Chapter 2 Hardware Overview ofthe NI 783xR
NI 783xR User Manual 2-4 ni.com

Input Range

The NI78 3xR AI range is fixed at ±10V.
Connecting Analog Input Signals
The AI signals for the NI 783xR are AI<0..n>+, AI<0..n>–, AIGND, and
AISENSE. For the NI 7830R, n=4. For the NI 7831R/7833R, n=8. The
AI<0..n>+ and AI<0..n>– signals are connected to the eight AI channels of
the NI 783xR. For all input modes, the AI<0..n>+ signals are connected to
the positive input of the instrumentation amplifier on each channel. The
signal connected to the negative input of the instrumentation amplifier
depends on how you configure the input mode of the device.
In differential input mode, signals connected to AI<0..n>– are routed to the
negative input of the instrumentation amplifier for each channel. In RSE
input mode, the negative input of the instrumentation amplifier for each
channel is internally connected to AIGND. In NRSE input mode, the
AISENSE signal is connected internally to the negative input of the
instrumentation amplifier for each channel. In DIFF and RSE input modes,
AISENSE is not used.
Caution Exceeding the differential and common-mode input ranges distorts the input
signals. Exceeding the maximum input voltage rating can damage the NI783xR and the
computer. NI is not liable for any damage resulting from such signal connections. The
maximum input voltage ratings are listed in TableB-2, NI 783xR I/O Signal Summary.
AIGND is a common AI signal that is routed directly to the ground tie point
on the NI 783xR. You can use this signal for a general analog ground tie
point to the NI 783xR if necessary.
Connection of AI signals to the NI 783xR depends on the input mode of the
AI channels you are using and the type ofinput signal so urce. With
different input modes, you can use the instrumentation amplifier in
different ways. Figure2-3 shows a diagram of the NI 783xR
instrumentation amplifier.