t1= timegen('2017-01-01T00:00Z','60s',1440)
t1.putProperty(QDataSet.NAME,'t1')
t2= timegen('2017-01-01T00:00Z','300s',1440/5)
t2.putProperty(QDataSet.NAME,'t2')
d1= sin( (t1-'2017-01-01T00:00Z')/'1hr'*2*PI )
d2= sin( (t2-'2017-01-01T00:00Z')/'1hr'*2*PI ) + rand(t2.length())
d1= link( t1, d1 )
d1.putProperty( QDataSet.NAME, 'd1' )
d2= link( t2, d2 )
d2.putProperty( QDataSet.NAME, 'd2' )

formatDataSet(d1,'/tmp/20170707.cdf')
formatDataSet(d2,'/tmp/20170707.cdf?append=T')

plot( 0, d1 )
plot( 1, d2 )