PCI-DAS6031 & PCI-DAS6033 User's Guide
Functional Details
A/D PACER GATE signal
Use the A/D PACER GATE signal to disable scans temporarily. You can program this signal for input at any of
the AUXIN pins.
If the A/D PACER GATE signal is active, no scans can occur. If the A/D PACER GATE signal becomes active
during a scan in progress, the current scan is completed and scans are then held off until the gate is de-asserted.
A/D EXTERNAL TIME BASE signal
The A/D EXTERNAL TIME BASE signal can serve as the source for the on-board pacer circuit rather than
using the 40 MHz 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 A/D EXTERNAL TIME BASE signal is 20 MHz. The minimum pulse width
is 23 ns high or low. There is no minimum frequency specification.
Figure 4-13
Figure 4-13. A/D EXTERNAL TIME BASE signal timing
shows the timing specifications for the A/D EXTERNAL TIME BASE signal.
t
w
t
w
=23 ns minimum
t
p
t
w
t
p
=50 ns minimum
A/D STOP signal
The A/D STOP signal indicates a completed acquisition sequence. You can program this signal to be available
at any of the AUXOUT pins. The A/D STOP output signal is a 50 ns wide pulse whose leading edge indicates a
DAQ done condition. Figur
shows the timing for the A/D STOP signal.
e 4-14
Figure 4-14. A/D STOP signal timing
t
w
t
w
= 50 ns
4-8
Содержание PCI-DAS6031
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