Hello Feng,
Video and External(BB60 only) triggering is available in Zero-Span mode. You can configure the triggers on the control panel after entering Zero-Span mode. In the API no triggering is performed directly, but the location of external triggers are returned when the API is configured correctly. You can see the API manual to learn more about setting up external triggers. https://relatedcontentdemo.kinsta.cloud/sigdownloads/BB60C/BB60-API-Manual.pdf
Regards,
A.J.