Endress+Hauser Profi Bus Levelflex M FMP40 - Page 55

Levelflex M FMP40 with PROFIBUS PA Operation
Endress + Hauser 55
IEEE-745 Floating Point Number
The measured value is transmitted as a IEEE 754 floating point number, whereby
Measured value = (-1)
VZ
x 2
(E-127)
x (1+F)
Example:
Byte 1 Byte 2
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
VZ 2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
2
-1
2
-2
2
-3
2
-4
2
-5
2
-6
2
-7
Exponent (E) Mantisse (F)
Byte 3 Byte 4
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
2
-8
2
-9
2
-10
2
-11
2
-12
2
-13
2
-14
2
-15
2
-16
2
-17
2
-18
2
-19
2
-20
2
-21
2
-22
2
-23
Mantisse (F)
40 F0 00 00 (hex) = 0100 0000 1111 0000 0000 0000 0000 0000 (bin)
= (-1)
0
x 2
(129-127)
x (1 + 2
-1
+ 2
-2
+ 2
-3
)
= 1 x 2
2
x (1 + 0.5 + 0.25 + 0.125)
= 1 x 4 x 1.875
= 7.5