Analog Input Circuitry; Figure 2-1. Analog Input Circuitry; Figure 2-2. Signal Source With Common-Mode Connected To An Analog Input Channel - National Instruments SC Express PXIe-4309 User Manual

Chapter 2 Using the PXIe-4309

Analog Input Circuitry

AI0± Protection
Protection
AI16±
AI8± Protection
AI24± Protection
Input signals on each channel are conditioned, buffered, and then sampled by a SAR ADC.
The PXIe-4309 has eight independent signal conditioning paths and ADCs, enabling
simultaneous sampling of up to eight input channels. Each ADC can scan through four
independent input channels for a total of 32 input channels.

Figure 2-2. Signal Source with Common-Mode Connected to an Analog Input Channel

+
Signal
Source
–
Common-Mode
Voltage
~
Source
Source Impedance
Best measurement performance is achieved with source impedance of 50 Ω or lower; refer to the
Source Impedance Error section of the PXIe-4309 Specifications for information on the error
introduced by source impedances greater than 50 Ω.
2-2 | ni.com

Figure 2-1. Analog Input Circuitry

Multiplexer
Floating
Ground
(1 of 8)
Source
Impedance
Ground Connection for Improved
Common-Mode Noise Rejection
Programmable
Gain Amplifier
+
–
Range = ± 15 V
Range = ± 10 V
Range = ± 1.0 V
Range = ± 0.1 V
AIn+ Lead Wire
AIn– Lead Wire
GND Lead Wire
Low-Pass
Filter
SAR ADC
Floating Circuitry (1 of 8)
AIn+
AIn–
TB-4309 (ST) PXIe-4309