Wie Datum und Uhrzeit aus 8 Bytes dekodieren. Komme gerade nicht drauf.

SondenFuchs Gast #3128330
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Hallo,
Ich bschäftige mich gerade mit dem Rohdatenformat eines Datenloggers 
(Selbstbau von jemandem, der leider nicht mehr greifbar ist), an den 
drei Temperatursensoren angeschlossen sind.
Die Daten werden als Folge von je 3 Bytes pro Kanal gespeichert, die 
letzten beiden repräsentieren den 16bit Messwert. "FF FF FF FF" markiert 
den Beginn eines neuen Datensatzes.
Soweit ist alles klar.

FF FF FF FF
FC 08 51 89
FD 0C E8 7D
01 10 XX XX
02 10 XX XX
03 10 XX XX
FF FF FF FF
FC 08 51 89
FD 0C E9 00
01 10 XX XX
02 10 XX XX
03 10 XX XX
FF FF FF FF
FC 08 51 89
FD 0C E9 7C
01 10 XX XX
02 10 XX XX
03 10 XX XX


Allerdings komme ich gerade nicht darauf, wie in den 8 Bytes dazwischen 
Datum und Uhrzeit verpackt sind.
Ich vermute mal, dass es sich um eine Art Unix Timestamp (Sekunden seit 
1/1/1970 UTC) oder ähnliches handelt.

Ich habe schon etwas mit den Werten herumgespielt, habe aber nie ein 
plausibles Ergebnis (Datum muss in diesem Jahr liegen) erhalten.

Hat vielleicht jemand Erfahrung mit dieser Art Datumsformat und kann mir 
helfen, die Bytes richtig zusammenzusetzen und in ein direkt lesbares 
Datumsformat umzurechnen?

Ich bin für jede Hilfe Dankbar!
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SondenFuchs Gast #3128387
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Hallo,

Schön, dass es jemanden interessiert :)

Es sieht für mich so aus:
Es werden mit bis zu 4 Hz Daten geloggt, Datum und Uhrzeit jedoch nur 
sekündlich "dazwischen" gespeichert.

Im Anhang ein kurzes Logfile einer Messung mit 9 Kanälen vom 10.04.2013 
08:20h.
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Frank K. #3128563
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Meine Vermutung:
2 Bytes: was wird gespeichert
2 Bytes: Daten

FC 08: Timestamp Bytes 1+2
FD 0C: Timestamp Bytes 3+4

Das ergäbe einen Anfangs-Timestamp von 0x5189e27f, was als 
Unix-Timestamp laut Wolfram Alpha 05:28:31 UTC am 08.05.2013 entspricht.

Vielleicht rechnet der Entwickler hier anders oder hat einen Bug 
eingebaut.

fchk
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Simon S. #3128715
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Im Anhang gibts die Demodaten aufbereitet.

Man nehmen nur die Timestamps (auch im Anhang) und jage sie durch 
folgendes Python-Skript:
1
#!/usr/bin/env python3

2
import datetime

3


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fobj = open("./demodata.hexform.timestamps.nowhitespaces", "r")

5


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print("Timestamps:")

7


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for line in fobj:

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  line_dec = str(int("0x"+line,16))

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  line_time = line[6:14]

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  line_time_dec = str(int("0x"+line_time,16))

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  print("hex: "+line[:-1] + "   dec: " + line_dec + "  time only: " + line_time  + "  time only dec: " + line_time_dec + "   converted: " + str(datetime.datetime.fromtimestamp(int(line_time_dec)).strftime('%Y-%m-%d %H:%M:%S')))

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fobj.close()


Und bekommt:
1
Timestamps:

2
hex: 08fc89510cfd7fe2   dec: 647543427637805026  time only: 510cfd7f  time only dec: 1359805823   converted: 2013-02-02 12:50:23

3
hex: 08fc89510cfd02e3   dec: 647543427637773027  time only: 510cfd02  time only dec: 1359805698   converted: 2013-02-02 12:48:18

4
hex: 08fc89510cfd7fe3   dec: 647543427637805027  time only: 510cfd7f  time only dec: 1359805823   converted: 2013-02-02 12:50:23

5
hex: 08fc89510cfd01e4   dec: 647543427637772772  time only: 510cfd01  time only dec: 1359805697   converted: 2013-02-02 12:48:17

6
hex: 08fc89510cfd7ee4   dec: 647543427637804772  time only: 510cfd7e  time only dec: 1359805822   converted: 2013-02-02 12:50:22

7
hex: 08fc89510cfd01e5   dec: 647543427637772773  time only: 510cfd01  time only dec: 1359805697   converted: 2013-02-02 12:48:17

8
hex: 08fc89510cfd7ee5   dec: 647543427637804773  time only: 510cfd7e  time only dec: 1359805822   converted: 2013-02-02 12:50:22

9
hex: 08fc89510cfd03e6   dec: 647543427637773286  time only: 510cfd03  time only dec: 1359805699   converted: 2013-02-02 12:48:19

10
hex: 08fc89510cfd7ee6   dec: 647543427637804774  time only: 510cfd7e  time only dec: 1359805822   converted: 2013-02-02 12:50:22

11
hex: 08fc89510cfd00e7   dec: 647543427637772519  time only: 510cfd00  time only dec: 1359805696   converted: 2013-02-02 12:48:16

12
hex: 08fc89510cfd7de7   dec: 647543427637804519  time only: 510cfd7d  time only dec: 1359805821   converted: 2013-02-02 12:50:21

13
hex: 08fc89510cfd00e8   dec: 647543427637772520  time only: 510cfd00  time only dec: 1359805696   converted: 2013-02-02 12:48:16

14
hex: 08fc89510cfd7de8   dec: 647543427637804520  time only: 510cfd7d  time only dec: 1359805821   converted: 2013-02-02 12:50:21

15
hex: 08fc89510cfd00e9   dec: 647543427637772521  time only: 510cfd00  time only dec: 1359805696   converted: 2013-02-02 12:48:16

16
hex: 08fc89510cfd7ce9   dec: 647543427637804265  time only: 510cfd7c  time only dec: 1359805820   converted: 2013-02-02 12:50:20

17
hex: 08fc89510cfd00ea   dec: 647543427637772522  time only: 510cfd00  time only dec: 1359805696   converted: 2013-02-02 12:48:16

18
hex: 08fc89510cfd7cea   dec: 647543427637804266  time only: 510cfd7c  time only dec: 1359805820   converted: 2013-02-02 12:50:20

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hex: 08fc89510cfdf9ea   dec: 647543427637836266  time only: 510cfdf9  time only dec: 1359805945   converted: 2013-02-02 12:52:25

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hex: 08fc89510cfd7ceb   dec: 647543427637804267  time only: 510cfd7c  time only dec: 1359805820   converted: 2013-02-02 12:50:20

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hex: 08fc89510cfdf9eb   dec: 647543427637836267  time only: 510cfdf9  time only dec: 1359805945   converted: 2013-02-02 12:52:25

22
hex: 08fc89510cfd7bec   dec: 647543427637804012  time only: 510cfd7b  time only dec: 1359805819   converted: 2013-02-02 12:50:19

23
hex: 08fc89510cfdf8ec   dec: 647543427637836012  time only: 510cfdf8  time only dec: 1359805944   converted: 2013-02-02 12:52:24

24
hex: 08fc89510cfd7bed   dec: 647543427637804013  time only: 510cfd7b  time only dec: 1359805819   converted: 2013-02-02 12:50:19

25
hex: 08fc89510cfdf7ed   dec: 647543427637835757  time only: 510cfdf7  time only dec: 1359805943   converted: 2013-02-02 12:52:23

26
hex: 08fc89510cfd7bee   dec: 647543427637804014  time only: 510cfd7b  time only dec: 1359805819   converted: 2013-02-02 12:50:19

27
hex: 08fc89510cfdf7ee   dec: 647543427637835758  time only: 510cfdf7  time only dec: 1359805943   converted: 2013-02-02 12:52:23

28
hex: 08fc89510cfd7aef   dec: 647543427637803759  time only: 510cfd7a  time only dec: 1359805818   converted: 2013-02-02 12:50:18

29
hex: 08fc89510cfdf7ef   dec: 647543427637835759  time only: 510cfdf7  time only dec: 1359805943   converted: 2013-02-02 12:52:23

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hex: 08fc89510cfd7af0   dec: 647543427637803760  time only: 510cfd7a  time only dec: 1359805818   converted: 2013-02-02 12:50:18

31
hex: 08fc89510cfdf7f0   dec: 647543427637835760  time only: 510cfdf7  time only dec: 1359805943   converted: 2013-02-02 12:52:23

32
hex: 08fc89510cfd7af1   dec: 647543427637803761  time only: 510cfd7a  time only dec: 1359805818   converted: 2013-02-02 12:50:18

33
hex: 08fc89510cfdf6f1   dec: 647543427637835505  time only: 510cfdf6  time only dec: 1359805942   converted: 2013-02-02 12:52:22

34
hex: 08fc89510cfd78f2   dec: 647543427637803250  time only: 510cfd78  time only dec: 1359805816   converted: 2013-02-02 12:50:16

35
hex: 08fc89510cfdf6f2   dec: 647543427637835506  time only: 510cfdf6  time only dec: 1359805942   converted: 2013-02-02 12:52:22

36
hex: 08fc89510cfd79f3   dec: 647543427637803507  time only: 510cfd79  time only dec: 1359805817   converted: 2013-02-02 12:50:17

37
hex: 08fc89510cfdf5f3   dec: 647543427637835251  time only: 510cfdf5  time only dec: 1359805941   converted: 2013-02-02 12:52:21

38
hex: 08fc89510cfd78f4   dec: 647543427637803252  time only: 510cfd78  time only dec: 1359805816   converted: 2013-02-02 12:50:16

39
hex: 08fc89510cfdf5f4   dec: 647543427637835252  time only: 510cfdf5  time only dec: 1359805941   converted: 2013-02-02 12:52:21

40
hex: 08fc89510cfd78f5   dec: 647543427637803253  time only: 510cfd78  time only dec: 1359805816   converted: 2013-02-02 12:50:16

41
hex: 08fc89510cfdf4f5   dec: 647543427637834997  time only: 510cfdf4  time only dec: 1359805940   converted: 2013-02-02 12:52:20

42
hex: 08fc89510cfd77f6   dec: 647543427637802998  time only: 510cfd77  time only dec: 1359805815   converted: 2013-02-02 12:50:15

43
hex: 08fc89510cfdf5f6   dec: 647543427637835254  time only: 510cfdf5  time only dec: 1359805941   converted: 2013-02-02 12:52:21

44
hex: 08fc89510cfd77f7   dec: 647543427637802999  time only: 510cfd77  time only dec: 1359805815   converted: 2013-02-02 12:50:15

45
hex: 08fc89510cfdf4f7   dec: 647543427637834999  time only: 510cfdf4  time only dec: 1359805940   converted: 2013-02-02 12:52:20

46
hex: 08fc89510cfd76f8   dec: 647543427637802744  time only: 510cfd76  time only dec: 1359805814   converted: 2013-02-02 12:50:14

47
hex: 08fc89510cfdf3f8   dec: 647543427637834744  time only: 510cfdf3  time only dec: 1359805939   converted: 2013-02-02 12:52:19

48
hex: 08fc89510cfd76f9   dec: 647543427637802745  time only: 510cfd76  time only dec: 1359805814   converted: 2013-02-02 12:50:14

49
hex: 08fc89510cfdf3f9   dec: 647543427637834745  time only: 510cfdf3  time only dec: 1359805939   converted: 2013-02-02 12:52:19

50
hex: 08fc89510cfd75fa   dec: 647543427637802490  time only: 510cfd75  time only dec: 1359805813   converted: 2013-02-02 12:50:13

51
hex: 08fc89510cfdf2fa   dec: 647543427637834490  time only: 510cfdf2  time only dec: 1359805938   converted: 2013-02-02 12:52:18

52
hex: 08fc89510cfd75fb   dec: 647543427637802491  time only: 510cfd75  time only dec: 1359805813   converted: 2013-02-02 12:50:13

53
hex: 08fc89510cfdf2fb   dec: 647543427637834491  time only: 510cfdf2  time only dec: 1359805938   converted: 2013-02-02 12:52:18

54
hex: 08fc89510dfd7600   dec: 647543427654579712  time only: 510dfd76  time only dec: 1359871350   converted: 2013-02-03 07:02:30

55
hex: 08fc89510dfdf200   dec: 647543427654611456  time only: 510dfdf2  time only dec: 1359871474   converted: 2013-02-03 07:04:34

56
hex: 08fc89510dfd7501   dec: 647543427654579457  time only: 510dfd75  time only dec: 1359871349   converted: 2013-02-03 07:02:29

57
hex: 08fc89510dfdf101   dec: 647543427654611201  time only: 510dfdf1  time only dec: 1359871473   converted: 2013-02-03 07:04:33

58
hex: 08fc89510dfd7402   dec: 647543427654579202  time only: 510dfd74  time only dec: 1359871348   converted: 2013-02-03 07:02:28

59
hex: 08fc89510dfdf102   dec: 647543427654611202  time only: 510dfdf1  time only dec: 1359871473   converted: 2013-02-03 07:04:33

60
hex: 08fc89510dfd7403   dec: 647543427654579203  time only: 510dfd74  time only dec: 1359871348   converted: 2013-02-03 07:02:28

61
hex: 08fc89510dfdf103   dec: 647543427654611203  time only: 510dfdf1  time only dec: 1359871473   converted: 2013-02-03 07:04:33

62
hex: 08fc89510dfd7404   dec: 647543427654579204  time only: 510dfd74  time only dec: 1359871348   converted: 2013-02-03 07:02:28

63
hex: 08fc89510dfdf004   dec: 647543427654610948  time only: 510dfdf0  time only dec: 1359871472   converted: 2013-02-03 07:04:32

64
hex: 08fc89510dfd7305   dec: 647543427654578949  time only: 510dfd73  time only dec: 1359871347   converted: 2013-02-03 07:02:27

65
hex: 08fc89510dfdef05   dec: 647543427654610693  time only: 510dfdef  time only dec: 1359871471   converted: 2013-02-03 07:04:31

66
hex: 08fc89510dfd7306   dec: 647543427654578950  time only: 510dfd73  time only dec: 1359871347   converted: 2013-02-03 07:02:27

67
hex: 08fc89510dfdef06   dec: 647543427654610694  time only: 510dfdef  time only dec: 1359871471   converted: 2013-02-03 07:04:31

68
hex: 08fc89510dfd7207   dec: 647543427654578695  time only: 510dfd72  time only dec: 1359871346   converted: 2013-02-03 07:02:26

69
hex: 08fc89510dfdef07   dec: 647543427654610695  time only: 510dfdef  time only dec: 1359871471   converted: 2013-02-03 07:04:31

70
hex: 08fc89510dfd7108   dec: 647543427654578440  time only: 510dfd71  time only dec: 1359871345   converted: 2013-02-03 07:02:25

71
hex: 08fc89510dfdee08   dec: 647543427654610440  time only: 510dfdee  time only dec: 1359871470   converted: 2013-02-03 07:04:30

72
hex: 08fc89510dfd7109   dec: 647543427654578441  time only: 510dfd71  time only dec: 1359871345   converted: 2013-02-03 07:02:25

73
hex: 08fc89510dfdee09   dec: 647543427654610441  time only: 510dfdee  time only dec: 1359871470   converted: 2013-02-03 07:04:30

74
hex: 08fc89510dfd710a   dec: 647543427654578442  time only: 510dfd71  time only dec: 1359871345   converted: 2013-02-03 07:02:25

75
hex: 08fc89510dfded0a   dec: 647543427654610186  time only: 510dfded  time only dec: 1359871469   converted: 2013-02-03 07:04:29

76
hex: 08fc89510dfd710b   dec: 647543427654578443  time only: 510dfd71  time only dec: 1359871345   converted: 2013-02-03 07:02:25

77
hex: 08fc89510dfdee0b   dec: 647543427654610443  time only: 510dfdee  time only dec: 1359871470   converted: 2013-02-03 07:04:30

78
hex: 08fc89510dfd710c   dec: 647543427654578444  time only: 510dfd71  time only dec: 1359871345   converted: 2013-02-03 07:02:25

79
hex: 08fc89510dfded0c   dec: 647543427654610188  time only: 510dfded  time only dec: 1359871469   converted: 2013-02-03 07:04:29

80
hex: 08fc89510dfd6f0d   dec: 647543427654577933  time only: 510dfd6f  time only dec: 1359871343   converted: 2013-02-03 07:02:23

81
hex: 08fc89510dfdec0d   dec: 647543427654609933  time only: 510dfdec  time only dec: 1359871468   converted: 2013-02-03 07:04:28

82
hex: 08fc89510dfd6f0e   dec: 647543427654577934  time only: 510dfd6f  time only dec: 1359871343   converted: 2013-02-03 07:02:23

83
hex: 08fc89510dfded0e   dec: 647543427654610190  time only: 510dfded  time only dec: 1359871469   converted: 2013-02-03 07:04:29

84
hex: 08fc89510dfd6f0f   dec: 647543427654577935  time only: 510dfd6f  time only dec: 1359871343   converted: 2013-02-03 07:02:23

85
hex: 08fc89510dfdec0f   dec: 647543427654609935  time only: 510dfdec  time only dec: 1359871468   converted: 2013-02-03 07:04:28

86
hex: 08fc89510dfd7110   dec: 647543427654578448  time only: 510dfd71  time only dec: 1359871345   converted: 2013-02-03 07:02:25

87
hex: 08fc89510dfdef10   dec: 647543427654610704  time only: 510dfdef  time only dec: 1359871471   converted: 2013-02-03 07:04:31

88
hex: 08fc89510dfd6e11   dec: 647543427654577681  time only: 510dfd6e  time only dec: 1359871342   converted: 2013-02-03 07:02:22

89
hex: 08fc89510dfdeb11   dec: 647543427654609681  time only: 510dfdeb  time only dec: 1359871467   converted: 2013-02-03 07:04:27

90
hex: 08fc89510dfd6e12   dec: 647543427654577682  time only: 510dfd6e  time only dec: 1359871342   converted: 2013-02-03 07:02:22

91
hex: 08fc89510dfdea12   dec: 647543427654609426  time only: 510dfdea  time only dec: 1359871466   converted: 2013-02-03 07:04:26

92
hex: 08fc89510dfd6d13   dec: 647543427654577427  time only: 510dfd6d  time only dec: 1359871341   converted: 2013-02-03 07:02:21

93
hex: 08fc89510dfdea13   dec: 647543427654609427  time only: 510dfdea  time only dec: 1359871466   converted: 2013-02-03 07:04:26

94
hex: 08fc89510dfd6c14   dec: 647543427654577172  time only: 510dfd6c  time only dec: 1359871340   converted: 2013-02-03 07:02:20

95
hex: 08fc89510dfde914   dec: 647543427654609172  time only: 510dfde9  time only dec: 1359871465   converted: 2013-02-03 07:04:25

96
hex: 08fc89510dfd6c15   dec: 647543427654577173  time only: 510dfd6c  time only dec: 1359871340   converted: 2013-02-03 07:02:20


Irgendwas stimmt da wohl noch nicht xD

Aber so wie es scheint, kann man erkennen, dass es zwei Datensätze sind 
und die neuesten Daten (Uhrzeitmäßig) oben sind, was irgendwie komisch 
ist...
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