Siemens SENTRON PAC4200, Manual, Page: 34 / 252

Description
3.4 Load profile
SENTRON PAC4200
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Manual, 09/2008, A5E02316180B-01
3.4.4 Synchronization of the load profile
Synchronization time
The device expects the synchronization pulse at the start of the period.
Synchronization types
The device can obtain the synchronization pulse from an external source
●
As a signal at the digital input,
● As a command via the communication interfaces.
The device can control the synchronization itself
●
By means of the internal clock.
Handling of irregular, external synchronization pulses
SENTRON PAC4200 checks whether the external synchronization pulse is received at the
set time, too soon, too late, or not at all. If the deviation from the set time exceeds a defined
tolerance, this results in a shorter period.
If the complete time frame for received pulses is offset, SENTRON PAC4200 automatically
adapts to the new time frame.
Synchronization via the communication interface
The synchronization frame contains the length of the subperiod in minutes. The
synchronization command is ignored if the period length sent to the device with the
synchronization frame is different to the length parameterized in the device.
Synchronization with the internal clock
The length of the subperiod, and thus also the demand period, is determined solely by the
internal clock.
A subperiod starts on the full hour plus a multiple of the configured subperiod length.
Correction of the time during the current demand period or beyond the end of the demand
period results in shorter demand periods. SENTRON PAC4200 marks these periods with the
valuation indicator "resynchronized".
It does not record any substitute values for the gaps that are created in the time history.
Response to powering up
All load profiles that have already been recorded remain unchanged.
SENTRON PAC4200 resets the internal clock if it detects load profiles with a date in the
future or a time in the past on powering up.