Weather Station P03/3-RS485 • Version: 11.10.2011 • Subject to technical alterations. Errors excepted.
5
Transfer protocol
All characters and/or digits are based on the ASCII standard, i.e. every reading
processed internally as an integer or float value will always be broken down into and
transferred in its individual ASCII format characters. They must then be reassembled in
the reverse process by the receiver.
Transfer rate:
19200 Baud
Data bits:
8
Stop bit:
1
Parity:
none
The checksum is calculated along by the receiver by adding all received bytes up until
byte 35 and then compared with the checksum transferred from the P03.
Units:
Temperatures in degrees Celsius
Sun intensity in kilolux
Daylight
in
Lux
Wind in metres per second
The DCF signal can be easily interfered with. It is possible for no radio clock reception to
exist for extended periods. Therefore, only use the output time for synchronization of
another clock working in parallel in the system. For this, the second 0 should be used.
Byte
No.
Char
Meaning
1
W
Weather data start
2
OT: Sign
Outdoor temperature sign • / +
3
OT: 1st digit
Outdoor temperature 1st digit (tens)
in °C
4
OT: 2nd digit
Outdoor temperature 2nd digit (ones)
5
OT: Point
Outdoor temperature point
6
OT: 3rd digit
Outdoor temperature 3rd digit (tenth)
7
SuS: 1st digit
Sun South 1st digit (tens)
1-99 klx
8
SuS: 2nd digit
Sun South 2nd digit (ones)
9
SuW: 1st digit
Sun West 1st digit (tens)
10
SuW: 2nd digit
Sun West 2nd digit (ones)
11
SuE: 1st digit
Sun East 1st digit (tens)
12
SuE: 2nd digit
Sun East 2nd digit (ones)
13
Twilight
Twilight: J = Yes; N = No
< 10 lx
14
Daylight 0-999Lx
Daylight (1st digit hundreds)
0-999 lx
15
Daylight 0-999Lx
Daylight (2nd digit tens)
16
Daylight 0-999Lx
Daylight (3rd digit ones)
17
Wind: 1st digit
Wind 1st digit (tens)
in m/s
18
Wind: 2nd digit
Wind 2nd digit (ones)
19
Wind: Point
Wind Point
20
Wind: 3rd digit
Wind 3rd digit (tenth)
