© National Instruments
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4-11
NI 7330 User Manual and Specifications
Analog Inputs
The NI 7330 motion controller has the following ADC input signals:
•
Analog Input <1..4>—The NI 7330 motion controller includes an eight-channel
multiplexed, 12-bit ADC capable of measuring ±10 V, ±5 V, 0-10 V, and 0-5 V inputs.
ADC channels 1 through 4 are brought out externally on the 68-pin motion I/O connector.
ADC channels 5 through 8 are connected internally, as shown in Table 4-3. These signals
can be used for ADC test and system diagnostics.
You can configure each ADC channel for motion feedback, simple analog-to-digital
conversion, or both.
You can read the digital value of analog voltage on any of the eight ADC channels of the
controller. Table 4-3 shows the range of values read back and the voltage resolution for each
setting. The voltage resolution is in volts per least significant bit (V/LSB).
As indicated in Table 4-3, when configured as analog feedback, an analog sensor acts like
a limited range absolute position device with a full-scale position range. You can map any
ADC channel as feedback to any axis.
You can enable and disable individual ADC channels in software. Disable unused ADC
channels for the highest multiplexer scan rate performance. When the ADC channels are
properly enabled, the scan rate is high enough to support analog feedback at the highest PID
sample rate.
•
Analog Reference—For convenience, 7.5 V (nominal) analog reference voltage is
available. You can use this output as a low-current supply to sensors that require a stable
reference. Refer to Appendix A,
, for analog reference voltage specifications.
Table 4-2.
Internal ADC Channels
ADC Input
Signal
5
Fi5 V
6
Floating (NC)
7
Analog Reference (7.5 V)
8
Analog Input Ground
Table 4-3.
Analog Input Voltage Ranges
Input Range
Binary Values
Resolution
±10 V
-2,048 to 2,047
0.0049 V/LSB
±5 V
-2,048 to 2,047
0.0024 V/LSB
0-10 V
0 to 4,095
0.0024 V/LSB
0-5 V
0 to 4,095
0.0012 V/LSB
