1-6 Overview
978391
DaqBook/3000USB User’s Manual
Fixed pre-trigger with infinite post-trigger
The user specifies the amount of pre-trigger data to acquire, after which the system continues to acquire data
until the program issues a command to halt acquisition.
Variable pre-trigger with post-trigger stop event
(driver support only)
Unlike the pre-trigger modes already discussed, this mode does not have to satisfy the pre-trigger number of
readings before recognizing the trigger event. Thus the number of pre-trigger readings acquired is variable and
dependent on the time of the trigger event relative to the start. In this mode, data continues to be acquired until
the stop-trigger event is detected.
Variable pre-trigger with infinite post-trigger
(driver support only)
This mode is similar to the previous except the acquisition is terminated upon receipt of a command from the
program.
Calibration
Prior to shipping, all DaqBook/3000USB ranges are calibrated with NIST traceability; and a separate correction
factor for each range is stored within the unit.
Outside the factory, the user can set the included DaqView software to automatically calibrate analog inputs. In
addition to being automatic, the calibration is quick and requires no external instruments. The
Self-cal
feature
utilizes an onboard reference which has a stability of 0.005% per year. Refer to the DaqView documentation for
details regarding
Self-cal
.
A two year calibration period is recommended.
Please contact the factory should you have any concerns regarding calibration.
Analog Output
Two 16-bit, 1MHz analog output channels are built into the DaqBook/3000USB with an output range from
-10V to +10V. The maximum rate at which analog outputs can be updated is dependent on several factors,
including the speed of your USB port. Typically, with the A/D operating at full 1 Mreading/s rates, one analog
output can be updated continuously from PC memory at 1 MHz, or two analog outputs at 500 kHz. In addition, a
program can asynchronously output a value to either of the two D/A converters for non-waveform applications,
presuming that the D/A is not already being used in the waveform output mode. Lastly, each of the analog outputs
can be used in a control mode, where their output level is dependent on whether an associated analog, digital, or
counter input is above or below a user-specified limit condition.
When used to generate waveforms, each D/A can be separately selected to be clocked from one of the following
sources:
Asynchronous Internal Clock
The on-board programmable clock can generate updates ranging from 1 MHz to once every 19 hours,
independent of acquisition rate.
Synchronous Internal Clock
The rate of analog output update can be synchronized to the acquisition rate derived from 1 MHz to once every
19 hours.
Asynchronous External Clock
A user-supplied external input clock can be used to pace the D/A, entirely independent of analog inputs.
Synchronous External Clock
A user-supplied external input clock can pace both the D/A and the analog input.