Analog Input Buffers - Keithley DAS-1700 Series Manual

For example, 500 samples/2
channels = 250 is ok, but 500
samples/3 channels = 166.67
is incorrect.
60 • Using the DAS-1700 Series with DriverLINX

Analog Input Buffers

DriverLINX supports single-value, single-scan and buffered analog input.
•
For single-value input, specify the Number of buffers as 0. The buffer
for a single value is the ioValue property.
•
For single-scan input, specify the Number of buffers as 1 and the
number of Samples equal to the number of channels.
•
For buffered input, specify the Number of buffers from 1 to 255 and
the number of Samples as desired.
How to set up the DAS-1700 Series to store samples in buffers.
Buffer Size
An individual DriverLINX buffer may have any size as long as the buffer length
holds an integral number of channel scans (i.e., a multiple of the number of analog
input channels you're acquiring). This restriction enforces the requirement that all
acquired channels have the same number of samples.
Buffer Usage
DriverLINX fills buffers sequentially until the task stops. During the task only
complete buffers are available to the application. Except for tasks that stop on
terminal count, the last buffer may be only partially full. If the task stops on a trigger,
use the StopEvent message (or event) to determine the location of the last sample.
For other cases, use a Status operation to determine the location of the last sample.
Compatibility with the KPCI-1800 Series
Keithley's KPCI-1800 Series consists of PCI bus-based data-acquisition boards with
features similar to the DAS-1800HC models. Developers writing applications they
want to be compatible with both series should be aware of the following special
requirements for DMA mode buffering on the KPCI-1800 Series.
Keithley DAS-1700 Series