VEGA VEGAPULS 61 (≥ 2.0.0 - ≥ 4.0.0) Profibus PA Approval according to LPR radio standard User Manual
Page 77
Byte-No.
1
2
3
4
5
Format
IEEE-754-Floating point value
Status
Value
AI FB
1 (OUT)
AI FB
1
Note:
Bytes 6-15 are not used in this example.
Data format of the output signal
Byte4
Byte3
Byte2 Byte1 Byte0
Status
Value (IEEE-754)
Fig. 53: Data format of the output signal
The status byte corresponds to profile 3.02 "Profibus PA Profile for Process Control Devices" coded.
The status "Measured value OK" is coded as 80 (hex) (Bit7 = 1, Bit6 … 0 = 0).
The measured value is transferred as a 32 bit floating point number in the IEEE-754 format.
Byte n
Byte n+1
Bit
7
VZ
Exponent
Bit
6
2
Bit
5
2
Bit
4
2
Bit
3
2
Bit
2
2
Bit
1
2
Bit
0
2
Bit
7
2
Bit
6
2
Bit
5
2
Bit
4
2
Bit
3
2
Bit
2
2
Bit
1
2
Bit
0
2
Sign
Bit
Significant
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
Byte n+2
Byte n+3
Bit
7
2
Significant
Bit
6
2
Bit
5
2
Bit
4
2
Bit
3
2
Bit
2
2
Bit
1
2
Bit
0
2
Bit
7
2
Bit
6
2
Bit
5
2
Bit
4
2
Bit
3
2
Bit
2
2
Bit
1
2
Bit
0
2
Significant
-9
-10 -11 -12 -13 -14 -15 -16 -17
-18 -19
-20 -21 -22 -23
-8
Value = (-1)
VZ
2
(Exponent - 127)
(1 + Significant)
Fig. 54: Data format of the measured value
Coding of the status byte associated with the PA output value
You can find further information for the coding of the status byte in the Device Description 3.02 on
www.profibus.com.
VEGAPULS
61 • Approval according to LPR radio standard
77
11 Supplement
41715
-
EN
-120301