Host PC Software
3-17
Operation
3.5.3.4
Averaging
The ADS1254EVM board can average together a selectable number of
samples for each reading. If you want to perform averaging on the data, this
can drastically reduce the download time, since averaging is performed on the
board, and only the averaged data is downloaded by the host. It also allows
much longer readings to be taken, since the board’s RAM is not filled up by
samples which are averaged together; instead, averaging is done before the
data is written into the board’s RAM.
The figure selected here is the number of successive samples that are
collected together and averaged to form one sample. For example, if you
select 32 here, then for each reading, 32 samples are taken and averaged
together to form that reading. This means that if you request 256 samples to
be acquired, 256 samples are returned, but each sample returned is actually
32 successive samples averaged together; so for that acquisition, 8,192
samples are taken by the ADS1254.
Note that this changes the effective sampling rate of the returned data.
Requesting 32 averages per sample, for example, divides the effective
sampling rate by 32. This is not reflected in the main window; the sampling rate
you select there is always the basic sampling rate, and not the effective
sampling rate after averaging.
The ADS1254EVM can only average samples in quantities which are powers
of 2. This dramatically simplifies the averaging calculations that the board’s
microcontroller must perform. The allowable values are all shown in the
Averaging menu; up to 32,768 samples per reading can be averaged together.
Selecting none from the menu—the default—means that no averages are
taken, and data is returned as read from the ADS1254.
3.5.3.5
Serial Monitor
Checking this box causes the serial monitor window to appear when the setup
dialog is closed. This window displays, as it occurs, all serial communications
between the program and the ADS1254EVM, in hexadecimal bytes.
Summary of Contents for ADS1254
Page 1: ... May 2002 Data Acquisition Products User s Guide SLAU083 ...
Page 34: ...3 18 ...
Page 36: ...Board Layouts 4 2 4 1 Board Layouts Figure 4 1 Board Layout Top Layer ...
Page 37: ...Board Layouts 4 3 Physical Description Figure 4 2 Board Layout Bottom Layer ...
Page 38: ...Schematics 4 4 4 2 Schematics The ADS1254 schematics are shown on the following pages ...
