Chapter 2
Hardware Overview of the NI 78xxR
©
National Instruments Corporation
2-5
R Series Multifunction RIO User Manual
Input Modes
The NI 783
x
R/784
x
R/785
x
R inp
u
t mode is software config
u
rable. The
inp
u
t channels s
u
pport three inp
u
t modes—differential (DIFF), referenced
single ended (RSE), and nonreferenced single ended (NRSE). The selected
inp
u
t mode applies to all the inp
u
t channels. Table 2-2 describes the three
inp
u
t modes.
Input Range
The NI 783
x
R/784
x
R/785
x
R AI range is fixed at ±10 V.
Negative f
u
ll-scale range +1 LSB
–9.999695
8001
Negative f
u
ll-scale range
–10.000000
8000
Any inp
u
t voltage
—
Table 2-2.
Available Input Modes for the NI 783
x
R/784
x
R/785
x
R
Input Mode
Description
DIFF
When the NI 783
x
R/784
x
R/785
x
R is config
u
red in DIFF inp
u
t mode, each
channel
u
ses two AI lines. The positive inp
u
t pin connects to the positive terminal
of the onboard instr
u
mentation amplifier. The negative inp
u
t pin connects to the
negative inp
u
t of the instr
u
mentation amplifier.
RSE
When the NI 783
x
R/784
x
R/785
x
R is config
u
red in RSE inp
u
t mode, each
channel
u
ses only its positive AI pin. This pin connects to the positive terminal
of the onboard instr
u
mentation amplifier. The negative inp
u
t of the
instr
u
mentation amplifier connects internally to the AI gro
u
nd (AIGND).
NRSE
When the NI 783
x
R/784
x
R/785
x
R is config
u
red in NRSE inp
u
t mode, each
channel
u
ses only its positive AI pin. This pin connects to the positive terminal
of the onboard instr
u
mentation amplifier. The negative inp
u
t of the
instr
u
mentation amplifier on each AI channel connects internally to the
AISENSE inp
u
t 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
×
Содержание NI 783 R Series
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