Measurement Computing DBK Part 2 - Manual (Page 78)

DBK46, pg. 2 967194 DBK Option Cards and Modules
WBK41 Front Panel,
Right-Edge Terminal Block
Internal DAC Pacer Clock
Internal Acquisition Pacer Clock
External DAC Pacer Clock (DPCR)
DBK46 Block Diagram,
WBK41 Application
The DBK46 has a 256K sample buffer that can be used for one to four DACs. If only one DAC is enabled
for waveform output, then the entire 256K sample memory can be used to store a waveform for that DAC.
If two DACs are enabled for waveform output, then 128K of sample memory is available for each of the
two DACs. Use of all four DACs drops the available memory down to 64K per DAC.
Software loads the waveform(s) into all, or a portion of, the 256K sample buffer. The waveform data
drives the DACs at the rate of the specified DAC Pacer Clock. The waveforms will repeat until the DACs
are disabled by software.
The DBK46 provides an output range of -10V to +10V. The card’s 256 Kbyte of sample buffer memory
can store waveforms from the PC.
When used to generate waveforms for a DaqBook/2000 Series device, each DAC can be independently
clocked in one of four modes. These are:
Internal DAC Pacer Clock - The on-board programmable clock can generate updates ranging
from 1.5 Hz to 100 kHz, independent of any acquisition rate.
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•
•
•
Internal Acquisition Pacer Clock - Using the on-board programmable clock, the analog
output rate of update can be synchronized to the acquisition rate derived from 100 kHz to once
every 5.96 hours.
External DAC Pacer Clock - A user-supplied external input clock can be used to pace the
DAC, entirely independent of other analog inputs.
External Acquisition Pacer Clock - A user-supplied external input clock can simultaneously
pace the DAC and the analog input.
When used to generate waveforms in a WBK41, the DACs can be clocked in one of three modes.
These are:
Internal DAC Pacer Clock - The WBK41 programmable clock can generate updates ranging
from 1.5 Hz to 100 kHz, independent of any acquisition rate.
•
•
•
Internal Acquisition Pacer Clock – By using the WBK41 programmable clock, the analog
output rate of update can be synchronized to the acquisition rate derived from 100 kHz to once
every 5.96 hours.
External DAC Pacer Clock (DPCR) - A user-supplied external input clock can be used to
pace the DAC, entirely independent of other analog inputs. This external clock input connects
to the DPCR connector, located on the Counter/Timer Terminal Block.