in a circular buffer and acquire the postrigger samples only after the trigger is received.
then how can the vi display the data even before i trigger the acquisition(i.e acquire the posttrigger scans and display it also)?
please clarify
