05/02 AWB2725-1452GB
17
Range 2: –20 to +40 °C (Pt100)
The temperature is converted into a signed 15 bit value. The
weighting of the bits can be seen in the following diagram.
Example 1
If you enter these bit values in the table above, the result is the
following value:
–80 + 40 + 20 = –20 °C
Example 2
2.5 + 1.25 = 3.75 °C
If the measured value for the temperature lies outside the range
(< –25 °C or > 45 °C), then the data value is displayed as 7FFF
hex
.
The relationship between temperature and the measured value is
shown by the following equation and the diagram.
Conversion tables
Table 5: Conversion table for Pt100 (–20 to +40 °C)
b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
°C
-80 20 5 1.25 0.312 0.078 0.019 0.005
40 10 2.5 0.625 0.156 0.0390 0.01 0.002
E000
hex
=1110 0000 0000 0000
E
hex
0
hex
0
hex
0
hex
0600
hex
=0000 0110 0000 0000
0
hex
6
hex
0
hex
0
hex
Temperature
(°C)
=
Decimal value, e.g. 256 (0100
hex
)
= 0.626 (°C)
409.6
Figure 21 : Temperature/measurement diagram
4000
hex
3000
hex
2000
hex
1000
hex
0800
hex
–20
0
5
10
20
30
40
E000
hex
[˚C]
Value
Temperature
(ºC)
1)
Decimal
value
Hexadecimal
value
Pt100
resistance
(O)
-25 55296 D800 90.19
-20 57344 E000 92.16
-15 59392 E800 94.12
-10 61440 F000 96.09
-5 63488 F800 98.04
0 0 0000 100.00
5 2048 0800 101.95
10 4096 1000 103.90
15 6144 1800 105.85
20 8192 2000 107.79
25 10240 2800 109.73
30 12288 3000 111.67
35
14336 3800 113.61
40 16384 4000 115.54
45
18432 4800 117.47
1) The technical data refer to the range from
–20 to 40 ºC.
