National Instruments NI 785xR - Manual (Page 26)

Chapter 2 Hardware Overview of the NI 78xxR
© National Instruments Corporation 2-5 R Series Intelligent DAQ User Manual
Input Modes
The NI 783xR/784xR/785xR input mode is software configurable. The
input channels support three input modes—differential (DIFF), referenced
single ended (RSE), and nonreferenced single ended (NRSE). The selected
input mode applies to all the input channels. Table 2-2 describes the three
input modes.
Input Range
The NI 783xR/784xR/785xR AI range is fixed at ±10 V.
Negative full-scale range +1 LSB –9.999695 8001
Negative full-scale range –10.000000 8000
Any input voltage —
Table 2-2. Available Input Modes for the NI 783xR/784xR/785xR
Input Mode Description
DIFF When the NI 783xR/784xR/785xR is configured in DIFF input mode, each
channel uses two AI lines. The positive input pin connects to the positive terminal
of the onboard instrumentation amplifier. The negative input pin connects to the
negative input of the instrumentation amplifier.
RSE When the NI 783xR/784xR/785xR is configured in RSE input mode, each
channel uses only its positive AI pin. This pin connects to the positive terminal
of the onboard instrumentation amplifier. The negative input of the
instrumentation amplifier connects internally to the AI ground (AIGND).
NRSE When the NI 783xR/784xR/785xR is configured in NRSE input mode, each
channel uses only its positive AI pin. This pin connects to the positive terminal
of the onboard instrumentation amplifier. The negative input of the
instrumentation amplifier on each AI channel connects internally to the
AISENSE input pin.
Table 2-1. Ideal Output Code and AI Voltage Mapping (Continued)
Input Description AI Voltage
Output Code (Hex)
(Two’s Complement)
Output Code
32,768
---------------------------------- 10.0 V
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