I get an error "Error in if (on == "years") { (from #17) : missing value where TRUE/FALSE needed" when trying to plot sub-second series in xts. That is, my xts object only includes observations for the same second:
value
2013-04-23 13:09:29.0000 471295
2013-04-23 13:09:29.0000 471296
2013-04-23 13:09:29.0002 471297
2013-04-23 13:09:29.0002 471298
2013-04-23 13:09:29.0004 471299
2013-04-23 13:09:29.0004 471300
2013-04-23 13:09:29.0006 471295
A similar question about this error was already asked in this thread but I'm not clear if there is a workaround to plot sub-second series.