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Chapter 3 Hardware Overview
©
National Instruments Corporation 3-3 PCI-6110E/6111E User Manual
configuration, refer to the
Analog Input Signal Connections
section in
Chapter4,
Signal Connections
, which contains diagrams showing the
signal paths for DIFF input.
Input Polarity and Input Range
The 611
X
E board has bipolar inputs only. Bipolar input means that the
input voltage range is between –V
ref
/2
and + V
ref
/2. These boards have
a bipolar input range of 20V (±10 V).
You can program range settings on a per channel basis so that you can
configure each input channel uniquely.
The software-programmable gain on these boards increases their
overall flexibility by matching the input signal ranges to those that the
ADC can accommodate. They have gains of 0.2, 0.5, 1, 2, 5, 10, 20, and
50, and are suited for a wide variety of signal levels. With the proper
gain setting, you can use the full resolution of the ADC to measure the
input signal. Table3-1 shows the overall input range and precision
according to the gain used.
Table 3-1.
Actual Range and Measurement Precision
Range
Configuration
Gain Actual Input Range
1
Precision
2
–10 to +10 V 0.2
0.5
1.0
2.0
5.0
10.0
20.0
50.0
–50 to +50 V
–20 to +20 V
–10 to +10 V
–5 to +5 V
–2 to +2 V
–1 to +1V
–500 to +500 mV
–200 to +200 mV
24.41 mV
9.77 mV
4.88 mV
2.44 mV
976.56 µV
488.28 µV
244.14 µV
97.66 µV
1
Warning:
The 611
X
E is not designed for input voltages greater than 42 V, even if a
user-installed voltage divider reduces the voltage to within the input range of the DAQ
device. Input voltages greater than 42 V can damage the 611
X
E, any device connected to
it, and the host computer. Overvoltage can also cause an electric shock hazard for the
operator. National Instruments is NOT liable for damage or injury resulting from such
misuse.
2
The value of 1 LSB of the 12-bit ADC; that is, the voltage increment corresponding to a
change of one count in the ADC 12-bit count.
Note:
See Appendix A,
Specifications
, for absolute maximum ratings.
PCI_E.book Page 3 Thursday, June 25, 1998 12:55 PM