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maersk · Member 3 Joined: 17 Aug 2014 Posts: 891

How do you implement automatic switching between summer time and winter time with SIMATIC HMI Comfort Panels and TIA Portal?

A plant-wide uniform time base is necessary to ensure that messages and alarms are displayed with the correct time stamp and sent by e-mail as required. Problems with the time base consistency might occur when switching between summer time and winter time.

The SIMATIC HMI Comfort Panels have a system function for switching between the time zones ("SetDaylightSavingTime"), but it has to be triggered. There are several ways of doing this, for example, by configuring the panel as a time slave of an S7-1200/1500 PLC. The triggering of the switchover is then done automatically at the correct time.

Configuration
Establish a connection between the Comfort Panel and the PLC. In the table area of the Connection view, for "HMI time synchronization mode" you select the value "Slave" from the drop-down list box.
Switching between summer time and winter time HMI Comfort Switching between summer time and winter time HMI Comfort

Switching between summer time and winter time HMI Comfort Switching between summer time and winter time HMI Comfort

In the PLC you configure reading of the local time using the system block "RD_LOC_T". Bit %X1 of the return value of the block contains a flag that is set when summer time is currently valid. If Bit %x15 of the return value is set, the local time could not be read out.
Switching between summer time and winter time HMI Comfort Switching between summer time and winter time HMI Comfort

Map this flag to an HMI tag for which you have set the Acquisition mode to "Cyclic continuous".
Switching between summer time and winter time HMI Comfort Switching between summer time and winter time HMI Comfort

For the HMI tag you link the "Value change" event to the system function "SetDaylightSavingTime". Assign the HMI tag itself as "Daylight saving time" parameter for the system function "SetDaylightSavingTime".
Switching between summer time and winter time HMI Comfort Switching between summer time and winter time HMI Comfort

Note that the "Change value" event is not recognized correctly if it occurs when the panel is powered down. To ensure correct display even in this case you have two other options for calling the system function "SetDaylightSavingTime":

Link it to a change in value of the PLC time or
Create a task in the scheduler with a trigger of "1 minute" in which you call the system function.

The system function "SetDaylightSavingTime" can also be called via a corresponding script.
https://support.industry.siemens.com/cs/attachments/109482675/TimeSyn_Project_V13_SP1.zip