National Instruments DAQCard-1200 - Manual (Page 20)

Chapter 2 Installation and Configuration
DAQCard-1200 User Manual 2-4 © National Instruments Corporation
Analog Input Mode
The DAQCard-1200 has three different input modes—referenced
single-ended (RSE), non-referenced single-ended (NRSE), and differential
(DIFF). Single-ended configuration provides eight input channels. DIFF
configuration provides four input channels. Table 2-2 describes these
configurations.
While reading the following paragraphs, you may find it helpful to refer to
the
Analog Input Signal Connections section of Chapter 3, Signal
Connections , which contains diagrams showing the signal paths for the
three configurations. These three modes are software selectable.
RSE Input (Eight Channels, Default Setting)
RSE input means that all input signals are referenced to a common ground
point that is also tied to the DAQCard-1200 analog input ground. The RSE
configuration is useful for measuring floating signal sources. See the
Types
of Signal Sources section of Chapter 3, Signal Connections , for more
information. With the RSE configuration, the DAQCard-1200 can monitor
eight different analog input channels.
Considerations for using the RSE configuration are discussed in Chapter 3,
Signal Connections . Notice that in RSE mode, the return path of the
signal is through analog ground at the connector through the
AISENSE/AIGND pin.
Table 2-2. Analog Input Modes for the DAQCard-1200
Analog
Input Modes Description
RSE Referenced single-ended mode provides eight single-ended inputs with the
negative input of the instrumentation amplifier referenced to AISENSE/AIGND,
which is tied to ground through about 200
Ω
resistance (default setting).
NRSE Non-referenced single-ended configuration provides eight single-ended inputs
with the negative input of the instrumentation amplifier tied to AISENSE/AIGND
and not connected to ground.
DIFF Differential mode provides four differential inputs with the positive input of the
instrumentation amplifier tied to channels 0, 2, 4, or 6 and the negative input tied
to channels 1, 3, 5, or 7, respectively, thus pairing channels (0, 1), (2,3), (4,5), (6,7).