Chapter 2
Installation and Configuration
2-4
©
National Instruments Corporation
While reading the following paragraphs, you may find it helpful to refer to
the
Analog Input Signal Connections
, which contains diagrams showing the signal paths for the
three configurations.
RSE Input (Eight Channels, Reset Condition)
RSE input means that all input signals are referenced to a common ground
point that is also tied to the PCI-1200 analog input ground. The differential
amplifier negative input is tied to analog ground. The RSE configuration is
useful for measuring floating signal sources. With this input configuration,
the PCI-1200 can monitor eight different analog input channels.
Considerations for using the RSE configuration are discussed in Chapter 3,
. Notice that in this mode, the signal return path is
analog ground at the connector through the AISENSE/AIGND pin.
NRSE Input (Eight Channels)
NRSE input means that all input signals are referenced to the same
common-mode voltage, which floats with respect to the PCI-1200 analog
ground. This common-mode voltage is subsequently subtracted by the
input instrumentation amplifier. The NRSE configuration is useful for
measuring ground-referenced signal sources.
Table 2-2.
Analog Input Modes for the PCI-1200
Analog Input
Modes
Description
RSE
RSE mode provides eight single-ended inputs with
the negative input of the instrumentation amplifier
referenced to analog ground (reset condition).
NRSE
NRSE mode provides eight single-ended inputs with
the negative input of the instrumentation amplifier
tied to AISENSE/AIGND and not connected to
ground.
DIFF
DIFF 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 choosing
channel pairs (0, 1), (2, 3), (4, 5), or (6, 7).