National Instruments PXI-7340, Руководство пользователя и технические характеристики

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Chapter 4 Signal Connections
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. 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,
Specifications , for analog reference voltage specifications.
• Analog Input Ground—To help keep digital noise out of the analog input, a separate return
connection is available. Use this reference ground connection and not Digital Ground
(digital I/O reference) or Analog Output Ground as the reference for the analog inputs.
Tip Refer to the Measuring Floating (Nonreferenced) Sources section of the Field
Wiring and Noise Considerations for Analog Signals NI Developer Zone document
at
ni.com/zone
for more information about analog input connections.
Wiring Concerns
For proper use of each ADC input channel, the analog signal to be measured should be connected
to the channel input and its ground reference connected to the Analog Input Ground.
Note The analog reference output is an output signal only and must not connect to
an external reference voltage. Connect the common of the external reference to the
Analog Input Ground pin for proper A/D reference and improved voltage
measurement.
Other Motion I/O Connection
The NI 7340 motion controller provides Host +5 V, which is the in5 V supply of the host
computer. It is typically used to detect when the host computer is powered and to shut down
external motion system components when the host computer is turned off or disconnected from
the motion accessory.
Caution The host +5 V signal is limited to <100 mA and should not be used to
power any external devices, except those intended in the host bus monitor circuits on
the UMI and drive products.