Time entry for scheduled events

I have an action (open an underflow valve) that I want to schedule to happen at a specific time each day, at up to 24 times a day.

The operator/engineer will enter the times at which the event is to occur in a pop up window. The PLC is programmed to perform the action when the time of day in minutes matches the time entry (in minutes) in any of 24 fields. (eg, 10:30 AM is 630 minutes)

I can use a formatted text entry field for the operator to enter the time, but looking for a clean way to convert that to minutes for the PLC. Or is there a better way than using a formatted text entry field?