With <setdcdivetimealarm> the dive time in minutes is set when the dive computer shall give an alarm signal (independent of (maximum) dive depth reached). As many <setdcdivetimealarm> elements as needed can appear one after the other to support different alarm signals at different dive times reached.
<dcalarm>, <diveduration>
(see also <setdcdata>)
<!-- reaching a dive duration of 45 minutes the dive computer shall give an acoustic signal -->
<setdcdivetimealarm>
    <diveduration>2700.0</diveduration>
    <dcalarm>
        <!-- alarm to be given for 10 seconds -->
        <period>10.0</period>
        <alarmtype>3</alarmtype>
    </dcalarm>
</setdcdivetimealarm>
<!-- after 60 minutes of diving the dive computer shall give another acoustic signal -->
<setdcdivetimealarm>
    <diveduration>3600.0</diveduration>
    <dcalarm>
        <!-- this alarm is to be acknowledged -->
        <acknowledge/>
        <alarmtype>4</alarmtype>
    </dcalarm>
</setdcdivetimealarm>