User Manual

LOGO! functions
4.4 Special functions list - SF
LOGO!
166 Manual, 06/2014, A5E33039675
Functional description
The yearly timer sets and resets the output at specific on and off dates. Sets and resets are
executed at 00:00. If your application requires a different time, use a weekly timer together
with a yearly timer in your circuit program.
The on time specifies when the timer is activated. The off time specifies when the output is
reset again. For the on and off times, note the order of the fields: The first field defines the
year, the second the month and the third the day.
If you set the Monthly mode on, the timer output switches on each month at the specified day
of the on time and remains on until the specified day of the off time. The on time specifies
the initial year in which the timer is activated. The off time defines the last year in which the
timer turns off. The maximum year is 2099.
If you set the Yearly mode on, the timer output switches on each year at the specified month
and day of the on time and remains on until the specified month and day of the off time. The
on time specifies the initial year in which the timer is activated. The off time defines the last
year in which the timer turns off. The maximum year is 2099.
If you set Pulse output, the timer output switches on at the specified on time for one cycle
and then the timer output is reset. You can choose to pulse a timer on a monthly or yearly
basis, or just a single time.
If you set none of the Monthly, Yearly, or Pulse modes on, you can define a specific time
period with the on time and off time. It can span any time period that you choose.
For a process action that is to be switched on and off at multiple but irregular times during
the year, you can define multiple yearly timers with the outputs connected by an OR function
block.
Backup of the real-time clock
The internal real-time clock of LOGO! is buffered against power failure. The buffering time is
influenced by the surrounding temperature, and is typically 80 hours at a surrounding
temperature of 25°C.