Adding to this, you can set it up so its like this

Code:
alias Call.Once.To.Start {
  .timer.Call.Once.To.Start.am 00:00 1 0 Called.Once.At.12am.or.pm
  .timer.Call.Once.To.Start.pm 12:00 1 0 Called.Once.At.12am.or.pm
}
alias Called.Once.At.12am.or.pm {
  .timer.Call.Once.To.Start.* off
  .timer.Call.Every.12.hours 0 43200 display.results.alias
}


this way you set off the second alias at 12 am or pm, which then sets off one every 12 hours
(this isnt the only way to do it, it can be done in one timer, but the codes harder to write)