A double is a float with more precision so why would you want the Modeler to generate an actual float as input? Just use the double, you can do the same kind of stuff with it as with a float.
Btw, I'm not sure why you are using a float/double as a time input since you shouldn't need floating point precision (millisecond is usually the smallest unit, but are you using milliseconds here or always using full seconds? Since there IS a division by 1000 in there as well I'd say milliseconds), looks to me you could benefit a lot from https://world.mendix.com/display/refguide4/Parse+and+format+date+function+calls
Additionally, keep in mind that once you converted some date value to a string, it is no longer adjustable for timezones.
Thanks. I was actually accruing total seconds spent on every task using secondsBetween the start date of the task and the end date and keeping a running total. The root error was a Java conversion error with the string format. I was able to get the string formatted correctly with the update code below.
// BEGIN USER CODE int x= secsIn.intValue(); int hours = x / 3600, remainder = x % 3600, minutes = remainder / 60, seconds = remainder % 60;
return ( (hours < 10 ? "0" : "") + hours + ":" + (minutes < 10 ? "0" : "") + minutes + ":" + (seconds< 10 ? "0" : "") + seconds );