Time switch based on the S7-300/400 CPUs with simple HMI system
including radio-controlled clock connection
Rev. B - final 19.07.2002 39/84
Copyright © Siemens AG 2005 All rights reserved
BID21669756_Zeitschaltuhr_einfach_DOKU_v20_e.doc
Option: Radio-clock controlled (FB 77 “DCF77_FB”)
Optionally the possibility is offered to use a radio-controlled clock for
summer/winter time changeover instead of the block described above. In
case the radio-controlled option has been selected in the ProTool view, the
block FB103 „summer_winter“ is deactivated, instead of that the block
FB77 „DCF77_FB“ is being called, which evaluates the signals received by
the radio clock.
The block has the following input parameters:
• SekTakt of „BOOL“ type
Input „second clock pulse“ from DCF77 module
• Data of „BOOL“ type
Input bit pattern, data from DCF77 module
• SekCPU of „BOOL“ type
CPU clock memory bit with frequency 1 Hz
• DCF77 of „TIMER“ type
Timing element for minute recognition
The block has the following output parameters:
• Zeitzone of „BOOL“ type
Value = 1: It is summer time
Value = 0: It is winter time
• Umsch_Zeitzone of „BOOL“ type
Value = 1: changeover from summer to winter time or the other way
round will occur in one hour
• Min_Puls of „BOOL“ type
with the negative edge a new minute begins and/or the clock is being set
• Fehler of „BOOL“ type
Value = 1: for three minutes or longer no valid telegram has been
received
The block for the connection of the radio-controlled clock FB77
„DCF77_FB“ is parameterized as illustrated in the figure below. Data block
DB77 is used as instance data block:
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