06-21-2017 01:18 AM
Hello,
I'm a noobie to DAQmx and I'm working on a PCI 6509 to exam a 4-channel device via C#. I prefer to trigger an event when all of these 4 digital inputs are TRUE . I've checked the user guide which refers:
However, these 4 channels might be set to 1 almost at the same time which means 4 events will raise in a very short interval. As I have no idea which line changes, I have to read all 4 lines 4 times during this, which could leads to performance issue(or not?).
Thank you!
06-21-2017 04:52 AM
From here I read that the change detection will NOT cache the data, which means the data you read are those when ReadSingleSampleMultiLine or BeginReadSingleSampleMultiLine executed, protentially different from when change raising.
However, according to this,
"Once a change occurs, data is latched in the hardware buffer, and then the pattern is transferred via Direct Memory Access (DMA) or Interrupt to the PC memory."
which is the opposite description. This confused me, which one is true? latched&transfer or not?