Data Translation DT9812 Series, User Manual

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Principles of Operation
59
Analog Input Features
This section describes the following features of analog input (A/D) operations on the DT9812,
DT9813, and DT9814 Series modules:
• Input resolution, described below
• Analog input channels, described below
• Input ranges and gains, described on page 60
• Input sample clock sources, described on page 61
• Analog input conversion modes, described on page 62
• Input triggers, described on page 63
• Data format and transfer, described on page 63
• Error conditions, described on page 64
Input Resolution
The DT9812, DT9813, and DT9814 Series modules provide a resolution of 12-bits. Note that the
resolution is fixed; you cannot program it in software.
Analog Input Channels
The DT9812-2.5V, DT9812-10V, DT9812-10V-OEM, and DT9812A modules provide eight
single-ended analog input channels. The DT9813-10V and DT9813A modules provides 16
single-ended analog inputs. The DT9814-10V and DT9814A modules provide 24 single-ended
analog input channels. The modules can acquire data from a single analog input channel or
from a group of analog input channels.
The following subsections describe how to specify the channels.
Specifying a Single Analog Input Channel
The simplest way to acquire data from a single analog input channel is to specify the channel
for a single-value analog input operation using software; refer to
page 62 for more information
about single-value operations.
You can also specify a single channel using the analog input channel list, described in the next
section.
Specifying One or More Analog Input Channels
You can read data from one or more analog input channels using an analog input channel list.
You can group the channels in the list sequentially (starting either with 0 or with any other
analog input channel) or randomly. You can also specify a single channel or the same channel
more than once in the list.