Appendix C
Common Questions
©
National Instruments Corporation
C-3
DAQPad-MIO-16XE-50 User Manual
How can I use the STARTSCAN and CONVERT* signals on the
DAQPad-MIO-16XE-50 device to sample the AI channel(s)?
The DAQPad-MIO-16XE-50 uses the STARTSCAN and CONVERT*
signals to perform interval sampling. As Figure C-2 shows, STARTSCAN
controls the scan interval, which is determined by the following equality:
Figure C-2.
Comparing Interchannel Delay and Scan Interval
CONVERT* controls the interchannel delay, which is determined by the
following equality:
This method allows multiple channels to be sampled relatively quickly in
relationship to the overall scan rate, providing a nearly simultaneous effect
with a fixed delay between channels.
Timing and Digital I/O
What are the PFIs and how do I configure these lines?
PFIs are Programmable Function Inputs. These lines serve as connections
to virtually all internal timing signals.
If you are using NI-DAQ or Measurement Studio, use the
Select_Signal
function to route internal signals to the I/O connector, route external signals
to internal timing sources, or tie internal timing signals together.
If you are using NI-DAQ with LabVIEW and you want to connect external
signal sources to the PFI lines, you can use the AI Clock Config, AI Trigger
1
scan interval
-------------------------------
scan rate
=
Channel 0
Channel 1
Interchannel Delay
Scan Interval
1
interchannel delay
--------------------------------------------
sampling rate
=
