Chapter 3
Connecting the Signals
DAQPad-MIO-16XE-50 User Manual
3-16
ni.com
Single-Ended Connection Considerations
A single-ended connection is one in which the DAQPad-MIO-16XE-50
AI signal is referenced to a ground that can be shared with other input
signals. The input signal is tied to the positive input of the PGIA, and
the ground is tied to the negative input of the PGIA.
When every channel is configured for single-ended input, up to 16 AI
channels are available.
You can use single-ended input connections for any input signal that meets
the following conditions:
•
The input signal is high level (greater than 1 V).
•
The leads connecting the signal to the DAQPad-MIO-16XE-50 are less
than 3 m (10 ft).
•
The input signal can share a common reference point with other
signals.
DIFF input connections are recommended for greater signal integrity for
any input signal that does not meet the preceding conditions.
You can software configure the DAQPad-MIO-16XE-50 channels for
two different types of single-ended connections—RSE configuration
and NRSE configuration. Use the RSE configuration for floating signal
sources; in this case, the DAQPad-MIO-16XE-50 provides the reference
ground point for the external signal. Use the NRSE input configuration for
ground-referenced signal sources; in this case, the external signal supplies
its own reference ground point and the DAQPad-MIO-16XE-50 should not
supply one.
In single-ended configurations, more electrostatic and magnetic noise
couples into the signal connections than in differential configurations.
The coupling is the result of differences in the signal path. Magnetic
coupling is proportional to the area between the two signal conductors.
Electrical coupling is a function of how much the electric field differs
between the two conductors.