Data Translation DT9820 Series, User Manual

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Chapter 2
10
Analog Input Channels
Each A/D subsystem on the DT9820 Series function modules
supports one differential analog input channel. You configure the
channel type as differential through software.
Using software, you can also select whether to use 10 k
Ω
termination
resistance between the low side of each differential channel and
isolated analog ground. This feature is particularly useful with
floating signal sources. Refer to the DT9820 Series Getting Started
Manual for more information on wiring to inputs and configuring the
driver to use bias return termination resistance.
Using DT-Open Layers software, you can also specify whether to use
a 100 Hz filter to filter the input on each channel. By default, the
filters are turned off. Refer to the documentation for your software
package for information on turning filters on and off.
The simplest way to acquire data from a single channel is to specify
channel 0 of each subsystem for a single-value analog input operation
using software; refer to
page 15 for more information on single-value
operations.
If you want to clock A/D conversions, specify channel 0 in a channel
list.
Input Ranges and Gains
The DT9820 Series modules support a unipolar input range of 0 to
2.5 V, an offset unipolar range of
−
0.10 V to 2.5 V, and a bipolar range
of 2.5 V. In addition, you can choose from up to 7 gains (1, 2, 4, 8, 16,
32, and 64).
Table 2 lists the supported gains and effective input range
of each DT9820 Series function module.