Data Translation DT9800 Series, Руководство пользователя

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Principles of Operation
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Note: If you are using a slow clock data rate, such as .75 Hz, and
a 256 sample user buffer, you will have to wait over 5 minutes for
any data since data is transferred only when 256 samples have
been read.
• Specify one of the following buffer wrap modes:
−
If the wrap mode is none, data is written to the allocated
buffers until no more empty buffers are available; at that
point, the operation stops.
−
If wrap mode is multiple, data is written to the allocated
multiple buffers continuously; when no more empty buffers
are available, the module overwrites the data in the filled
buffers starting with the first location of the first buffer. This
process continues indefinitely until you stop it.
−
If wrap mode is single, data is written to a single buffer
continuously; when the buffer is filled, the module overwrites
the data in the buffer starting with the first location of the
buffer. This process continues indefinitely until you stop it.
Error Conditions
The DT9800 Series function modules can report an error if one of the
following conditions occurs:
• A/D Over Sample error
−
The A/D sample clock rate is too fast.
This error is reported if a new A/D sample clock pulse occurs
while the ADC is busy performing a conversion from the
previous A/D sample clock pulse. The host computer can clear
this error.
To avoid this error, use a slower sampling rate.