Appendix B
907994
Hardware Analog Level Trigger B-1
Appendix B
Hardware Analog Level Trigger
An Important Note Regarding Hardware Analog Level Trigger and
Comparator Change State
Issue
:
When the starting out analog input voltage is near the trigger level, and you are performing a rising
[or falling] hardware analog level trigger, it is possible that the analog level comparator will have
already tripped, i.e., to have tripped before the sweep was enabled. If this is the case, the circuit will
wait for the comparator to change state. However, since the comparator has already changed state,
the circuit will not see the transition.
Solution
:
(1) Set the analog level trigger to the desired threshold.
(2) Apply an analog input signal that is
more than
2.5% of the full-scale range
away from the
desired threshold
. This ensures that the comparator is in the proper state at the beginning
of the acquisition.
(3) Bring the analog input signal toward the desired threshold. When the input signal is at the
threshold (± some tolerance) the sweep will be triggered.
(4) Before re-arming the trigger, again move the analog input signal to a level that is more
than 2.5% of the full-scale range
away from
the desired threshold.
Example:
o
an engineer is using the ±2V full-scale range (gain = 5)
o
he desires to trigger at +1V on the rising edge
o
he sets the analog input voltage to an initial start-value which is
less than +0.9V (1V – (2V * 2 * 2.5%))
.
Summary of Contents for OMB-DAQBOARD-3000 Series
Page 7: ...This product requires one of the following Operating Systems Windows 2000 Windows XP ...
Page 14: ...IG 8 DaqBoard Installation Guide 918494 1033 0940 rev 8 0 ...
Page 36: ...2 8 Connections Pinouts 918494 DaqBoard 3000 Series User s Manual ...
Page 40: ...4 2 Calibration 918494 DaqBoard 3000 Series User s Manual ...
Page 80: ...6 12 Setpoint Configuration for Output Control 908794 DaqBoard 3000 Series User s Manual ...
Page 102: ...DBK215 pg A 14 948894 Appendix A ...
Page 104: ...B 2 Hardware Analog Level Trigger 90794 Appendix B ...
