Data Translation DT9824, User Manual, Page: 49 / 102

Principles of Operation
49
Analog Input Features
This section describes the following features of the analog input (A/D) subsystem on the
DT9824 module:
• Analog input channels, described on page 49
• Input resolution, described on page 50
• Input ranges and gains, described on page 50
• A/D sample clock sources, described on page 50
• Analog input conversion modes, described on page 51
• Triggers, described on page 51
• Data formats, described on page 52
• Data transfer, described on page 53
• Error conditions, described on page 53
Analog Input Channels
The DT9824 module supports four, simultaneous, analog input channels, configured
differentially. Refer to
Chapter 3 for more information on wiring to the analog input channels.
The DT9824 module can acquire data from a single analog input channel or from a group of
analog input channels. In hardware analog input channels are numbered 1 to 4; in software,
the index of a channel is zero-based. Therefore, to access channel 1, specify an index of 0 in
software. Similarly, to access channel 4, specify an index of 3 in software.
Specifying a Single Analog Input Channel
The simplest way to acquire data from a single analog input channel is to use a single-value
analog input operation using software; refer to
page 51 for more information about
single-value operations.
You can also specify a single channel using the analog input channel list, described next.
Specifying One or More Analog Input Channels
You can read data from one or more analog input channels using an channel-gain list. Because
the DT9824 module features simultaneous sampling, the order of the channels in the
channel-gain list does not matter. You cannot specify the same channel more than once in the
list.
Using software, specify the index (0 to 3) of the analog input channels that you want to
sample. Refer to
page 51 for more information about the supported conversion modes.