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Chapter 3 Hardware Overview
© National Instruments Corporation 3-3 NI PCI-6110/6111 User Manual
input of the PGIA. For more information about DIFF input mode, refer to
the
Connecting Analog Input Signals section of Chapter 4, Connecting
Signals , which contains diagrams showing the signal paths for DIFF input
mode.
Input Polarity and Input Range
The NI PCI-6110/6111 has bipolar inputs only. Bipolar input means that
the input voltage range is between –V
ref
/2 and +V
ref
/2. These devices
have a bipolar input range of 20 V (±10 V).
You can program range settings on a per channel basis so that you can
uniquely configure each AI channel.
The software-programmable gain on these devices increases flexibility by
matching the input signal ranges to those that the ADC can accommodate.
The NI PCI-6110/6111 has gains of 0.2, 0.5, 1, 2, 5, 10, 20, and 50, and it
is 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.
Table 3-1 shows the overall input range and precision according to the
chosen gain.
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 +1 V
–500 to +500 mV
–200 to +200 mV
24.41 mV
9.77 mV
4.88 mV
2.44 mV
976.56
µ
V
488.28
µ
V
244.14
µ
V
97.66
µ
V
1
Caution : The NI PCI-6110/6111 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
device. Input voltages greater than 42 V can damage the NI PCI-6110/6111, any device
connected to it, and the host computer. Overvoltage can also cause an electric shock hazard
for the operator. NI is
not liable for damage or injury resulting from such misuse.
2
The value of 1 least significant bit (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 : Refer to Appendix A, Specifications , for absolute maximum ratings.