Analog Output Triggering - National Instruments 6711 User Manual

Chapter 3 Analog Output
Finite sample mode generation refers to the generation of a specific, predetermined number of
data samples. After the specified number of samples has been written out, the generation stops.
Continuous generation refers to the generation of an unspecified number of samples. Instead of
generating a set number of data samples and stopping, a continuous generation continues until
you stop the operation. There are several different methods of continuous generation that control
what data is written. These methods are regeneration, FIFO regeneration and non-regeneration
modes.
Regeneration is the repetition of the data that is already in the buffer. Standard regeneration is
when data from the PC buffer is continually downloaded to the FIFO to be written out. New data
can be written to the PC buffer at any time without disrupting the output.
With FIFO regeneration, the entire buffer is downloaded to the FIFO and regenerated from there.
After the data is downloaded, new data cannot be written to the FIFO. To use FIFO regeneration,
the entire buffer must fit within the FIFO size. The advantage of using FIFO regeneration is that
it does not require communication with the main host memory when the operation is started,
thereby preventing any problems that may occur due to excessive bus traffic.
With non-regeneration, old data will not be repeated. New data must be continually written to
the buffer. If the program does not write new data to the buffer at a fast enough rate to keep up
with the generation, the buffer will underflow and cause an error.
Non-Buffered
In hardware-timed non-buffered generations, data is written directly to the FIFO on the device.
Typically, hardware-timed non-buffered operations are used to write single samples with known
time increments between them and good latency.

Analog Output Triggering

Analog output supports two different triggering actions: start and pause. A digital hardware
trigger can initiate these actions. All AO Series devices support digital triggering.
AO Start Trigger Signal AO Pause Trigger Signal
The section and section contain information
about the analog output trigger signals.
Refer to Chapter 10, Triggering, for more information about triggers.
3-4 | ni.com