If the time cannot be synchronized through a standard time receiver, the time information can alternatively be transferred from the 140 ESI 062 01 communication module. The ESI makes the updated time available directly to the EFB in a DPM_Time structure via the TIME_IN parameter. The data structure can also be filled by the user program and the respective bits can be managed. In this way, for example, the time can be set by the CPU.
As soon as the "clock" parameter of the ERT is configured as an "internal clock" with a power reserve not equal to zero (i.e. not free running) the EFB must use the time supplied by the ESI for the synchronization of the internal ERT clock. Until the first synchronization has taken place, the ERT sends back the set Bit "invalid time" in the STATUS output word (Bit 3 TU).
The conditions for the first synchronization of the internal ERT clock via the DPM_Time structure are:
The EFB Parameter T_EN must change from 0 to 1 to enable the time setting.
The time in TIME_IN made available by ESI must look as follows:
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valid (i.e. the bit for the message "time invalid" in Min value must not be set),
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and the values in Ms must change continually.
Should the time data later become invalid or no longer set, then the TU does not switch to 1 until the configured power reserve has expired.
The synchronization/setting of the internal ERT clock takes place via the DPM_Time structure, if:
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EFB-Parameter T_EN is set to 1 to enable the time setting.
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The time data in TIME_IN made available by ESI are valid (i.e. the "Time invalid" Bit in the Min value must not be set).
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The status of the DPM_Time element Sync changes from 0 to 1. This change is run every full hour by the 140 ESI 062 01 but can also be performed as the result of a suitable telecontrol command.
The precision of the time synchronized by the ESI at the ERT can be influenced by delays, by the PLC cycle time, as well as by the cumulative component, which reflects the differences in the ERT software clock (< 360 milliseconds/hour).
If the "clock" parameter of the ERT was configured as an "internal clock" in free running mode (with a power reserve of zero), the internal clock starts with a default setting at hour 0 on 1/1/1990. In this case the time can also be provided by using the DPM_Time data structure of the 140 ESI 062 01 module, as described above. As there is no power reserve available for use, the time will never be invalid and the Bit "Time not synchronized" within the STATUS output word (Bit 4 TA), given back by the EFB, is always set.
