I am using a PXI 8108 controller (Windows) with a PXI 6255 AI card. A pulse generator (1 KHz) is incrementing the hardware counter of that AI card in order to have an external reference clock, i. e. having a timestamp for each AI sample value.
I am reading 1000 AI values from several channels (together with 1000 counter values) via DAQmx blocks with a higher frequency than the external clock's 1 KHz (e.g. AI Rate 5 KHz-> reading every counter value approx. 5 times). Every now an then I am losing counter values, e. g. counter value 6789 is followed by 6823.
Shouldn't be the PXI card's counter buffer independant of Window's CPU load? Getting 1000 values from the card buffer, the jumps are even located in the middle of the 1000 values. Maybe there's a problem with atomicity while reading from the buffer, so that I get 500 values from the buffer, (pause), and 500 more values from a later point in time. Is this possible?
I am sure, I can not blame the digital pulse generator (from Hameg Instruments) for dropping pulses.
