Reboot Z-Uno. This function uses internally watch dog with an infinite loop. The sketch will restart from the beginning.
If the service button is pulled down, your sketch will not boot anymore and Z-Uno will enter in Rescue mode.
If your sketch requires periodical reboot to work properly, your sketch has huge problems! We suggest to debug it instead of doing a workaround with a reboot. In most cases your code hangs due to stack overflow. Use reboot only for debugging purpose.