Time unit

Defualt values:

Name	Alias	Base	Base value
PICOSECOND	ps	ps	1
NANOSECOND	ns	ps	1000
MICROSECOND	µs	ns	1000
MILLISECOND	ms	µs	1000
SECOND	s	ms	1000
MINUTE	M	s	60
HOUR	H	M	60
DAY	D	H	24