United Electronic Industries DNA-AI-208, Руководство пользователя

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DNx-AI-208 Analog Input Layer
Chapter 1 6
Introduction
Tel: 508-921-4600 www.ueidaq.com Vers: 4.6
Date: November 2013 File: AI208 Chap1.fm
© Copyright 2009
United Electronic Industries, Inc.
1.4.2 Analog Input
Ground
Connections
To avoid errors caused by common mode voltages on analog inputs, follow the
recommended grounding guidelines in
Figure 1-4 below.
Figure 1-4. Recommended Ground Connections for Analog Inputs
Because all analog input channels in AI-201/202/207/208/225 layers are
isolated as a group, you can connect layer AGND to the ground of the signal
source and eliminate the resistors shown in
Figure 1-4 for floating differential
input signals.
Input
Configuration
Type of Input
Floating Grounded
Typical Signal Sources:
Thermocouples
DC Voltage Sources
Instruments or sensors
with isolated outputs
Typical Signal Sources:
Instruments or sensors
with non-isolated outputs
Differential
Two resistors (10k <R< 100k) provide
return paths to ground for bias currents.
Single-Ended,
Ground
Referenced
+
_
Ret
AGnd
DNA-STP-37,
AI
nX
V
in
Sig
DNA-STP-AI-U
+
_
Ret
AGnd
DNA-STP-AI-U
AI
nX
V
in
Sig
+
_
Ret
AGnd
DNA-STP-AI-U
AI
nX
V
in
Sig
+
_
Ret
AGnd
DNA-STP-AI-U
AInX
V
in
Sig
grounds are at the same potential.
Add this connection to ensure that both
NOT RECOMMENDED