D/A Convert Signal; D/A External Time Base Signal - Measurement Computing PCI-DAS6034 User Manual

PCI-DAS6034 & PCI-DAS6035 User's Guide

4.3.2 D/A CONVERT Signal

The D/A CONVERT signal causes a single output update on the D/A converters. The DAQ-
Sync "DS D/A UPDATE" input or any AUXIN pin can programmed to accept the D/A
CONVERT signal. It is also available as an output on any AUXOUT pin.
The D/A CONVERT input signal polarity is software selectable. DAC outputs will update
within 100ns of the selected edge. The D/A CONVERT pulses should be no less than 100 µs
apart.
When used as an output, the D/A CONVERT signal may be used to monitor the pacing of the
output updates. The output has a pulse width of 225 ns with selectable polarity.
Figures 4-16 and 4-17 show the input and output timing requirements for the D/A CONVERT
signal.
Figure 4-16. D/A CONVERT Input Signal Timing
Figure 4-17. D/A CONVERT Output Signal Timing

4.3.3 D/A EXTERNAL TIME BASE Signal

The D/A EXTERNAL TIME BASE signal can serve as the source for the on-board DAC
pacer circuit rather than using the internal time base. Any AUXIN pin can be set
programmatically as the source for this signal. The polarity is programmable.
The maximum frequency for the D/A EXTERNAL TIME BASE signal is 20 MHz. The
minimum pulse width is 23 ns high or low. There is no minimum frequency specification.
Figure 4-18 shows the timing requirements for the D/A EXTERNAL TIME BASE signal.
t = 37.5 ns minimum
w
4–12
Functional Description