User`s manual

Operation Theory 53
The trigger signal asserts when an analog trigger condition is met.
There are five analog trigger conditions in DAQ-/DAQe-/PXI-2502/
2501 card. The DAQ-/DAQe-/PXI-2502/2501 card uses two
threshold voltages: Low_Threshold and High_Threshold to com-
pose five different trigger conditions. You can configure the trigger
conditions easily via software.
Below-Low Analog Trigger Condition
Figure 4-26 shows the below-low analog trigger condition, the
trigger signal asserts when the input analog signal is lower than
the Low_Threshold voltage. High_Threshold setting is not used
in this trigger condition.
Figure 4-26: Below-Low Analog Trigger Condition
Trigger Level digital setting Trigger voltage
0xFF 9.92V
0xFE 9.84V
--- ---
0x81 0.08V
0x80 0
0x7F -0.08V
--- ---
0x01 -9.92V
0x00 -10V
Table 4-8: Ideal Transfer Characteristic of Analog Trigger SRC1
(EXTATRIG)