Solution
There is sample VI (1553 External PXI Trigger.vi) to use external trigger to send message by use of CDIO 0 - 2 on the board. You need to install
the driver to use the example. When you install AIM MIL-STD-1553 Driver 2023 Q1 for Windows 10 PC as default setting, you can find the sample VI at:.
C:\Program Files\NI\LVAddons\ballardinstr32\1.4.0.5\examples\Astronics Ballard Technology\BTI1553Lib
C:\Program Files\NI\LVAddons\ballardinstr64\1.4.0.5\examples\Astronics Ballard Technology\BTI1553Lib
Ballard MIL STD-1553 has 8 DIO channels. 3 of them are available to accept TTL level triggers.
On the BTI editor, for example, you can select CDIO0 by selecting "A".