Hello,
Unfortunately, such a feature is not yet integrated into our devices.
What we could recommend for Your use case, is monitoring the Custom Sensor values in Your platform and once it reaches a certain threshold, Your platform could send an SMS/GPRS command setdigout, which would enable the DOUT.
You can read more about the setdigout command here: https://wiki.teltonika-gps.com/view/FMB_setdigout
If You have any additional questions about Your use case, feel free to post another comment here.
Best regards.