For correct operation, this FB should always be ‘Enabled’ (so detection is made correctly). It is also provided with two inputs that will allow manual increment and decrement of the RTC by 1 hour.
Internally the FB is executed for one scan at every new hour of the RTC. This means that overall PLC scan time is kept as low as possible.
As a minimum the FB must be running on the Sunday specified in MonthFwd/WeekNoFwd at 'HourFwd' and also on the Saturday from 23:59:59 to Sunday at hour 'HourBack' specified in MonthBack/WeekNoBack.
The RTC ‘Day of Week’ must be set correctly. (0=Sun, 6=Sat)
Test fully in own code to ensure correct operation.
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