# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'timedat.2.png'
set ydata time
set format y "% h" timedate
set timefmt "%s"
unset key
set offsets 0.5, 1.5, 0.2, 0.2
set xtics  norangelimit 
set xtics   ()
set ytics  norangelimit 
set ytics   ()
set title "Time data on Y, millisecond precision" 
set title  font ",14" textcolor lt -1 norotate
fulltime(col) = strftime("%d %b %Y\n%H:%M:%.3S",column(col))
parttime(col) = strftime("%H:%M:%.3S",column(col))
NO_ANIMATION = 1
## Last datafile plotted: "-"
plot '-' using 0:1:(fulltime(1)):xticlabels(2):yticlabels(parttime(1))          with labels point pt 7 left offset 1,1 font ",7"