Measurement Computing Data Translation DT3034 User Manual page 91

Chapter 6
• One of the analog input channels after gain is applied. Using software, specify the
Note: If you are using an analog threshold trigger to trigger both the A/D and the D/A
subsystems, ensure that you use the same analog trigger type for both subsystems (either
external or one of the analog input channels). The polarity of the triggers, however, can be
different.
Analog Output Conversion Modes
DT3034 boards support the following conversion modes:
• Single-value operations are the simplest to use but offer the least flexibility and
• Continuous analog output operations take full advantage of the capabilities of the
Continuously-Paced Analog Output
Use continuously-paced analog output mode if you want to accurately control the period
between conversions of individual analog output channels in the analog output channel list.
The host computer transfers digital values to write to the DACs from allocated circular buffers
in computer memory to the output FIFO on the board. The DT3034 board has a 4 kSample
output FIFO. Use software to allocate the number of buffers and to specify the values. It is
recommended that you allocate a minimum of two buffers.
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trigger source as either a positive threshold trigger or a negative threshold trigger.
Using software, specify the analog input channel used as the analog threshold trigger as
the first channel in the analog input channel list; refer to
On DT3034 boards, the threshold level is set using a dedicated 8-bit DAC (the second D/A
subsystem); the hysteresis is fixed at 50 mV. Using software, program the threshold level
by writing a voltage value to the DAC of the second analog output subsystem; this value
can range from 10 V to +10 V.
efficiency. Use software to specify the range, gain, and analog output channel (among
other parameters), and output the data from that channel. For a single-value operation,
you cannot specify a clock source, trigger source, or buffer.
Single-value operations stop automatically when finished; you cannot stop a single-value
operation.
DT3034 boards. In this mode, you can specify an analog input channel list, clock source,
trigger source, buffer, and buffer wrap mode. Two continuous analog output operations
are supported: continuously-paced and waveform generation mode. These modes are
described in the following subsections.
To stop a continuously-paced analog output operation, you can stop sending data to the
board, letting the board 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 board finishes
outputting the specified number of samples, then stops; all subsequent triggers are
ignored. In an abrupt stop, the board stops outputting samples immediately; all
subsequent triggers are ignored.
page 72 for more information.