ADLINK PCI-9527 - Manual (Page 34)

22 Operation Theory
PCI-9527 ADLINK Technology Inc.
User’s Manual Copyright 2010
3.2 Analog Input Channel
3.2.1 Analog Input Front-End Configuration
Input Configuration, Differential or Pseudo Differential
The differential input mode provides the anode and cathode inputs
of the BNC connector that respond to signal voltage difference
between them. If the signal source is ground-referenced, the dif-
ferential input mode can be used for the common-mode noise
rejection.
If the signal source is a floating signal, setting to pseudo-differen-
tial input mode will provide a reference ground connected to the
cathode input of the BNC through a 50ohm resistor. This will pre-
vent the floating source from drifting over the input common-mode
range.
The recommended configurations for the signal sources are as fol-
lowes.
Signal Source Type Card Configuration
Floating Pseudo Differential
Ground-Reference Differential
Table 3-1: Input Configurations
ADC
AI+
AI-
Calibration
Source
IEPE
x1 or x1/4
+2.5V
10~24V @ 4mA (adjustable)
x1
x3.16
x10
x31.6