National Instruments Data Acquisition Device E Series - Manual (Page 247)

Appendix C Troubleshooting
E Series User Manual C-2 ni.com
reference the signal to the same ground level as the device reference. There
are various methods of achieving this reference while maintaining a high
common-mode Rejection Ratio (CMRR). These methods are outlined in
the
Connecting Analog Input Signals section of Chapter 2, Analog Input .
AI GND is an AI common signal that routes directly to the ground
connection point on the devices. You can use this signal if you need a
general analog ground connection point to the device. Refer to the
Differential Connection Considerations section of Chapter 2, Analog
Input , for more information.
How can I use the AI Sample Clock and AI Convert Clock signals on
an E Series device to sample the AI channel(s)?
E Series devices use the ai/SampleClock and ai/ConvertClock signals to
perform interval sampling. As Figure C-1 shows, ai/SampleClock controls
the sample period, which is determined by the following equation:
1/sample period = sample rate
Figure C-1. Interval Sample
The ai/ConvertClock signal controls the convert period, which is
determined by the following equation:
1/convert period = convert rate
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.
Channel 0
Channel 1
Convert Period
Sample Period