To use an alarm with the Delta Electronics temperature controller DTB4824, an external alarm would have to be wired to the second output of the controller. For example, DTB4824LR-ND (Delta # DTB4824LR), the “R” suffix calls out the relay output(dry contact) on the 2nd output. The alarm would need to be wired as in the wire diagram below.
Datasheet https://downloadcenter.deltaww.com/downloadCenterCounter.aspx?DID=1102&DocPath=1&hl=en-US