National-instruments Data Acquisition Device NI USB-621x Manual de usuario Pagina 34

  • Descarga
  • Añadir a mis manuales
  • Imprimir
  • Pagina
    / 185
  • Tabla de contenidos
  • SOLUCIÓN DE PROBLEMAS
  • MARCADORES
  • Valorado. / 5. Basado en revisión del cliente
Vista de pagina 33
© National Instruments Corporation 4-1 NI USB-621x User Manual
4
Analog Input
Figure 4-1 shows the analog input circuitry of USB-621x devices.
Figure 4-1. USB-621x Analog Input Circuitry
The main blocks featured in the USB-621x analog input circuitry are as
follows:
I/O Connector—You can connect analog input signals to the
USB-621x device through the I/O connector. The proper way
to connect analog input signals depends on the analog input
ground-reference settings, described in the Analog Input
Ground-Reference Settings section. Also refer to Appendix A,
Device-Specific Information, for device I/O connector pinouts.
Mux—Each USB-621x device has one analog-to-digital converter
(ADC). The multiplexers (mux) route one AI channel at a time to the
ADC through the NI-PGIA.
AI Ground-Reference Settings—The analog input ground-reference
settings circuitry selects between differential (DIFF), referenced
single-ended (RSE), and non-referenced single-ended (NRSE) input
modes. Each AI channel can use a different mode.
NI-PGIAThe NI programmable gain instrumentation amplifier
(NI-PGIA) is a measurement and instrument class amplifier that
DIFF, RSE,
or NRSE
I/O Connector
AI <0..n>
Mux
AI SENSE
AI GND
NI-PGIA
AI Ground-Reference
Settings
Input Range
Selection
ADC
AI FIFO
AI Data
Digital
Isolators
Isolation
Barrier
(USB-6215/
6216/6218
devices only)
Vista de pagina 33
1 2 ... 29 30 31 32 33 34 35 36 37 38 39 ... 184 185

Comentarios a estos manuales

Sin comentarios