Vega VEGABAR 53 Operating Instructions Manual page 51

Byte-No.
1 2
Format
IEEE-754-
Flieskommazahl
Value
PA-OUT
(FB1)
Fig. 18: Telegram configuration example 2
Example 3 with pressure value and additional cyclical value without temperature value:
AI (PA-OUT)
l
Free Place
l
Additional Cyclic Value
l
Byte-No.
1 2
Format IEEE-754-
Floating point value
PA-OUT
Value
(FB1)
Fig. 19: Telegram configuration example 3
Data format of the output signal
Byte2 Byte1 Byte0
Byte4 Byte3
Status Value (IEEE-754)
Fig. 20: Data format of the output signal
The status byte corresponds to profile 3.0 "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
Bit
Bit Bit Bit Bit Bit
7 4
6 5 3 2
7 4
6 2 5
VZ 2 2 2 2
Sign
Exponent
Bit
(Exponent - 127)
VZ
Value = (-1) 2
Fig. 21: Data format of the measured value
VEGABAR 53 - Profibus PA
3 4 5
Status
Status
(FB1)
3 4 5
Status
Status
(FB1)
Byte n+1
Bit
Bit Bit Bit Bit Bit Bit
0 4
1 7 6 5 3
-3
3 2 2 1 0 -1 -2 -4
2 2 2 2 2 2
Significant
(1 + Significant)
6 7 8 9
IEEE-754-
Flieskommazahl
Temperature
(FB2)
6 7 8 9
IEEE-754- Status
Floating point value
Additional Cyclic Status
Value
Byte n+2
Bit Bit Bit Bit Bit
Bit Bit Bit
4
7 6 5
0
2 1
-9 -10 -11 -12 -13 -14 -15 -16 -17
2 -8 2 2 2
-5 -6 -7
2 2 2
Significant
10
Status
Status
(FB2)
10
Byte n+3
Bit Bit Bit Bit
Bit Bit Bit
0
3 2 1 7 6 5 4
-18 -19 -20 -21 -22 -23
2 2 2 2 2 2
2 2
Significant
Supplement
Bit Bit Bit Bit
3 2 1
0
2 2 2 2
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