Keithley KUSB-3100, User Manual

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Chapter 2
20
To stop a continuously paced analog output operation, you can stop
sending data to the module, letting the module stop when it runs out
of data, or you can perform either an orderly stop or an abrupt stop
using software. In an orderly stop, the module finishes outputting the
specified number of samples, then stops; all subsequent triggers are
ignored. In an abrupt stop, the module stops outputting samples
immediately; all subsequent triggers are ignored.
Data Transfer
If you are using continuous output mode, you must allocate and fill
multiple buffers with the appropriate data before starting the
operation, and specify one of the following buffer wrap modes in
software:
• None – Data is written from multiple output buffers
continuously; when no more buffers of data are available, the
continuous output operation stops. This mode guarantees
gap-free data.
• Multiple – Data is written from multiple output buffers
continuously; when no more buffers of data are available, the
module returns to the first location of the first buffer and
continues writing data. This process continues indefinitely until
you stop it. This mode does not guarantee gap-free data.
A Buffer Done message is returned whenever the last value in a
buffer is output. This allows you to fill the buffer or provide a new
buffer, as needed.
Note: An underrun error can result if your buffer size is too small,
if you do not allocate enough buffers, or if your output frequency is
too fast.