plt.errorbar(xtn, y, yerr=e, fmt='+', elinewidth=2, capsize=0, color='k',
    ecolor='k')
plt.gca().xaxis.set_major_locator(MinuteLocator(byminute=list(range(0, 60, 10))))
plt.gca().xaxis.set_major_formatter(DateFormatter('%H:%M:%S'))
plt.gca().set_xlim(larger_alim(plt.gca().get_xlim()))
plt.show()
Manually setting xticks with xaxis_date() in Python/matplotlib