Signal Connections
Chapter 3
AT-MIO-16 User Manual
3-10
© National Instruments Corporation
Single-Ended Connection Considerations
Single-ended connections are those in which all AT-MIO-16 analog input signals are referenced
to one common ground. The input signals are tied to the positive input of the instrumentation
amplifier, and their common ground point is tied to the negative input of the instrumentation
amplifier.
When the AT-MIO-16 is configured for single-ended input (NRSE or RSE), 16 analog input
channels are available. You can use single-ended input connections when the following criteria
are met by all input signals:
•
Input signals are high level (greater than 1 V).
•
Leads connecting the signals to the AT-MIO-16 are less than 15 ft.
•
All input signals share a common reference signal (at the source).
If any of the preceding criteria are not met, using DIFF input configuration is recommended.
You can jumper configure the AT-MIO-16 for two different types of single-ended connections—
RSE configuration and NRSE configuration. The RSE configuration is for floating signal
sources; in this case, the AT-MIO-16 produces the reference ground point for the external signal.
The NRSE configuration is for ground-referenced signal sources; in this case, the external signal
supplies its own reference ground point and the AT-MIO-16 should not supply one.
Single-Ended Connections for Floating Signal Sources (RSE Configuration)
Figure 3-5 shows how to connect a floating signal source to an AT-MIO-16 board configured for
single-ended input. You must configure the AT-MIO-16 analog input circuitry for RSE input to
make these types of connections. Configuration instructions are included in the Analog Input
Configuration section of Chapter 2, Configuration and Installation.
V
s
+
+
+
-
-
-
V
m
Measured
Voltage
Floating
Signal
Source
ACH<0..15>
Input Multiplexer
AIGND
Instrumentation
Amplifier
I/O Connector
3
5
7
18
1, 2
AT-MIO-16 Board in RSE Configuration
19
AISENSE
Figure 3-5. Single-Ended Input Connections for Floating Signal Sources