Siemens SIPROTEC 7SA522 Manual page 56

Data type definitions
Example
Bytes 3 to 10:
Time stamp
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Indication type (bits 4 and 5)
01 = 1 for single-point indications
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10 = 2 for double-point indications
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The bits designated as "reserved = 0" are at present always transmitted with the
value = 0. These bit positions are not to be evaluated by the PROFIBUS-DP master,
as in future, further information is envisaged to be transmitted therein.
A change from ON to OFF of the indicated single-point indication used in the
example for the identification byte (see above) is transmitted with the value byte
00010000 = 10 .
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The absolute time stamp is transmitted with the data indicated in Figure 3-9 (millisec-
onds up to year) for the point in time at which the alarm changed state.
Meaning of the clock status:
• Logic OR-combination of the real time status bits:
10 → set: daylight saving summer time
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20 → set: real time clock error
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40 → set: real time clock not valid
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SIPROTEC PROFIBUS-DP - Communication profile
C53000-L1840-B001-03